# 13 inch Series... a few questions....



## DIYguy (Sep 18, 2008)

Here's a few more shots... 

Double brushes, hardly worn. Double pig tails/brush. Nice film on the com and no visible wear. Pretty clean on inside. Has kevlar banding. 10 tooth spline.


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## jackbauer (Jan 12, 2008)

Looks like you may have a compound wound motor. Like me. BWI is "brush wear indicator". F1 and F2 are the shunt field terminals. Put a multimeter on there and measure the dc resistance. Mine is 18 ohms.


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## Yabert (Feb 7, 2010)

Great found!!!

How and where do you find all this motors?


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## DIYguy (Sep 18, 2008)

jackbauer said:


> Looks like you may have a compound wound motor. Like me. BWI is "brush wear indicator". F1 and F2 are the shunt field terminals. Put a multimeter on there and measure the dc resistance. Mine is 18 ohms.


Thank you Jack. It never even occurred to me that it was a compound wound motor...lol. I did remember what the BWI represented...after I asked...

Now what? I have to learn about these motors. Can it be run purely as a Series motor on a regular controller?? If so, what am I giving up? If not, do I have to control the field like a sepex?


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## DIYguy (Sep 18, 2008)

Yabert said:


> Great found!!!
> 
> How and where do you find all this motors?


Is it? I'm not sure yet..lol I didn't pay much for it.... but still... I thought it was a series motor....


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## DIYguy (Sep 18, 2008)

Objective is to run this motor on a series DC motor control. Soliton1.

OK so, I'm trying to wrap my brain around the compound wound DC motor. I don't see any reason it couldn't be just used as a series motor without exciting the shunt field. It has a series winding anyways. Should work as a series motor. Yes? In this configuration, would it have less torque than a pure series motor due to the space taken on the field coils by the shunt windings? (I have no specs to compare it to other 13 inch series motors)

Second thought... (don't laugh) ... Is there any reason that the shunt winding cannot be connected in parallel with the series field winding? 
If I connected F1 to S1 and F2 to S2...linked A2 to S1/F1 and put line on A1 and F2/S2 would this give me a motor that performed most like a regular series motor... or would I burn out the shunt winding?.... No, I don't know if it is short or long shunt connected...... yet...

Thanks for any comments....

I could post a sketch if it would help....??


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## Anaerin (Feb 4, 2009)

DIYguy said:


> OK so, I'm trying to wrap my brain around the compound wound DC motor. I don't see any reason it couldn't be just used as a series motor without exciting the shunt field. It has a series winding anyways. Should work as a series motor. Yes? In this configuration, would it have less torque than a pure series motor due to the space taken on the field coils by the shunt windings? (I have no specs to compare it to other 13 inch series motors)
> 
> Second thought... (don't laugh) ... Is there any reason that the shunt winding cannot be connected in parallel with the series field winding?
> If I connected F1 to S1 and F2 to S2...linked A2 to S1/F1 and put line on A1 and F2/S2 would this give me a motor that performed most like a regular series motor... or would I burn out the shunt winding?.... No, I don't know if it is short or long shunt connected...... yet...


Looking at the diagram at http://www.micromotcontrols.com/htmls/Motor characteristics.html and if you have access directly to the series winding, then (I think) you could connect the two in parallel (provided they are the same resistance) or in series. You can also put a contactor on the extra winding and short it F1-F2 if it's in series (essentially bypassing it, as the power will prefer the low-resistance short to the higher-resistance field), or just open the connection from S1-F1 if wired in parallel for a form of field weakening (I believe). In fact, you could even isolate and reverse the shunt power to create an opposing force and weaken the field even further.

Of course, this is all dependent on the windings being equivalent and able to take the power, as opposed to (for example) a SepEx motor, where the winding more than likely won't take the power.


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## jackbauer (Jan 12, 2008)

First thing is to measure the resistance of the shunt. Secondly , do you know what voltage the forklift ran at?

If you run with no shunt the amps will be very high especially if your planning direct drive. Ideally , you want a high shunt current at startup and tail off as the vehicle speed increases. Unfortunatly this is exactly opposite to what a normal controller does.

I have found the best compromise to be running about 1/3rd shunt current via a resistor and solid state relay / fwd diode setup via the pack. If you need some more info no prob. I did a few videos on the subject last year.


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## DIYguy (Sep 18, 2008)

jackbauer said:


> First thing is to measure the resistance of the shunt.


I will measure it today... likely will bring the motor home today also.


jackbauer said:


> Secondly , do you know what voltage the forklift ran at?


 Yes, 48 volts.


jackbauer said:


> If you run with no shunt the amps will be very high especially if your planning direct drive. Ideally , you want a high shunt current at startup and tail off as the vehicle speed increases. Unfortunatly this is exactly opposite to what a normal controller does.


Would it not run as a normal series motor with shunt open? The field coils are huge with wide, flat wound conductors. I may have to pull it apart. If I can't run it with higher voltage by advancing timing... I likely wouldn't use it.



jackbauer said:


> First thing is to measure the resistance of the shunt. Secondly , do you know what voltage the forklift ran at?<br /> <br /> If you run with no shunt the amps will be very high especially if your planning direct drive. Ideally , you want a high shunt current at startup and tail off as the vehicle speed increases. Unfortunatly this is exactly opposite to what a normal controller does.<br /> <br /> I have found the best compromise to be running about 1/3rd shunt current via a resistor and solid state relay / fwd diode setup via the pack. If you need some more info no prob. I did a few videos on the subject last year.


<br /> <br /> 


jackbauer said:


> I have found the best compromise to be running about 1/3rd shunt current via a resistor and solid state relay / fwd diode setup via the pack. If you need some more info no prob. I did a few videos on the subject last year.


Thanks Jack, I did look at one of your videos last night...but it was too late to continue. So, how do u control this shunt field current then?


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## major (Apr 4, 2008)

DIYguy said:


> Is there any reason that the shunt winding cannot be connected in parallel with the series field winding?
> If I connected F1 to S1 and F2 to S2...linked A2 to S1/F1 and put line on A1 and F2/S2 would this give me a motor that performed most like a regular series motor... or would I burn out the shunt winding?


Hi Guy,

You won't burn out the shunt winding because there will be practically zero current in those coils. Do a simple calculation of current division of an 18Ω resistor in parallel with a 0.01Ω resistor. It is like exciting the shunt field with one volt when it is normally excited with 48 volts. You get 1/48th rated current. Pretty much useless, so why bother.










Something bothers me about this photo. Please post up a few more images of this area when you can.

major


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## DIYguy (Sep 18, 2008)

major said:


> Hi Guy,
> 
> You won't burn out the shunt winding because there will be practically zero current in those coils. Do a simple calculation of current division of an 18Ω resistor in parallel with a 0.01Ω resistor. It is like exciting the shunt field with one volt when it is normally excited with 48 volts. You get 1/48th rated current. Pretty much useless, so why bother.
> 
> ...


Yes, that makes sense. OK, I'll see what I can do. I basically stuck my Blackberry inside the comm end vent hole.... and snapped that. U think the winding is overheated... on the right side there? Actually, I remembered that I took a few pics in there...lemme go see what I have...

How would this motor perform used as a normal series motor u think?
Thank you..


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## DIYguy (Sep 18, 2008)

Hi Major, 

This is the only other pic I have right now... I'll try and get a few more today.

Thank you.


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## DIYguy (Sep 18, 2008)

OK, here is another pic. Turns out, it's just the insulation, potting or whatever. I scratched it with the tip of my knife blade. It's fairly soft. Looks like this is where the stuff ran when the armature was sitting after dipping or whatever they do....?

Also, I measured the shunt field. ... 8.9 ohms. My meter seems to sit at 0.2 ohms when I touch the leads together so... may be out by that much.... Series field reads 0.2 ohms, armature measures 0.4.... I guess due to brushes. 

I hooked 12 volts to it, series field only. Spun up fine.... but know I know why the motor was pulled. Drive end bearing has a groan once the shaft gets going. Sounds like bearing has dried up. Spins by hand ok with no play...
I'm glad actually, because I was wondering why this motor would have been pulled with hardly any apparent wear and tear.


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## DIYguy (Sep 18, 2008)

So, I guess the question now is... can I run this thing with my controller as a series motor and what voltage could it handle with advanced brush timing?

Would it put out some serious torque to drive my little pick-up direct drive? ..... with some balls? 

Oh yes... any idea who made this thing???

Thanks again for the help.


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## jackbauer (Jan 12, 2008)

ok we'll call it 8 ohms. so at 48v thats 6 amps. Mine is 18 ohms and ran at 72v for 4 amps max shunt. As you have a 13" and mine is an 11" i guess that sorta makes some sense.

Yes it will run as a plain series but not as well as it could. A lot depends on how the poles are wound with respect to the different fields. As an experiment connect up to run at 12v with just series field in the direction you require. Now take two wires from the shunt and touch them to the 12v battery. Note if the motor speeds up or slows down. Reverse on the shunt terminals polarity and repeat.

