# advancing timing on a forklift motor



## Tristar500 (Jul 9, 2008)

Looking for advice for the amount of advance to take a 36 volt 9 inch forklift motor to 120 VDC.
The motor can be timed by rotating the entire rear bearing and brush assembly and re-drilling the end assembly.


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## major (Apr 4, 2008)

Tristar500 said:


> Looking for advice for the amount of advance to take a 36 volt 9 inch forklift motor to 120 VDC.
> The motor can be timed by rotating the entire rear bearing and brush assembly and re-drilling the end assembly.


Hi Tristar,

Depends if you start on neutral, which is usually the case with a reversible forklift motor. I think Jim Husted would tell you to go 10 degrees. We'll see if chimes in on this.

Regards,

major


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## Tristar500 (Jul 9, 2008)

Anybody have any idea at all how far to advance the timing? I'm going from 36 VDC to 120 VDC. I'd assume the 36 VDC forklift motor was neutraly timed to start with.


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## ww321q (Mar 28, 2008)

Go through the "using a forklift motor" thread . It has the info you want posted by Jim Husted . I think 10 deg is right for 120 volts . 0 deg. advance , the center of the brush is even with the field coil bolts . J.W.


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## Coley (Jul 26, 2007)

At the Ogle County Energy Fair, I spoke with a fellow from Iowa, that has the job of testing motor brushes.

His findings have been that he can get better performance with a different brush compound than advancing the brushes.

When I told him that I was using a Baldor fork lift motor, he told me that that was one of the hardest motors to get good performance out of.

That made me feel swell.....

He claimed that most motors will do better and last longer with a better quality brush than the OEMs, that they came with.

Like an idiot, I didn't get his business card, as I thought I would get to talk to him later.

I am trying to track his business down now. I don't know if Jim H has knowledge of him or not.


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## ww321q (Mar 28, 2008)

He may not understand what it is that we are trying to do by advancing the brushes . Changing brush compound would change the wear characteristics and possibly reduce the amp draw .It may also reduce the chance of flash over too . But I doubt that it would change the torque or horsepower at a given RPM . That's the other reason to advance brushes . A good brush and advancing them may be the way to go J.W.


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## Qmavam (Aug 17, 2008)

ww321q said:


> He may not understand what it is that we are trying to do by advancing the brushes . (snip) change the torque or horsepower at a given RPM . That's the other reason to advance brushes . A good brush and advancing them may be the way to go J.W.


Would you please give me some general information on what you are trying to do when you advance the brushes. Is this only when running a motor above specified voltage? 
A newby on the learning curve,
Qmavam


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## major (Apr 4, 2008)

Qmavam said:


> Would you please give me some general information on what you are trying to do when you advance the brushes. Is this only when running a motor above specified voltage?
> A newby on the learning curve,
> Qmavam


Hi Qmavam,

Advance for a motor is shifting the brushes towards the direction of rotation slightly. The best position for the brushes to contact the commutator is midway between the north and south poles, or neutral. However when the motor is under load, the magnetic field of the armature distorts the main field (from the stator) and shifts it so the "magnetic neutral" is no longer aligned with the mechanical neutral. This shift causes induced voltage in the armature coils as they exit the brush and cause arcing.

One can compensate by shifting the mechanical position of the brushes to align with a "best guess" to where the magnetic neutral will be and reduce the amount of arcing under load. This arcing increases with voltage, current and speed, or any two, or any one of the three. That is why I say "best guess", because the EV traction motor is always changing voltage, speed and current as it accelerates. So, rules of thumb, and Jim Husted's advice are what most rely on.

Realize that this brush shift is the other way for opposite direction of rotation. That is why reversible motors are almost always set to mechanical neutral. Also, the brush shift is opposite for a generator than a motor. Why regeneration isn't so great with advanced motors. These problems can be overcome by using motors with interpoles, but this is rare in EV motors that people can afford.