The best way to drive this type of motor is to have a small controller on the shunt field that supplies max or slightly more than max current at startup and low speeds and has the facility to reduce shunt when higher rpm are required. I've threatened to do this for ages but never found the time. Instead i was running at about 3.5amps shunt via a resistor and contactor from the pack. I was never really happy. Torque would fall off dramatically at about 2400rpm. One day the shunt contactor welded closed and i had to remove the fuse to get home. The car went like a rocket still pulling at 3000rpm and sounding like a gas turbine with a blown governor! Only the ammeter gave me pause for thought displaying "ovld". That only occurs over 550amps!. Eventually i played with various resistors and now run at 1 amp shunt field via a solid state relay and a free wheel diode. In this setup the shunt greatly helps the car accelerate , keeps the amps reasonable and i can still wind up to 4k rpm if i'm feeling brave. I usually change up at 3k.

This page has picks of motor teardown and brush advance:
http://www.evbmw.com/motor.html

I'm now running at 120v and am upgrading to 144v with headway cells. I'll leave the shunt setup as is as the slight increase in voltage on the series will balance out the increased shunt current. Thats the theory at least

Hope this helps.

My motor was made by "MCF" which is mitsubishi caterpillar forklift. I don't like direct drive. It limits options. That said i can start off in 4th in my car no problem but the amps are high. And thats with a 350kg agm pack.


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## DIYguy (Sep 18, 2008)

jackbauer said:


> One day the shunt contactor welded closed and i had to remove the fuse to get home. The car went like a rocket still pulling at 3000rpm and sounding like a gas turbine with a blown governor! Only the ammeter gave me pause for thought displaying "ovld". That only occurs over 550amps!. Eventually i played with various resistors and now run at 1 amp shunt field via a solid state relay and a free wheel diode. In this setup the shunt greatly helps the car accelerate , keeps the amps reasonable and i can still wind up to 4k rpm if i'm feeling brave. I usually change up at 3k.


So, how are you using the contactor? Close it for low rpm/acceleration? 

Also, when the contactor welded closed, how did removing the fuse help? The control circuit was no longer working... yes? Im confused.... 
You're saying the car pulled well at high RPM with the shunt field open then?

thanks again Jack, most helpful!


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## DIYguy (Sep 18, 2008)

jackbauer said:


> My motor was made by "MCF" which is mitsubishi caterpillar forklift. I don't like direct drive. It limits options. That said i can start off in 4th in my car no problem but the amps are high. And thats with a 350kg agm pack.


I have a 9" series in my truck now and I run it through the stock 5 speed standard trans. It works fine. I also have AGM's but 750kg of them.. I've pulled 1000 amps for short periods. 

I too am upgrading to Lithium, 65 Calb 180Ah prismatics. 

When I found this motor... I got all giddy ... thinking of the reduced weight.... gobs of torque and visions of Burube's S10 running through my little brain. I know, I know ... it has lots of tricks done to it.


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## jackbauer (Jan 12, 2008)

Its all about picking the best compromise shunt current or devising a little pwm controller. High shunt current will result in LOTS of low end torque but the high field will mean that the armature will "run out of voltage" and hence rpm very early. This is what was happening to me at 3.5amps. With no shunt you loose field strength , and hence torque. The series then has to pull lots of amps to get the vehicle moving. At 1 amp i get the best compromise between the two. 

My shunt comes on at over 5% throttle and goes off at less than 10%. I had to implement this control as i was getting insane com arcing on slow down with constant shunt. I spent some time trying to find a reason for this but could not. Once i implemented the control via throttle it went away.


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## DIYguy (Sep 18, 2008)

jackbauer said:


> Its all about picking the best compromise shunt current or devising a little pwm controller. High shunt current will result in LOTS of low end torque but the high field will mean that the armature will "run out of voltage" and hence rpm very early. This is what was happening to me at 3.5amps. With no shunt you loose field strength , and hence torque. The series then has to pull lots of amps to get the vehicle moving. At 1 amp i get the best compromise between the two.
> 
> My shunt comes on at over 5% throttle and goes off at less than 10%. I had to implement this control as i was getting insane com arcing on slow down with constant shunt. I spent some time trying to find a reason for this but could not. Once i implemented the control via throttle it went away.


hmmm very helpful Jack. Did you put any thought into how devise a parallel controller? Would PWM be overkill? Would this level of power be ok analog?

would be nice to have specs on this motor. I wonder if power could equal a pure series machine..... or better? Likely not, or racers would be using them... unless it's a controller issue??

Do you think that a proper controller scheme would have helped the arcing problem? ... and finally (ya right) I wonder about how the relationship of brush timing fits into all of this...


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## DIYguy (Sep 18, 2008)

How many degrees did you advance your brush timing Jack?. 

I advanced my 9" motor 13 degrees based on Jim Husted's advice.

From what I've been reading, this motor should be able to equal a series motor for performance on bottom end...maybe even a bit better on top end.... however, I don't know about the impact of brush advance. 

On another note. . . I'm going to talk to a local motor guy. I know a fellow who had been running a motor shop rebuilding/rewinding all types of motors for over 30 years. He has no experience in EV application (I don't think) ... but I'm gonna pick his brain a bit on Monday. Maybe he has some "spare parts" lying around....


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## jackbauer (Jan 12, 2008)

Certainly no controller exists (outside a forklift) for a compound motor. I have heard that some forklift controllers run differential compound (this is where the fields oppose instead of add) to maintain speed on an incline. Not very desirable in an ev where you want cumulative compound so the fields help each other. My controller is a homemade igbt variant of the open revolt. Paul and the team wrote some custom code so as i could use a spare pin on the microcontroller as an on/off signal to the shunt field. I had and still do plan to build a little shunt controller addon but just havent had the time. The fact that it runs well with the current setup doesnt help the motivation.

High shunt current would be ideal for around town or towing to maximise torque and minimise armature current where speed is not essential. Lean off the shunt and armature current and rpm must increase to maintain a given back emf.

I'm no motor expert but i think the compound is as good as if not better in some ways than the pure series. One major advantage is that if the throttle is floored in neutral it won't rev to destruction as long as shunt current is high enough. I had a graphic demonstration of this when my car went for its roadworthiness test and they guy floored it in first in the car park.


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## jackbauer (Jan 12, 2008)

I went about 12 degrees advance. Be a little careful of "motor guys" outside the ev scene. I spoke to quite a few and got responses ranging from blank stares to "that can't be done".

Only recently i needed some brushes for one of the motors i'm using in the bike. When i couldn't provide the make and model of the forklift the motors came from , none of the motor shops could help. Twenty minutes and fifty dollars later i had them ordered from the states on the internet. No wonder Ireland is bankrupt


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## DIYguy (Sep 18, 2008)

jackbauer said:


> I went about 12 degrees advance. Be a little careful of "motor guys" outside the ev scene. I spoke to quite a few and got responses ranging from blank stares to "that can't be done".
> 
> Only recently i needed some brushes for one of the motors i'm using in the bike. When i couldn't provide the make and model of the forklift the motors came from , none of the motor shops could help. Twenty minutes and fifty dollars later i had them ordered from the states on the internet. No wonder Ireland is bankrupt


No doubt. I had a similar experience when I was doing my 9". 

I want to show what I picked up for $100 Cdn. 

The hand crank lift... this thing is sweet! good for working on and installing (some types of install)

Two circumferential clamps.. could use for part of mount system.

A variety of spline adaptors and U-joint clusters. Large and small format. Good for making a new direct drive driveshaft..  They all fit my motor. 

Oh yes,... the motor also...

I actually offered $300 for the lot. I've been doing some work for this guy and he was really nice to me for it....


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## DIYguy (Sep 18, 2008)

Any thoughts on that other picture Major? Is that what you were wondering about? I could take some others if needed?


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## major (Apr 4, 2008)

DIYguy said:


> Any thoughts on that other picture Major? Is that what you were wondering about? I could take some others if needed?


Looks like some weird stuff in there. Maybe just balance putty 

Then it is also weird that you can see so much of the top of the armature teeth when it appears to be aligned under a pole. Is the armature core longer than the pole? Is it displaced? Is the air gap huge? Is it just an optical illusion?

major


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## DIYguy (Sep 18, 2008)

major said:


> Looks like some weird stuff in there. Maybe just balance putty
> 
> Then it is also weird that you can see so much of the top of the armature teeth when it appears to be aligned under a pole. Is the armature core longer than the pole? Is it displaced? Is the air gap huge? Is it just an optical illusion?
> 
> major


Yes, I see what you mean. The armature core does extend about 1/2" past the end of the pole. The windings extend further of course. I'm going to see if I have time to pull it apart later this evening. Gotta keep the wife happy first.... B-day... u know... and laying a hardwood floor also. 

Cheers, and thanks for the help!


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## DIYguy (Sep 18, 2008)

No time last night, but I took a crack at it this morning. U know, I was thinking...another advantage of an electric motor for motive power. .. you can completely disassemble one in 1 to 1.5 hours, if you have what you need.

Now I understand this motor a lot better. I actually thought that the shunt winding was "WITH" the series winding...albeit insulated from same ...but on the same iron poles. This motor actually has two larger series windings and two opposed shunt windings that are much smaller. (sorry about the one pic...must have been moving a bit when I snapped).

I also pulled the bearings. One was leaking as the seal was not seated properly. I think that it was likely damaged when originally built as this motor has practically no wear. 

Man, this friggin thing is heavy.

I was also wondering how the BWI worked. Now I understand that also. 

Oh yes, the armature core is 1" longer than the pole shoes.... so, .5" each end extends.


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## jackbauer (Jan 12, 2008)

Thats the same winding layout as mine. Two poles series and two shunt. The brush gear looks the exact same also.


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## DIYguy (Sep 18, 2008)

I think... . I'm going to get this motor rewound to series with interpoles. I know this may not be a popular choice... I mentioned it once before for another motor and it didn't get a lot of support. However, from the little I do know so far... this is the best way to go. After that the Warp11HV came out with interpoles. The racing motors have them... at least some of them do.

I think my commutator bar count is not that high..(higher count seems to be a good thing for running higher voltage)...but maybe is capable of large current handling...?? (that's a question... lol) Perhaps if it was higher, I would just do a series rewind and advance the timing. So, by adding interpoles to counteract the brush arcing, I should be able to run a pretty high voltage and handle 1000 amps (probably a lot more, for short time) if I want.

Now to find a good place to get this done locally. I know Jim would be the best one, however, I don't want to ship this thing that far. Perhaps a good motor shop could wind it to the specs of another 13" series motor they have info on?


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## DIYguy (Sep 18, 2008)

jackbauer said:


> That's the same winding layout as mine. Two poles series and two shunt. The brush gear looks the exact same also.


Hey Jack. Really? Well, it did come out of a Caterpiller forklift...so, it very well could be made by the same manufacturer. Did yours have dual brushes? (8) or single (4)?
Cheers.


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## DIYguy (Sep 18, 2008)

major said:


> Then it is also weird that you can see so much of the top of the armature teeth when it appears to be aligned under a pole. Is the armature core longer than the pole? Is it displaced? Is the air gap huge? Is it just an optical illusion?
> 
> major


I was thinking about this also...and while the series coils extend a lot passed the armature core, the shunt windings are considerably shorter allowing more room to take a picture and showing more of the armature.


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## jackbauer (Jan 12, 2008)

Sounds a bit ambitious. Then again i'm very much an "off the shelf" type of guy. At a guess you'd spend as much if not more on a rewind than buying say a kostov with interpoles. Just my 2c by all means go for it!

edit: yeh mine is a 8 brush. See pics here:
http://www.evbmw.com/motor.html


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## DIYguy (Sep 18, 2008)

jackbauer said:


> Sounds a bit ambitious. Then again i'm very much an "off the shelf" type of guy. At a guess you'd spend as much if not more on a rewind than buying say a kostov with interpoles. Just my 2c by all means go for it!
> 
> edit: yeh mine is a 8 brush. See pics here:
> http://www.evbmw.com/motor.html


 ur an off-the-shelf-guy? hehehe. Man u build stuff I wouldn't even attempt to make. u've done stuff no one else on here has done!
This motor rewind seems easy to me... but then again, I wouldn't want anyone to confuse me with the facts...lol If I can get the materials, I will do it myself. If not, I will see what it costs. I basically I got the motor for free so, lets see what the total really is. You may be right... but I'm gonna find out.

I see your brushes are doubled up. Looks very similar.

Kostov doesn't sell 13" motors do they? Some think they aren't as rugged either.... not sure. 
The Warp 11HV costs $3,500 US.
The Warp 13 is over $5,000 US and it doesn't come with an HV or interpole option. 
So, I don't think I could buy anything off the shelf that would compare. 

Would it cost me $5,000 to rewind it and add interpoles? $3,000 ? 
I dunno, I'm thinking it would be a lot less.. but, I really don't know yet.


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## DIYguy (Sep 18, 2008)

Wholly crap, I just had an idea....
There were two motors, ....but I only took one. The other had some issues. Besides being well used, the DE casting was broken. This in itself isn't a big issue, but the splines on the shaft were severely damaged. I guess it could be turned down also..... but, it just occurred to me... it has two more series coils? ! lol hehe


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## jackbauer (Jan 12, 2008)

Yeh kostov do a 13". You just might be able to transplant the series windings from the donor motor into the good one. If you do then consider making the donor into a shunt dc generator. I honestly don't know how much a rewind would cost.

I guess what i meant to say was that i've found designing everything from scratch rarely results in a finished project. Better to use some ready made building blocks sometimes ...........


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## DIYguy (Sep 18, 2008)

jackbauer said:


> Yeh kostov do a 13". You just might be able to transplant the series windings from the donor motor into the good one. If you do then consider making the donor into a shunt dc generator. I honestly don't know how much a rewind would cost.
> 
> I guess what i meant to say was that i've found designing everything from scratch rarely results in a finished project. Better to use some ready made building blocks sometimes ...........


ok, wasn't sure about that. I think the donor is also a compound wound motor. This means there are two series windings in each and two compound windings. So, I was thinking to use all four series windings in one motor...and maybe I could even cut down the other 4 poles to use as interpole shoes???? In other words...or in your words... "some ready made building blocks"...  

Wire size, flux density, number of turns etc. . etc. I dunno. YET! lol


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## major (Apr 4, 2008)

DIYguy said:


> Oh yes, the armature core is 1" longer than the pole shoes.... so, .5" each end extends.


Hi guy,

It is unusual to have the armature core longer than the pole length. Not that there is anything wrong with that 












Notice how much darker the shunt coil is? And it is noticeably smaller than the series coil. My guess is that the shunt field was running a lot hotter than the series field. The designer should have use more copper and made it about the same size as the series coil. 

That and core length make me wonder if this is that good of motor design. Proof in the pudding, I guess. And I worked with Cat Lift Trucks years ago. Back then they were really hard azz about such stuff from vendors. But then, this may not have been an OE motor. And you said you found a damaged bearing also. 

But, it looks like a robust beast. And I have seen worse things in motors 

major


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## DIYguy (Sep 18, 2008)

Hi Major,

Yes, the colour of the field coils struck me right away. Definitely been running hotter. The bearing had an issues with the seal not being seated properly. It was leaking. I dunno.

I just found some pics and some other written stuff that leads me to believe that the interpoles are wound with the same heavy gauge as the series coils. For some reason, I just thought it would have been lighter stuff...but I guess it makes sense since I also read that these are in series with the armature...so, they have to be able to carry the heavy current. I found these pics... of what I want it to look like.... 

My series coils are way to big to allow room for interpoles. Some copper is going to have to come off. They are huge compared to this kostov.


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## Georgia Tech (Dec 5, 2008)

DIYguy said:


> No time last night, but I took a crack at it this morning. U know, I was thinking...another advantage of an electric motor for motive power. .. you can completely disassemble one in 1 to 1.5 hours, if you have what you need.
> 
> Now I understand this motor a lot better. I actually thought that the shunt winding was "WITH" the series winding...albeit insulated from same ...but on the same iron poles. This motor actually has two larger series windings and two opposed shunt windings that are much smaller. (sorry about the one pic...must have been moving a bit when I snapped).
> 
> ...


 It is possible that at one time the Poles in this motors was changed out for some reason or another.... This could be the reason for the Core lengths not matching up..Yes it will change in how it runs..Less flux means more RPM per volt and less torque per amp!


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## Georgia Tech (Dec 5, 2008)

DIYguy said:


> I think... . I'm going to get this motor rewound to series with interpoles. I know this may not be a popular choice... I mentioned it once before for another motor and it didn't get a lot of support. However, from the little I do know so far... this is the best way to go. After that the Warp11HV came out with interpoles. The racing motors have them... at least some of them do.
> 
> I think my commutator bar count is not that high..(higher count seems to be a good thing for running higher voltage)...but maybe is capable of large current handling...?? (that's a question... lol) Perhaps if it was higher, I would just do a series rewind and advance the timing. So, by adding interpoles to counteract the brush arcing, I should be able to run a pretty high voltage and handle 1000 amps (probably a lot more, for short time) if I want.
> 
> Now to find a good place to get this done locally. I know Jim would be the best one, however, I don't want to ship this thing that far. Perhaps a good motor shop could wind it to the specs of another 13" series motor they have info on?


 DIYguy, If you can pull off retrofitting this motor with interpoles PLEASE tell me how you did it... I would LOVE GREATLY to help you in this endevore. I Also have a 13 inch motor with low Com Bar count. Its quit a bit longer but has tons! of room in the field housing with the poles and winding! Hey, man it will be a heck of a project but I would love to support you on this!!!


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## DIYguy (Sep 18, 2008)

Georgia Tech said:


> It is possible that at one time the Poles in this motors was changed out for some reason or another.... This could be the reason for the Core lengths not matching up..Yes it will change in how it runs..Less flux means more RPM per volt and less torque per amp!


Naaa, I don't think there are too many other fools like me. (...and you..lol)


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## DIYguy (Sep 18, 2008)

Georgia Tech said:


> DIYguy, If you can pull off retrofitting this motor with interpoles PLEASE tell me how you did it... I would LOVE GREATLY to help you in this endevore. I Also have a 13 inch motor with low Com Bar count. Its quit a bit longer but has tons! of room in the field housing with the poles and winding! Hey, man it will be a heck of a project but I would love to support you on this!!!


hehe, I do remember you talking about this.... back when I was also talking about it. I've been doing some research.. not much out there. I have also been corresponding with Plamenator... the guy from Kostov. I figured, why not ask the guys who build these things. he has no reason to want to help me...but he has been awesome! I'm learning a bit every day. It seems not to terribly hard to do.... but I don't think it is something I can do at home. Tight winding is important... we'll see.
I know a guy who has been running an industrial motor rewind shop for 35 years. I'm going to talk to him.