Hope this helps,

major


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## ww321q (Mar 28, 2008)

major said:


> Hi Qmavam,
> 
> Advance for a motor is shifting the brushes towards the direction of rotation slightly.


 I believe Advancing brush timing would mean before 0 timing . That would be opposite of rotation . J.W.


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## major (Apr 4, 2008)

ww321q said:


> I believe Advancing brush timing would mean before 0 timing . That would be opposite of rotation . J.W.


J.W.

Yes, of course. Sorry if that was not clear.

major


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## ww321q (Mar 28, 2008)

I'm glad this came up because I was thinking about advancing mine . The way the brush plate mounts keeps me from moving it in the ce plate . I forgot about drilling the case . Da! I hate getting old ! LOL !  J.W.


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## 1clue (Jul 21, 2008)

I have a question relating to this.

I'm a n00b here, and have been doing a lot of research on the side. However, I've only researched AC conversions so this issue does not come up.

Is this timing advance done in order to compensate for what would be slippage under load in an AC induction motor?


I can't see why else you would need to do this.

Thanks.


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## Tristar500 (Jul 9, 2008)

I'm assuming that "advancing" the timing means rotating the brushes of the motor in the same direction around the armature as the armature spins. (running in forward of course)



major said:


> J.W.
> 
> Yes, of course. Sorry if that was not clear.
> 
> major


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## ww321q (Mar 28, 2008)

You advance the brush . That means in advance or before . It would be opposite of rotation that way the brush meets the com bar sooner . I'm sure someone could explain how it effects the field in relation to the armature . I can't . cause my brain don't do that ! LOL! J.W.


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## major (Apr 4, 2008)

1clue said:


> I have a question relating to this.
> 
> Is this timing advance done in order to compensate for what would be slippage under load in an AC induction motor?
> 
> Thanks.


No. This is different. AC motors are timed with the frequency and phase angle by the controller. Slip in the ACIM is necessary to induce rotor currents.

Regards,

major


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## buzzforb (Aug 16, 2008)

I have a motor question that follows alog the same lines but is a little different. I am looking at industrial, inverter duty motors(Marathon Black Max - 30hp) as a possible use in an ev conversion. How much increases performance can i get out of this motor with a quality controller and possible addition of water cooling.


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## major (Apr 4, 2008)

buzzforb said:


> I have a motor question that follows alog the same lines but is a little different. I am looking at industrial, inverter duty motors(Marathon Black Max - 30hp) as a possible use in an ev conversion. How much increases performance can i get out of this motor with a quality controller and possible addition of water cooling.


Hi buzz,

You got a pretty wide open question. It all depends on how cleaver you are and how much money you are willing to spend. It is possible to go ten times the power, but it is difficult to say the least. And expensive. If you have that amount of fundage, you might as well buy a high power AC system and save yourself the trouble.

Back to earth, you can maybe do twice the frequency (120 Hz) and overload the motor (like twice the current) and see 2 to 3 times the rated power. You will need to tackle the thermal management issue if you run above rated power for long. Beyond that, you need to look at motor rewinds, balance and bearing issues. This says nothing about the inverter/motor compatibility, which is not trivial.

Regards,

major


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## buzzforb (Aug 16, 2008)

Major,
Thank you for responding to my question. I know it was somewhat general in nature, I was just hoping for a response. The controller will be a custom made version of the circuit cellar design. The compnanents will consist of Microchip processors and powerex IGBT's. Although i have not worked out all the details yet, i think it should have a great deal of flexibilty as well as usuability. On the subject of the motor, running at 120Hz will be doable if i am able to cool the motor more efficiently? The motor is rated at 1800 RPM's but has 3600listed as its max. If i could get 2 to 3 times the power based on these changes that would probably suffice, But!!! Do you hvae an idea of how much rewinding would cost. I am assuming this would allow for increased current into the motor, which translates into more power. Also, is chaging bearing s something that i could do? I was cosidering making a whole new enclosure so that i could incorporate water cooling and i could address the bearing issue when this is done. Let me know what you think? once again, thank you for the reponse.