I appreciate the support. You have to promise me one thing.... that if you get ur 13" motor done.... u don't put it in a go-kart! lol


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## DIYguy (Sep 18, 2008)

Well, been a busy day. . but I did manage to get the other set of series coils and all four pole shoes. The motor is suppose to be the same spec..but u can see that the coils were wound a little tighter/smaller...not much, but the radii are tighter also.

The motor guy wasn't much help on this topic (U were right Jack)...other than keeping an eye out for another doner...perhaps he will find one with interpoles, but I doubt that. Well, he did have some good ideas.... 

Plamen has been a lot of help. Here are some tidbits. 

The calculation for the interpoles is quite elaborate... and he says that they always use it as a guide and then verify through testing. For my 37 bar count, he suggests 5 turns. He also says that the wire should be 20 to 25% heavier than the series wire. (and I originally thought the wire was smaller...). He says that laminated shoes would improve efficiency "slightly" but probably not an issue with a series motor.

I asked about a verification test. He recommends loading the motor, perhaps 80 volts and 200+ amps for 10 minutes and measure the com temp with and without interpoles. I dunno, I could build a simple hydraulic dyno... or maybe figure out another way to load the motor... ?? Or not do it at all...lol (how about a Jackbauer video. I thought of this also...but never tried it) I guess I'll first see if I can actually do this... before worrying too much about testing it....

I would very much appreciate any other advice on this topic. 

I have some questions about interpole polarity WRT the series coils...but I will leave this alone for now..... I have some more reading to do on it.

Any thoughts on the RPM this thing will handle would be most welcome. 

I tried sending a message to Jim Husted...but I don't know if his email is working...the site/domain seems to have expired. He has helped me in the past also.

Cheers,


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## DIYguy (Sep 18, 2008)

Here are a few pics ...just for the heck of it....

One of the field coil that I wont be using... (goes in the scrap copper bin) Note the small dia wire.

One of the stripped series coils. This has two - double wires wrapped 11 times around.

The other set of series coils also has 11 turns but the wire is two singles...but twice the thickness. I assume the current carrying and field generated would be the same....??

I'm having a hard time stripping the second set of coils. They have baked resin over the banding.... argh!

Oh yes, I threw in one pic of a field coil with the shoe out of it. Turns out, the black appearance is likely not from overheating. They used some black Nomex or insulating tape on the ends, over top of the other colour stuff.


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## Georgia Tech (Dec 5, 2008)

DIYguy said:


> Here are a few pics ...just for the heck of it....
> 
> One of the field coil that I wont be using... (goes in the scrap copper bin) Note the small dia wire.
> 
> ...


 
Takening guess here but I think you would want the same turn ratio on the Interpole as on the field pole.....

The REAL question is how much room do you have between the main filed poles?

Also if you ARE successful with this Interpole project, It would be REALLY nice if this machine was a SepEx motor!!


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## DIYguy (Sep 18, 2008)

Georgia Tech said:


> Takening guess here but I think you would want the same turn ratio on the Interpole as on the field pole.....


Actually not. The recommendation from Kostov is to put as many turns on the series coils as possible. The interpoles field strength is a complicated calculation apparently, but recommendation for my 37 bar count com, is 5 turns on the interpoles.



Georgia Tech said:


> The REAL question is how much room do you have between the main filed poles?


This is the challenge. One thing I see that is an issue, is the base width of the shoes for the series coils. If you look at the ones that came out of my motor, they are quite wide. The ones in pics from Kostov are narrow at the base and flare wider close to armature. This is how they make room for the windings. My options are to find other shoes that are suitable, or modify these ones. 



Georgia Tech said:


> Also if you ARE successful with this Interpole project, It would be REALLY nice if this machine was a SepEx motor!!


Sorry, but I don't understand this. My whole purpose is to make this a series motor that will take higher voltage without advance and run on a standard controller....since they are available. Being compound wound...it really was (or could be) a Sepex motor when I started...
Why would you want this?


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## Georgia Tech (Dec 5, 2008)

DIYguy said:


> Actually not. The recommendation from Kostov is to put as many turns on the series coils as possible. The interpoles field strength is a complicated calculation apparently, but recommendation for my 37 bar count com, is 5 turns on the interpoles.
> 
> 
> This is the challenge. One thing I see that is an issue, is the base width of the shoes for the series coils. If you look at the ones that came out of my motor, they are quite wide. The ones in pics from Kostov are narrow at the base and flare wider close to armature. This is how they make room for the windings. My options are to find other shoes that are suitable, or modify these ones.
> ...


 
I would LOVE to know the formuals and calculations for figureing interpole design. I tough having the same number of turns (NI) would be need to counter act the turns on the main poles (NI).... Hey but who am I... LOL.. I need to get you some pictures of my 13 inch series motor and you tell me what you think? 

Well as far as a Sep Ex I fugure they were easier to controll and also they would provide real easy regen! I don't know sereis is cool though. If by some strang mirical I get interpoles in my 13 inch motor, I will then put them in the sepex version of this motor as well...

Like I said I will post pictures and show you, this motor I have has tons of room between the poles...


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## DIYguy (Sep 18, 2008)

I'm probably not the guy you want too much advice from on motors...

If you look at my pole shoes, you can see the wide base as compared to the ones in this Kostov motor. I need to make some room for copper! Off to the machine shop....


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## Tesseract (Sep 27, 2008)

DIYguy said:


> ...If you look at my pole shoes, you can see the wide base as compared to the ones in this Kostov motor. I need to make some room for copper! Off to the machine shop....


I wouldn't be so quick to cut down the pole shoes... They concentrate the magnetic field produced by the windings to create the highest possible amount of useful torque per amp-turn. That is to say, the number of turns on the pole shoe, the area and type of ferromagnetic material used, and the field current are all intertwined here. Trying to increase one without the other just results in a less efficient design.

In other words, TANSTAAFL.


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## DIYguy (Sep 18, 2008)

Tesseract said:


> I wouldn't be so quick to cut down the pole shoes... They concentrate the magnetic field produced by the windings to create the highest possible amount of useful torque per amp-turn. That is to say, the number of turns on the pole shoe, the area and type of ferromagnetic material used, and the field current are all intertwined here. Trying to increase one without the other just results in a less efficient design.
> 
> In other words, TANSTAAFL.


Hey Jeff. Yes, it is true. This is the basis of an effective electromagnet. I did study it some years ago in a slightly different context... none the less, same principals. Weld power supply transformer design. Now, inverters are used for most designs and switching frequencies are very high, therefore transformer mass is much less. Wave forms can be controlled etc.... 

Ok, back to the topic of the poles....This motor, being compound wound, had the requirement of only two heavy wound large series coils. As you mentioned, to get the strongest magnetic effect, the poles were large, the windings were large etc. Since the field windings use much smaller wire, the "other half" (less than) of the internal circumference didn't need to occupy as much space. Obviously, they used the same shoes though. I know that similar series motors with interpoles use shoes with smaller bases (although full width surface areas to effect armature)... and I suspect that plain series motors of similar size lie somewhere in the middle. Regardless of the interrelationships with number of turns, pole base width and wire size....there is only so much inner circumferential area. You cannot keep the same size of pole shoe AND coil wire/turns AND add interpoles. Don't gotts enuff ruuum! 

So... even though I really don't have any modeling software for motor design (let alone the knowledge to do it with a pencil)... It not completely an act of hack and slash.. lol. Kostov is helping me out a lot with guidance (no guarantees though...lol). Now... I'm getting hungry... any free lunch around here???


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## major (Apr 4, 2008)

DIYguy said:


> If you look at my pole shoes, you can see the wide base as compared to the ones in this Kostov motor. I need to make some room for copper! Off to the machine shop....












Hi guy,

It is called the pole body. If the original design was proper, the pole body would not saturate, may run at 90% of the saturated flux level. You indicate cutting the pole body cross section down close to half. No question in my mind this will cause early saturation resulting in a loss of maximum torque from the motor possibly to the tune of 30, maybe 40%.

You will likely see that machines designed for interpoles have a larger diameter yoke than those non-interpole machines using the same armature. Or conversely, motors of the same frame diameter will use smaller armatures when they have interpoles. It is not just a case of hacking away steel to make the crap fit in there 

I am all for you playing around (I mean experimenting ) with motors. Great. But I do fail to see a legitimate objective for adding interpoles to a series wound motor intended for a non-regen, non-reversing application. But WTH, good luck.

major


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## DIYguy (Sep 18, 2008)

Hey Major. Thanks for chiming in.


major said:


> Hi guy,
> It is called the pole body. If the original design was proper, the pole body would not saturate, may run at 90% of the saturated flux level. You indicate cutting the pole body cross section down close to half. No question in my mind this will cause early saturation resulting in a loss of maximum torque from the motor possibly to the tune of 30, maybe 40%.


And thanks for the correction. Loss of torque generated by the 2 series coils? That's ok... I will have two more.... lol 
I suspect though, that your assumption would be based on keeping the same size and number of turns in the coil. I will try and use the same wire, but the number of turns will be reduced. This should help with saturation. I expect some "loss" of potential power (granted it was in a compound configuration before) 



major said:


> You will likely see that machines designed for interpoles have a larger diameter yoke than those non-interpole machines using the same armature. Or conversely, motors of the same frame diameter will use smaller armatures when they have interpoles. It is not just a case of hacking away steel to make the crap fit in there


 Apparently, interpoled motors usually have smaller wire cross section also than their series brothers... I'm told. ??



major said:


> I am all for you playing around (I mean experimenting ) with motors.