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## major (Apr 4, 2008)

buzzforb said:


> Major,
> But!!! Do you hvae an idea of how much rewinding would cost. I am assuming this would allow for increased current into the motor, which translates into more power. Also, is chaging bearing s something that i could do? I was cosidering making a whole new enclosure so that i could incorporate water cooling and i could address the bearing issue when this is done. Let me know what you think? once again, thank you for the reponse.


Hey buzz,

I have no idea of your capabilities and resources. So I can not say what you can or cannot do. As for rewinding, figure about the same as the cost of a new motor. That's why these size motors are not often rewound. And you'd have to supply the revised winding pattern to the winder. Again, like I said, you pay for all that; you might as well put out the big bucks for a high power AC package to start with.

Regards,

major


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## 1clue (Jul 21, 2008)

I have a suggestion.

Find a smaller motor you don't care about but could use. Take it apart, cut the copper off and rewind it yourself. See what happens, and using that as a reference figure out if you're willing to try it on the bigger motor.

My dad is retired, and picks up electric motors from the scrap yard before they get cut up for the metals, usually for the price of unsorted scrap metal. He takes them apart and fixes them, usually it's something easy like one wire burned or bad brushes. Sometimes he rewinds the entire motor. I haven't done that yet, but I've started experimenting with small RC airplane motor kits to get the hang of it. I don't think I would have much trouble rewinding a motor, but it would take time.

Rewinding a motor, in my understanding, requires the amount of copper wire you need (magnet wire, which is insulated) and possibly some sort of resin to keep the wires in place, and then a small fee to put it in the oven to cure the stuff that keeps the wires in place. If you want a brush motor, you might be stuck replacing a commutator. I don't know if you can get those separately, I would check first.

If you are worried about the price of rewinding, then maybe the do-it-yourself method is for you. You can search on electric motor repair, find out how much magnet wire costs and the resin they use, and the fee for putting your size motor into their oven to cure it. Then it's the price of materials and your labor.


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## buzzforb (Aug 16, 2008)

The Marathon Black Max motor I am looking at will run about 2,300. Compared to a high end system from Metric Mind, I still have a lot of wiggle room for custom alterations. I am thinking i can improve the performace quite a bit with just the controller and liquid cooling, but if rewinding is possible and bearing change is possible, i can't imagine it costing as much as a metric mind setup of equivalent size. If i am wrong please let me know since i am also just trying to figure this all out before diving in. Here is the link to the motor.

http://motors.automationdirect.com/Marathon/blackmax_specs.html


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## 1clue (Jul 21, 2008)

It might not have come across the way I wanted. When I said get a smaller motor, I meant something like a washing machine or ceiling fan motor. Just to see what's involved in rewinding a motor.

It would really be a drag if you dove straight into a huge motor that it cost a lot to get, and then trash it when you made a mistake, or discover it's a whole lot more work than you were thinking.


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## major (Apr 4, 2008)

buzzforb said:


> If i am wrong please let me know since i am also just trying to figure this all out before diving in.


Yeah, buzz,

Like I said, I don't know ya. But I'd venture to say you're diving into the deep end and don't know how to swim. But you could be an EE with an uncle who has a motor repair business. And that motor is 575 pounds! What did you have in mind to convert, a bus?

Regards,

major


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## buzzforb (Aug 16, 2008)

I was not planning on jumping in to the deep end so to speak. Just trying to understand the different aspects of this ev business. Everything i do will be done in a smaller scale to begin with, like a motorcycle perhaps. That being said, I am trying to educate myself in whatever way i can. I would think members of this forum, having dealt with big companies on issues like batteries and motors, would be more of an open source for information. I understand being careful about what is said and the kind of information that is spassed on, but it seems like every once in a while, i hit this big invisible wall when it comes to getting help. I think both of you for your input and mean no disrespect. Just looking for answers to questions in what i think is the best source for those answers.


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## buzzforb (Aug 16, 2008)

I was assuming, perhaps incorrectly, that a large part of the weight of that motor is coming from the casing. Don't know for sure, just guessing really. Thats why i am asking.


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## 1clue (Jul 21, 2008)

buzzforb said:


> I think both of you for your input and mean no disrespect. Just looking for answers to questions in what i think is the best source for those answers.


From my end of things, I've recommended equipment for somebody on a different site before. Several times actually, but one time somebody misunderstood what I was saying and I didn't get back on it right away. He wound up buying a whole lot of the wrong stuff that same night, and I felt pretty bad about it because I knew he wasn't "on target" so to speak.

When I clarified my motor winding suggestion, it was to prevent a potential mistake. As well, keep in mind I'm a n00b here. I know about motor winding only from books or indirectly, so I'm a bit hesitant to say go ahead and do it, you know what I mean?

If this comes across as being jumpy somehow, then I apologize. I intend my idea to be just that, something to be considered by you, in your current circumstances. If you up and bought a 600 lbs motor and chopped it up, that would be a disaster especially if that was your first motor winding attempt and something went horribly wrong.


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## OHM (Jun 30, 2008)

buy a second hand equivalent to the black max one and then look at moddin it, there are plenty of them around.


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## buzzforb (Aug 16, 2008)

Will do gentleman. Thanks for the help. I might be tuggin at your sleeve for some more help in the near future.


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## Hi Torque Electric (Dec 23, 2007)

Hey all

Sorry I've been absent for so long but I've been busy and have been coming home feeling like an 800 pound gorilla beat me with 9" pipe 

In general 10 to 12 degrees is about as general an advancement as can be stated. Any more and the motor looses properties, and less doesn't get the max voltage limit most would like. No idea what any motors "max" limit would be either as they're all wound a bit different.

Coley:
Never heard of the guy, and brush materials can make a difference in commutation, but will not effect a motor like advancement will. If the brushes are not in line with the field magnetics they'll arc regardless of what they're made of IMO. I've heard of people spending 500.00 on a brush set, but (again IMO) drilling and tapping 4 holes gives more bang for buck. If you're not planning on racing (and your brushes aren't solid carbon or copper) you'll be fine. Most motors these days use an electrograghitic compound that works well EVen at the higher voltages. I'd almost bet the guy was looking to make a sale, or just wanted to sound like he knew what he was talking about, and I'll put this under the "take it with a grain of salt" tpe advise.

Hope this helps.
Jim Husted
Hi-Torque Electric


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## Drizzle (Jun 17, 2008)

Okay -- I know this sounds like beating a dead horse, but I'm gonna raise this question ONE MORE TIME, so I don't blow the motor I'm so happy to have found inexpensively...

When we "ADVANCE" the brushes, we're going to turn the brush assembly IN THE *OPPOSITE* DIRECTION of the rotation of the commutator they're 'brushing" against... Is this right? This is so the brush meets the commutator bar the requisite 10-12 degrees BEFORE it would if the brushes where still in the NEUTRAL location -- I am understanding this right?

I'm hoping Jim is still around to chime in with this -- but thanks to anyone with more experience (and that wouldn't take much at this point) than I have. 

Cheers,
Drizzle


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## 3dplane (Feb 27, 2008)

Drizzle!
You got it right! You will also be able to tell your successful advancement by higher rpm. Say you test run it on 12V and your ear is honed in on the rpm, after advancing you should experience higher rpms.
Barna


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## champy (Nov 24, 2008)

So. . . not to be dumb, but I haven't been able to locate a straightforward answer to this question: Advancing the brushes on a motor will increase the RPM's per-volt, yes? So, if my forklift motor turns 855 RPM's at 36 volts, it should turn faster at 36 volts by advancing the brushes? Is there a formula to determine that, say, a 10-degree advancement would yield a certain percentage more speed? Forgive me if this is covered elsewhere, I've searched the forums and Google and not been able to find a straight answer. Thanks!


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## Kirk_Wallace (Nov 20, 2008)

This thread has me thinking about motor timing and here is some of my thinking.