 Thank goodness, I need all the help I can get! 



major said:


> Great. But I do fail to see a legitimate objective for adding interpoles to a series wound motor intended for a non-regen, non-reversing application. But WTH, good luck.
> major


Perhaps I will save someone else the heartache.... 
Kostov describes some of it like this....
IS THERE ANY EMPIRICAL EVIDENCE ON THE EFFECT OF THE INTERPOLES? 
We have performed tests on an interpoled Kostov 9" 80V motor. One would think that 80V is relatively low and does not justify the use of interpoles. Indeed it may be so for low rpm, low amp forklift motors but the data shows this not to be true for EV conversion motors. For example most good EV motors have more than 4000rpm and 200A. The Kostov 9" 80V usually has collector temperature change of 120K in 60 minutes of work (up to 140K according to standard) at 280A. Removing the interpoles results in temperature change ot 157K in JUST 10 minutes. Advancing the brushes by 8/12 degrees improves the number to 147/141K but still in only 10 minutes. 
and this.....
HOW DO INTERPOLED CONSTRUCTIONS DIFFER FROM ?STANDARD? MOTORS? 
The change is in several aspects: 1) The lack of interpoles creates a disbalance above 60-70V; the commutator is very hot while the armature/stator windings are cold. 2) This calls for few bars in the commutator so that the bars can be big to dissipate heat. 3) Few commutator bars call for a much longer armature so that torque/rpm can be reasonable. 4) The result is a long and heavy motor whose commutator is on the brink of melting but armature/stator windings stay uselessly cold. On the other hand, interpoles reduce brush arcing so that commutator temperature falls down. This allows a bigger bar count and shorter armature stack making the motor much lighter than its non-interpoled counterpart. Therefore for a comparable power, an interpoled motor has less weight (20-40%), bigger diameter but much shorter body and the ability to handle high voltage. Less weight means a cheaper motor and of course more range.  

Of course in my case... i'm using an existing motor. I suppose the ability to run higher voltage (therefore more power) and the benefits that come with this. I would ask, why is everyone wanting a Warp11HV and why do the smartypants racing guys have interpoles?

You can call it playing around.. I don't mind. I never claimed to know much about motors. Most of what I know...has come from what you have written. Maybe what I'm doing won't work. But I'm learning stuff.  Or maybe it will...


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## major (Apr 4, 2008)

DIYguy said:


> I would ask, why is everyone wanting a Warp11HV ?


Hype 



> and why do the smartypants racing guys have interpoles?


If you're talking about drag racing, the quickest fastest guys do not use interpole motors  I think CroDriver is the only smartypants I know about using interpoles. And he isn't the fastest quickest, yet 

I'll try to address some of those other points later. But do remember, there are multiple methods to remove the epidermis from a feline animal


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## DIYguy (Sep 18, 2008)

Well don't wait too long.... I won't be able to put the hide back on this cat....


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## DIYguy (Sep 18, 2008)

For all you motor-challenged guys like me... this is excellent reading. It starts off with some stuff from your distant memory....but gets better as you go.

http://www.reliance.com/mtr/mtrthrmn.htm


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## electromet (Oct 20, 2009)

DIYguy,

Thanks for the link. I've been looking for something like this for a while now.


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## major (Apr 4, 2008)

DIYguy said:


> Well don't wait too long.... I won't be able to put the hide back on this cat....


O.K. I'll try to keep it short.



DIYguy said:


> For all you motor-challenged guys like me... this is excellent reading. It starts off with some stuff from your distant memory....but gets better as you go.
> 
> [URL]http://www.reliance.com/mtr/mtrthrmn.htm[/URL]


I like that resource. Rather basic, but well written and right-on for the most part. See figure 23. It is a representation of the saturation curve which is the magnetic characteristic for the iron circuit of the motor. The vertical axis is really flux and usually flux per pole. They use voltage to make it simple, and voltage (armature generated voltage) is proportional to flux. And the horizontal axis is really mmf, magnetic excitation, or NI, ampere-turns per pole.

Now NI, ampere-turns per pole, does not matter if it comes from a series coil or a shunt coil, or on one pole of the pole pair or split between both poles of the pole pair.

Back to that curve: You notice that the curve starts out on an almost linear increase from the origin but starts to bend over as the excitation increases. This particular curve is not real well drawn, but anyway, you see to the far right where it appears to have maxed out? That is the point of saturation. Meaning additional mmf (ampere-turns on the field) will not result in more flux.

This saturation is a result of the magnetic material (steel) which has a maximum flux density. There is no changing that. And also the geometry of the magnetic circuit, the steel path in the motor which supports the magnetic flux. The flux at any cross section of the magnetic path is the flux density times the cross sectional area. 

If, in this magnetic circuit, you decrease the cross sectional area to the point where the flux density reaches saturation, you will decrease the vertical distance where that saturation curve "knees" over. So when you mill out that pole body, you reduce the maximum flux, perhaps considerably, like 30 to 40%

Now in that article from Reliance, you can find the motor torque equation. It will look something like this:

T = Kt * Ia * Flux

T = Torque produced in the armature, Kt is machine constant (basically number of armature conductors), Ia is armature current, and Flux is the magnetic flux from that saturation curve.

It is easy to see that if you decrease the maximum flux, you have decreased the torque at your maximum current. And you can put as many turns as you want on those field poles, it will not change the fact that the maximum flux has been reduced.

Well, I guess, not too short. Anyway, I hope you followed what I was trying to say.

Regards,

major


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## Georgia Tech (Dec 5, 2008)

Major, I know I sould not be asking this but....

If I have 2 motors a Sepex and a series, and lets say they have the exact same magnetic deminions such as Lam stack Poles, diameter, slots, ect... one is just wound SepEx and the other series. 
Is it possbile that they BOTH could make the same stall torque potentially? Or will the series motor ALWAYS by nature have more stall torque?


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## DIYguy (Sep 18, 2008)

yes sir... I get it. I actually knew this... believe it or not..  (told ya I'm learning)

So, for them racing smartypants.. maximum torque comes from the most armature current you can push through without field saturation. This is likely higher in a series motor with a yoke of size X than in an interpoled motor with a yoke of size X. . edit... because there is more space....
The additional heat generated at the commutator is not a big issue since they are only running for less than 15 seconds. As long as you can keep the com from zorching..... and this is accomplished with brush advance.... allowing commutation to occur during a period of weaker field.

What about for EV applications where you want high torque... but also want to run for longer periods of time?


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## major (Apr 4, 2008)

DIYguy said:


> So, for them racing smartypants.. maximum torque comes from the most armature current you can push through without field saturation.


No, you can bet those idiots are saturated 



> What about for EV applications where you want high torque... but also want to run for longer periods of time?


Size the motor for power and use gears to get your torque


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## DIYguy (Sep 18, 2008)

major said:


> No, you can bet those idiots are saturated
> 
> 
> 
> Size the motor for power and use gears to get your torque


I meant without a transmission....


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## major (Apr 4, 2008)

Georgia Tech said:


> If I have 2 motors a Sepex and a series, and lets say they have the exact same magnetic deminions such as Lam stack Poles, diameter, slots, ect... one is just wound SepEx and the other series.
> Is it possbile that they BOTH could make the same stall torque potentially?


If you provide equal excitation (ampere-turns) and have equal armature current, then the torque will be the same. See that equation, T=Kt*Ia*Flux.


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## DIYguy (Sep 18, 2008)

major said:


> If you're talking about drag racing, the quickest fastest guys do not use interpole motors


Hey Major, was just thinking about this... if there is as much as 2% torque per degree of brush advance "lost"... and the ability to run much higher voltages....why don't these guys use interpoles? Is it purely due to the room given up to otherwise "torque-occupying" copper conduction wire around the poles?


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## DIYguy (Sep 18, 2008)

look what I found.... From Dennis Berube. Apparently, he runs this 13" motor up at 348 volts??? 

> > > After 2 months of work on the interpole 13 inch GE its ready to hit the
> > > track. Its the best motor I have built to date, by far. I realize I do not
have
> > > a lot of battery on tap but with 2006 actual motor amps out to 80 +mph
> > > there is 0 arcing. There is not even the WHITE line I like to see under
the
> > > brushes. The timing is set at . 5 degrees advance, but that may change at
> > > Firebird after a couple runs.
> > >
> > > I think it could take every bit of 4000 amps, at hi voltage.
> > >
> > > Dennis Berube


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## major (Apr 4, 2008)

DIYguy said:


> Hey Major, was just thinking about this... if there is as much as 2% torque per degree of brush advance "lost"... and the ability to run much higher voltages....why don't these guys use interpoles? Is it purely due to the room given up to otherwise "torque-occupying" copper conduction wire around the poles?


Hi DIY,

I don't know for sure. Guess it might be what's available to them and what works. About the only interpole machines have been Kostov and those who have run those have gone back to the non-interpole motors. And it is not an easy task to modify an existing motor design to add interpoles and come out with a good performing machine, especially with the type of duty cycle these guys do.

You are correct that the interpoles and comm coils do not contribute to torque production yet consume space and displace mass which otherwise could. However to get the motor to survive commutation, brush advance also reduces torque. 

I've heard about a few secret weapons in the fight against Mr. Zorch. But I can't speculate on that. 

major


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## Jimdear2 (Oct 12, 2008)

Just a couple of maybe silly questions about controlling High Voltage problems.

I was thinking about some form of motor and brush cooling for our 13 inch when we go to sand drags and wondered if gas expansion cooling with nitrogen, CO2, heilium or argon or some other gas would be a good non parasitic cooling method. Then I started to wonder if sealing off and flooding the brush area with a nobel gas might not help with arcing and zorching while the expansion was cooling things down? Maybe not require as much brush advance.

Second thought was on interpoles, I'm sure this has been thought of but can interpoles be placed on the outside of the motor barrell? If they were designed for external mounting I'm sure the proper magnetic field effect could be produced to get weakining. Wonder also if they were outside if they could be shifted to help with arcing at different rpm?

Sorry if my ignorance is showing. If they are bad or disproven ideas let me know so I don't waste time covering bad ground.

Thanks,
Jim


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## major (Apr 4, 2008)

Jimdear2 said:


> I was thinking about some form of motor and brush cooling for our 13 inch when we go to sand drags and wondered if gas expansion cooling with nitrogen, CO2, heilium or argon or some other gas would be a good non parasitic cooling method. Then I started to wonder if sealing off and flooding the brush area with a nobel gas might not help with arcing and zorching while the expansion was cooling things down? Maybe not require as much brush advance.


Hi Jim,

For large motors on very short runs, like under 20 seconds, effective cooling can be done between runs with forced air. Providing an atmosphere less conducive for Mr. Zorch has been discussed and may be worth pursuing. I can't tell you what to use or a good way to test it without risking the motor. But you would have to run the motor for quite a while to seat the brushes and film the comm. And likely do the same thing over again after hard runs. Which is a good idea anyway. The seating and filming process requires air with some water vapor.



> Second thought was on interpoles, I'm sure this has been thought of but can interpoles be placed on the outside of the motor barrell? If they were designed for external mounting I'm sure the proper magnetic field effect could be produced to get weakining. Wonder also if they were outside if they could be shifted to help with arcing at different rpm?


Unlike the your first thought, I'd say this second thought has no merit. Those interpoles have to be inside there, afterall, they are interpoles, not outerpoles 

major


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## Guest (Dec 5, 2010)

Actually more like between poles.


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## Jimdear2 (Oct 12, 2008)

major said:


> Hi Jim,
> 
> For large motors on very short runs, like under 20 seconds, effective cooling can be done between runs with forced air. Providing an atmosphere less conducive for Mr. Zorch has been discussed and may be worth pursuing. I can't tell you what to use or a good way to test it without risking the motor. But you would have to run the motor for quite a while to seat the brushes and film the comm. And likely do the same thing over again after hard runs. Which is a good idea anyway. The seating and filming process requires air with some water vapor.


Major,

Thanks for your answer. Nice to actually come up with something others think might be of value.

Since my health doesn't let me do what I want anymore, I entertain myself with thought exercises like this. I guess you take what fun you can get.

I am always looking at worst case and trying to come up with answers. (Usually answers to questions that don't need to be asked). 

I'll have to say that I'll probably never be in a position to try something like this. All of our developement on the puller is being financed by a poor retired guy (me) . Hope somebody else can run with it.





major said:


> Unlike the your first thought, I'd say this second thought has no merit. Those interpoles have to be inside there, afterall, they are interpoles, not outerpoles
> 
> major


Well one out of two isn't too bad.

Question on brush seating, I've heard about brush seating compound and wondered what your opinion was? Better to do it naturally or is the compound OK?

Have a great Holiday Season,
Jim


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## major (Apr 4, 2008)

Jimdear2 said:


> Question on brush seating, I've heard about brush seating compound and wondered what your opinion wa?. Better to do it naturally or is the compound OK?


Compound  Don't like the sounds of that. They do make what they call seating stones which are really dressing stones. They will shape the brushes to the comm diameter. Something which should have been done at the motor factory. But actual seating and filming requires running time. It is hard to put a load on the motor to get proper brush and comm break-in (seat and film). So running at 12V no load (low current) is usually done. I recently did this with a Warp9 for about 20 hours. Off and on over about a week as I was working on other car parts. Even after that, it is recommended to take it easy on the road for a few hundred miles if you want a long and happy brush life  Then you can crank up the amps 



> Have a great Holiday Season,
> Jim


Right back at ya,

major


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## Jimdear2 (Oct 12, 2008)

major said:


> Compound  Don't like the sounds of that. They do make what they call seating stones which are really dressing stones. They will shape the brushes to the comm diameter. Something which should have been done at the motor factory. But actual seating and filming requires running time. It is hard to put a load on the motor to get proper brush and comm break-in (seat and film). So running at 12V no load (low current) is usually done. I recently did this with a Warp9 for about 20 hours. Off and on over about a week as I was working on other car parts. Even after that, it is recommended to take it easy on the road for a few hundred miles if you want a long and happy brush life  Then you can crank up the amps
> 
> 
> 
> ...


Major,

Thinking back, seating stones or sticks was what they were called and the guy mentioned different compounds for different brushes. Sounds like something that should be done by someone who has experiance and knows the products.

I guess I'll go with old reliable, jack stands a good battery charger and lots of batteries.

Thanks for the info.
Jim


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## major (Apr 4, 2008)

DavidDymaxion said:


> Berube successfully runs GE interpoled motors. His drag rail is the fastest electric 4 wheeled vehicle in the 1/4 mile, and it's one of his interpoled motors in the rocket bike that set a record for the fastest electric 1/4 mile on it's 3rd pass.


Hi David,

I thought I saw Dennis claim those two motors did not have interpoles. But it is hard to follow that guy and figure out what he talkin' about 

How about you ask him 

major


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## DIYguy (Sep 18, 2008)

Going back to my mention of available space around the inside circumference of the yoke.... obviously, there is only so much of it. How to best utilize it for maximum motor torque and still have enough left to facilitate "canceling interpole fields"....yep, it's a question...lol

So, for pole mass saturation calculations.... what is known? 

How much headroom was left in my 13 motor pole design WRT saturation.. I wonder... and how much could I mill off those puppies without having too little left. I'm sure it is directly related to NI.

I'm relatively sure that the two series coils and original poles in this thing are significantly larger than what 4 coils/poles are in a typical 13" series motor. I say this because 4 such coils would not fit around this yoke (I tried). So, I know I could take off "some" amount of copper.... and some amount of pole material. I guess, the thing is, the motor designers are not modeling these things for EV applications.... so the original designs may be somewhat misleading..... ?? Ya, that could be another question... 

Looking at the Kostov pics... the main pole shoes have a wide surface area close to the armature. The body is slim enough to allow the entire winding to set inside of the "footprint" or "shadow" cast from the "face" of the shoe (if I can call it that... what's it called Major?) This is what I was going to do with mine...Perhaps the NI of the Kostov reduce the saturation problem? The interpole shoes are also laminated...but seem to be much thicker steel and stacked the opposite way.


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## major (Apr 4, 2008)

DIYguy said:


> "face" of the shoe (if I can call it that... what's it called Major?)


Yeah, in motor lingo, the whole laminated piece which is bolted to the inside of the yoke (frame or housing) is called the pole shoe or sometimes the pole piece. The surface of the pole shoe which faces the main air gap towards the armature is the pole face. The part of the pole shoe around which the field coil is wrapped is the pole body. And the parts which extend out from either side of the pole body to increase the pole face surface area are called the pole tips. And even the opposite side of the pole body has a term called "pole at frame".

All of these pole parts enter into the magnetic circuit calculations as well as the yoke and most importantly, the armature. You have to consider all the parts of the magnetic circuit for a good motor design, as well as all the parts of the electric circuit design (field and armature winding) and also the interaction of the two. And then for the brushed DC motor, you have to design a commutator for the system.

major


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## DIYguy (Sep 18, 2008)

DavidDymaxion said:


> Berube successfully runs GE interpoled motors. His drag rail is the fastest electric 4 wheeled vehicle in the 1/4 mile, and it's one of his interpoled motors in the rocket bike that set a record for the fastest electric 1/4 mile on it's 3rd pass.
> 
> John Wayland switched away from Kostov after blowing his up, but I'm not aware of anyone else -- who else switched away from Kostov? I'd like to email them and learn from them.
> 
> ...



From Berube in Sept/10.....
As I told John Wayland who insisted I ran interpole motors the only interpole motor I own is on the bench (was in the truck 2 hrs.ago).The dragster motor is also a series motor 11 inch. I would bet Power to weight ratio says it has outpreformed the Kilacycles 2 motors and the sweet part is without any rebuilding.

Dennis Berube


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## major (Apr 4, 2008)

DIYguy said:


> From Berube in Sept/10.....
> As I told John Wayland who insisted I ran interpole motors the only interpole motor I own is on the bench (was in the truck 2 hrs.ago).The dragster motor is also a series motor 11 inch. I would bet Power to weight ratio says it has outpreformed the Kilacycles 2 motors and the sweet part is without any rebuilding.
> 
> Dennis Berube


Like I told you, it is impossible to figure out what this guy is trying to say.

But I think the only interpole motor is in his new truck, not his record setting dragster or bike.

major


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## DIYguy (Sep 18, 2008)

major said:


> Like I told you, it is impossible to figure out what this guy is trying to say.
> 
> But I think the only interpole motor is in his new truck, not his record setting dragster or bike.
> 
> major


Certainly looks that way. 
Wow, I spent some time on the NEDRA site... jeez these guys don't like each other! Seems like Berube is the odd guy out...??? Him and Wayland seem to bicker a fair bit...lol

What do you think about the comment of zorching being much more unlikely on a larger motor? Brushes being physically further apart being the main reason. Seems logical.....


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## DavidDymaxion (Dec 1, 2008)

Dennis and I just traded some emails. I then got the impression he had removed or modified the interpoles in his 2 earlier motors, but he then clarified the Current Eliminator (fastest electric 4 wheeler) and Rocket bike (fastest electric 2 wheeler) never had interpoles. He also said his current S10 motor does have interpoles and is doing well.

Anyway, I stand corrected on the two fastest motors -- sorry for the misinfo!

I am amazed he can put 300+V on non-interpoled motors.


major said:


> Hi David,
> 
> I thought I saw Dennis claim those two motors did not have interpoles. But it is hard to follow that guy and figure out what he talkin' about
> 
> ...


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## DIYguy (Sep 18, 2008)

DavidDymaxion said:


> Dennis and I just traded some emails. I then got the impression he had removed or modified the interpoles in his 2 earlier motors, but he then clarified the Current Eliminator (fastest electric 4 wheeler) and Rocket bike (fastest electric 2 wheeler) never had interpoles. He also said his current S10 motor does have interpoles and is doing well.
> 
> Anyway, I stand corrected on the two fastest motors -- sorry for the misinfo!
> 
> I am amazed he can put 300+V on non-interpoled motors.


Yes, I talked to Dennis about it last night also. He told me the same thing. I don't know that he would be putting all of that voltage to the motor though. His pack is over 300 volts...but he may be limiting it to the motor perhaps?? 
I have heard that the larger diameter 13" motors will take higher voltage before zorching because of the distance between the brushes on the larger diameter commutator....


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## DavidDymaxion (Dec 1, 2008)

He told me 300V at the motor terminals.


DIYguy said:


> ...I don't know that he would be putting all of that voltage to the motor though. His pack is over 300 volts...but he may be limiting it to the motor perhaps?? ...


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## DIYguy (Sep 18, 2008)

DavidDymaxion said:


> He told me 300V at the motor terminals.


Wow...that is crazy.....


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## DIYguy (Sep 18, 2008)

DavidDymaxion said:


> He told me 300V at the motor terminals.


Wow, that's amazing.....

edit...ooops, sorry...


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## DIYguy (Sep 18, 2008)

Well, after going round and round with this motor.... looks like I am going to take a crack at making it into a decent series-only motor. I have two sets of series coils (one set of 2 from each of 2 compound wound motors.) With the help of u-know-who.... I think I know what I have to do to make this thing work well. I will be removing copper from these coils in order to get a armature to field ratio of 1.62. One set of coils will have 9 turns, the other set will have 6 turns for an average of 7.5 T/C. Opposing coils must have the same number of windings (+/- 1/2), adjacent coils may be different. 

One set was easy to uncover, basically cut the Nomex and peel off. The other was unbelievable. The resin was so hard and thick. Care must be taken to not scratch the wire surface and cause turn to turn shorts. Not a problem when removing turns, you can chisel away at the outside turns. 

The look like this now. . . OK, guess I only took pic of one of them...


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## DIYguy (Sep 18, 2008)

First coil wrapped. I also have a place to dip/bake them when I'm ready.


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## toddshotrods (Feb 10, 2009)

Wow, somehow I missed this whole thread!  Nice read though, I couldn't stop until I got here!  I've been tossed and torn with this issue since I bought my 11" GE Sepex motor. Logic tells me to at least see what it's like manually controlling the field (with a small series controller) at low (48) volts, and then look into series field coils when I get a little more serious.

Can't wait to see how your motor runs!


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## DIYguy (Sep 18, 2008)

I thought I had better make sure of all my connections and coil wind direction before I finish all the wrapping... of course I had three done by this point. I had to temp mount them all back in the yoke and after some bending and clipping etc... I think I can finish up now. I snap a couple pics soon to show what I'm talking about. Just important to keep in mind before you get them all wrapped and dipped since you don't want to have to uncoil some bit to make a connection. This heavy copper is a bear to bend.....


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## DIYguy (Sep 18, 2008)

So, i started working on this motor again recently and thought I would share some progress pics.

Here are the field coils after silver brazing, wrapping and dip and bake.


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## DIYguy (Sep 18, 2008)

I had the frame turned. It was actually very true (unlike some I've seen) and only had to skim the surface.


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## DIYguy (Sep 18, 2008)

Here's the commutator before and after, and the whole armature.


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## DIYguy (Sep 18, 2008)

Here is one of the pole shoes. You can see where I added laminations at each end. These were welded in place and buffed clean on the ends. I had extra shoes from the other motor. The armature had more length than the shoes, so, I've managed to get part of that back. This should translate into more torque I expect.


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## DIYguy (Sep 18, 2008)

Here is the coil set mounted in the yoke. FYI, there is no paint under the pole shoes. . .as this is an important electrical connection.


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## LithiumaniacsEVRacing (Oct 9, 2010)

Very cool thread! I learned a ton. I have heard of some new designs and brushes that will improve your ability to up the voltage is a series motor.


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## jeff mccabe (Feb 23, 2010)

DIYguy,
Thank you for that little snippit ! I was wondering about this. My inner cases had a lot of rust in them, but they were not rusted under the field shoes.

Jeff 





DIYguy said:


> Here is the coil set mounted in the yoke. FYI, there is no paint under the pole shoes. . .as this is an important electrical connection.


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## DIYguy (Sep 18, 2008)

LithiumaniacsEVRacing said:


> Very cool thread! I learned a ton. I have heard of some new designs and brushes that will improve your ability to up the voltage is a series motor.


Hey, thanks. Major was a big help and kept me on track. I'm still learning too. I know about the Helwigs, in fact I started this thread on them last year....http://www.diyelectriccar.com/forums/showthread.php?t=59721. I got a set for my 9".

It looks like the newer designed motors use many smaller brushes. . . ?


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## DIYguy (Sep 18, 2008)

I still have some work to do on this beast, but here it is running the brushes in. It has about 20 hours on it now. Runs nice and smooth. 

Here's a shot of my "little" gem GE 11" also. 

Figure I may as well add a pic of the 9" I did a few years ago... it's still running strong.


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## tomofreno (Mar 3, 2009)

Very interesting thread! Especially since I recently got a copy of Robert Rosenberg's Electric Motor Repair and started studying it. Just stumbled onto the thread and read through it all. So you ended up using the 4 series windings from the two motors to make it a series motor I guess. I would like to pick up a motor cheap to play with like this. Just read in Rosenberg about changing windings for a change in operating voltage or a change in speed. Would be fun to experiment...would need to find sources for magnet wire, insulation, varnish...better study some more first!


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## DIYguy (Sep 18, 2008)

tomofreno said:


> Very interesting thread! Especially since I recently got a copy of Robert Rosenberg's Electric Motor Repair and started studying it. Just stumbled onto the thread and read through it all. So you ended up using the 4 series windings from the two motors to make it a series motor I guess. I would like to pick up a motor cheap to play with like this. Just read in Rosenberg about changing windings for a change in operating voltage or a change in speed. Would be fun to experiment...would need to find sources for magnet wire, insulation, varnish...better study some more first!


Hi Tom,

It was a fun and rewarding project. Yes, I managed to use the two series winding from each motor. I had to stip off some copper to get the armature to field ratio correct. Major was invaluable in this regard. I surely would have screwed it up if it were not for his directions. I did read a lot and learned a lot, but he has a lot of practical as well as theory knowledge. Perhaps the cheapest way to "experiment is to get several "scrap" motors. They are cheap and u can use the materials in them. Buying new materials is crazy expensive. I priced new field coils and I could have bought a new motor for that cost. I have quite a bit of Sil-Fos silver solder left, if you need some.  It's also too expensive. Good luck!


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## DIYguy (Sep 18, 2008)

Well, that's it for the big 13" for now. It's been running for more than a week off and on a bit. No brush advance system or cover bands, but it's nicely run in. 
Luckily I have a second aluminum CE casting and brush assembly to play with. I really like that both end bells are alumiunum. At 321 lbs it's about 45 lbs lighter than the Warp 13". I've seen a few iterations of that beast though. . .so, who knows. 

Now to get the Lenco reverse and GV unit connected.


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## jeff mccabe (Feb 23, 2010)

Hey DIYguy,
I have a question.
What is the best material to use between the field coils and the outer housing.
I bought some 5mil ultum , but the old stuff is 10mil and more of a paper based product ? Here a a few pictures of what im up to.

Thanks, Jeff




























DIYguy said:


> Well, that's it for the big 13" for now. It's been running for more than a week off and on a bit. No brush advance system or cover bands, but it's nicely run in.
> Luckily I have a second aluminum CE casting and brush assembly to play with. I really like that both end bells are alumiunum. At 321 lbs it's about 45 lbs lighter than the Warp 13". I've seen a few iterations of that beast though. . .so, who knows.
> 
> Now to get the Lenco reverse and GV unit connected.


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## major (Apr 4, 2008)

jeff mccabe said:


> What is the best material to use between the field coils and the outer housing.


Nomex 410 

http://www.eis-inc.com/suppliers/dupont-nomex.asp?showcase_no=19680


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## jeff mccabe (Feb 23, 2010)

Thanks Mayor !

Would like to talk to you about the final assembly of my motors. I will send you some private emails soon.

Jeff McCabe





major said:


> Nomex 410
> 
> http://www.eis-inc.com/suppliers/dupont-nomex.asp?showcase_no=19680


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## DIYguy (Sep 18, 2008)

Sorry Jeff, I was away at a hockey tournament since Friday. 

Thanks Major.


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## jeff mccabe (Feb 23, 2010)

Sounds like fun.. 
I had to LMAO a few days ago when a friend showed me a clip from a start of a Ranger game, I think. As soon as they dropped the puck, they just started fighting for 10-15 minutes...to funny !

Jeff


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## DIYguy (Sep 18, 2008)

jeff mccabe said:


> Sounds like fun..
> I had to LMAO a few days ago when a friend showed me a clip from a start of a Ranger game, I think. As soon as they dropped the puck, they just started fighting for 10-15 minutes...to funny !
> 
> Jeff


LMAO, perfect. A good warm up for a game of hockey. It's still entertainment. It's the coolest game on earth.  My boy got to play at the Joe Louis arena. We went to the Wings/Hurricane's game Sat night.


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## DIYguy (Sep 18, 2008)

So, I'm getting ready to wedge this beast into my truck and right now it is in my basement. There is no way I can get get this thing up the stairs other than the way I got it down . . . which is in pieces. I probably could make a lifting frame and get 3 other guys to help me . . but, I've been thinking about shimming the pole shoes. If I'm going to take it apart again, I think I will get the armature checked for balance as well. 

I think it will be a lot easier to place the motor, move it around so I can design and fabricate motor mounts with a couple hundred pounds removed from it. I can have the yoke, end bells only, and still mount the Lenco/gear Vendors on the back.

I'm looking for feedback on armature air gap to pole shoes. I've been doing some research and there is some info out there on the issue but nothing I can find about actually reducing the gap and by how much etc. I'm aware of the ability to increase torque production and improve efficiency. . . but I'm wondering also about negatives. Will a reduced gap have a negative impact on max rpm/volt???

Dennis Berube told me he goes as close as 0.011" . . in some cases. . . after his "machine shop work. I'm probably not going to get any secrets out of him. . 
Right now, mine looks like about 3/16". I'm sure there is plenty of room to move them in . . but I don't know how far at this point.

Next point is with what. I want to use something like shim stock and drill/punch holes for the screws. This way the spacers will be captive and contact entire footprint of shoes for electrical connection to yoke. Make sense??


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## Ziggythewiz (May 16, 2010)

DIYguy said:


> So, I'm getting ready to wedge this beast into my truck and right now it is in my basement. There is no way I can get get this thing up the stairs other than the way I got it down . . . which is in pieces.


I swear I read this identical post like a year ago. Suggestions included a pallet with lots of friends, pallet with skis and a pulley-winch system, and asking Leroy Jethro Gibbs for assistance.


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## Woodsmith (Jun 5, 2008)

DIYguy said:


> So, I'm getting ready to wedge this beast into my truck and right now it is in my basement. There is no way I can get get this thing up the stairs other than the way I got it down . . . which is in pieces.


That is how I brought the tractor up from my basement, built it up and then took it all apart again to bring up.

Both my 12" and 11" motors were carried down to the workshop in bits and then reassembled.
Much of what I have down there got there the same way, including machinery.

That motor/trans assembly is looking good!


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## DIYguy (Sep 18, 2008)

Ziggythewiz said:


> I swear I read this identical post like a year ago. Suggestions included a pallet with lots of friends, pallet with skis and a pulley-winch system, and asking Leroy Jethro Gibbs for assistance.


The point of the post, and the question is not about getting it up the stairs. It's about shimming the pole shoes and armature air gap.


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## DIYguy (Sep 18, 2008)

Woodsmith said:


> That is how I brought the tractor up from my basement, built it up and then took it all apart again to bring up.
> 
> Both my 12" and 11" motors were carried down to the workshop in bits and then reassembled.
> Much of what I have down there got there the same way, including machinery.
> ...


Hey Woody. Being a woodworker... I enjoy reading about your tractor. I think u get as much of a kick out of doing the woodwork as you do making the mechanical stuff. lol

Growing up on a farm, I learned young about figuring out ways to get stuff done with what you have . . and usually that means by yourself.... lol


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## Tesseract (Sep 27, 2008)

DIYguy said:


> The point of the post, and the question is not about getting it up the stairs. It's about shimming the pole shoes and armature air gap.


Dontcha just hate it when a thread goes sideways? 

A smaller air gap between the field and armature generally results in an increase in torque and a decrease in speed for a given voltage * current. The adjustment range is generally a few percent maximum, IIRC.

Making the gap smaller should also sharpen the knee in the saturation curve. That is to say, below saturation the torque increases with the square of current while in saturation it is a linear function of current. I doubt that will have any huge impact on driveability, however.


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## DIYguy (Sep 18, 2008)

Tesseract said:


> Dontcha just hate it when a thread goes sideways?
> 
> A smaller air gap between the field and armature generally results in an increase in torque and a decrease in speed for a given voltage * current. The adjustment range is generally a few percent maximum, IIRC.
> 
> Making the gap smaller should also sharpen the knee in the saturation curve. That is to say, below saturation the torque increases with the square of current while in saturation it is a linear function of current. I doubt that will have any huge impact on driveability, however.


LOL, thanks Jeff. I knew about the increase in torque. I suspected a reduction in rpm. . . I didn't realize or think about the saturation point "sharpening". (Overall efficiency is suppose to be improved also apparently. . which makes sense.) I guess that is to say, it would happen over a smaller current range. . ? Ya, probably not going to be a noticeable point in time. Acknowledging all of this, and applying it to 1/4 mile performance, one would assume some improved performance from the increased torque . . . although, wouldn't the saturation point be effectively shifted to a lower current threshold, assuming the same voltage? This would have a somewhat overall negative effect on performance. yes-no? I suspect the former being more significant than the later . . . otherwise, it wouldn't be pursued by motor builders.

Now the trick is to quantify and put limits on the physical side of it all. Of course too close is risky business . . a place I'm not interested in going.

Some where between where it is now at about 3/16" and the 11 thou quoted by Dennis is the bogey. IF I don't get any thing concrete, I will likely just half what is there now. 

Several of my decisions on this build were based on a lower rpm system. This stems from my wanting to parallel my existing battery therefore exploiting higher current as opposed to a higher voltage component to the power equation. This allows me to keep my charger and other components of the original build. Therefore, this mod, may align with those other stars. Hence the GV decision also.


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## Yabert (Feb 7, 2010)

I reduced the air gap on my 11'' motor last year.



Yabert said:


> I add spacer bellow the polar core (stator poles) to reduce the air gap between armature and stator. From 0.066” stock to 0.035” now. Anyone know what kind of percentage efficiency/torque/advantage that change will do? I see at many places that help, but how much?
> 
> What about this formula: GAP, inch= 0.005+ 0.0003 D+ 0.001 L+ 0.003 V
> 0.005 + (7.375x0.0003) + (4.515x0.001) + (6.76x0.003) = 0.032”


Like you can see, the radius gap was 1/16, so 3/16 (or 3/32?) seem a lot.
I don't perfectly understand the effect of reduce air gap, but I'm interrested to learn. Keep us informed.


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## DIYguy (Sep 18, 2008)

Yabert said:


> I reduced the air gap on my 11'' motor last year.
> 
> 
> 
> ...


Thanks for that data point Yabert. More good info.


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## DIYguy (Sep 18, 2008)

Just wanted to put some closure to this thread. The 13" is in my truck and works real well. It was a fair bit of work with all the copper rework, winding, silver brazing etc. But I learned a lot. A big thanks to Major without whom I would have taken a stab in the dark regarding many issues. Major provided much help off-line to me directly. 
Every once in a while you come across someone who possesses not only the technical knowledge but even more practical experience. . . something that is just so elusive to education . . and that is not a slight to our technical facilities. .. it's just, well, it's just reality. Major is one of those guys. He fills all the gaps.


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## Bowser330 (Jun 15, 2008)

DIYguy said:


> Just wanted to put some closure to this thread. The 13" is in my truck and works real well. It was a fair bit of work with all the copper rework, winding, silver brazing etc. But I learned a lot. A big thanks to Major without whom I would have taken a stab in the dark regarding many issues. Major provided much help off-line to me directly.
> Every once in a while you come across someone who possesses not only the technical knowledge but even more practical experience. . . something that is just so elusive to education . . and that is not a slight to our technical facilities. .. it's just, well, it's just reality. Major is one of those guys. He fills all the gaps.


any videos of the truck in action?


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## DIYguy (Sep 18, 2008)

Bowser330 said:


> any videos of the truck in action?


No, sorry. Not yet. But I will see what I can do going fwd. Maybe time for a Go-Pro cam.


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## rochesterricer (Jan 5, 2011)

Hell, I bet even just a burnout video captured with an iphone would keep most of us happy


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## Ziggythewiz (May 16, 2010)

*would make most of us happy.

Then we'll want to see more


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## DIYguy (Sep 18, 2008)

Ziggy is right Rochester..... u lot wouldn't be happy for long... lol


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