Lets consider a two pole motor that has voltage on it, but is not turning. Let's say the N and S stator poles and brushes are on the horizontal plane. The coils on the top half of the armature are full on N, and the bottom half is S. Visualize a circle with a horizontal line through it. The diameter of the circle is the armature field strength the color is the polarity, lets say red and blue. the top half is blue. We have a circle because all coils are are full on, either red or blue.

Now let's start to rotate the armature, let's say clockwise. as each coil changes from N to S and S to N the field for each changing coil collapses and builds in the opposite field direction, which takes time. So instead of the top and bottom half of the armature being full on. there are regions where the field is changing. Now we don't have a circle anymore. On the left, the bottom red bleeds up into the blue and the outside of the circle dips to the center and then out again. On the right side the blue bleeds down into the red. The areas where the field is bleeding to the top or bottom half, produces a negative torque. Advancing the brushes, rotates the field circle so that all of the top half is again blue and the bottom red. If you advance too far, you will start getting negative torque regions on the opposite sides.

I wonder if this is actually the case?

I would think a voltage circle would look very different.
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Kirk
http://www.wallacecompany.com/machine_shop/


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## booksix (Aug 26, 2008)

There is a thread I was reading recently. It had a quote from Jim Husted and I want to say he said 10 degrees for 144 and 13 degrees for 156. May be wrong but I'm just saying you may want to dbl check before drilling. I'll try to find that info I 'think' I remember seeing!


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## booksix (Aug 26, 2008)

http://www.diyelectriccar.com/forums/showthread.php?t=25150


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## enganear (Jun 16, 2008)

booksix said:


> There is a thread I was reading recently. It had a quote from Jim Husted and I want to say he said 10 degrees for 144 and 13 degrees for 156. May be wrong but I'm just saying you may want to dbl check before drilling. I'll try to find that info I 'think' I remember seeing!


As another point of reference, Jim recommended 13 degrees for my 11" GE Hyster forklift motor at 144VDC. Diameter must also be a factor.
Stephen Chapman


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## Guest (Jan 1, 2009)

Advancing will allow you to run higher voltages without arcing. It is not meant to give you more rpm's but in effect with more voltage you will have higher rpm's and with the motor advanced you can safely run your 144 volts or 120 volts. You need to have a look inside the motor because many motors have adjuster plates within and don't require you to move and re-drill the end plate. My old Baldor motor had an adjustable advance plate and allowed me to make that adjustment. Jim Husted helped me on that one. He is the main Guru of motors and you really need to pour through his site. He is a very busy man and does not have time to answer all the questions but have a look inside the brush end and you may just have an a way to adjust your timing and if so it will make your life real simple. You will be able to fine tune once you are up and running. Advance enough to stop any arcing for the voltage you want to run.


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## Woodsmith (Jun 5, 2008)

Just digging up an old thread to understand more about brush advance.

If I understand correctly, advancing the brushes allows more voltage hence more speed hence more power.

But advancing the brushes stops the motor being much use if it is reversed as the brushes are then really retarded a lot.
Does this matter if it is just to reverse the vehicle for parking etc as in general use or would it cause motor/controller damage?

Also, would there be any advantage in making up a variable advance brush carrier that was, say, advanced manually or by a servo or some centripetal fly weights as in an ICE distributor? I was thinking that maybe an advanced motor could be reset to zero for reversing and slow speed use and advanced as speed is increased.
_OK, Found answers to this one on other threads. _

Lastly, if I was to acquire a preused motor from a breakers yard, how would I tell if it was set to neutral and wasn't already advanced either by a previous user or from the factory?

Thank you.


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## Tesseract (Sep 27, 2008)

Woodsmith said:


> ...
> Lastly, if I was to acquire a preused motor from a breakers yard, how would I tell if it was set to neutral and wasn't already advanced either by a previous user or from the factory?
> ...


One simple method that works most (every?) time is to see if the actual brush is directly in line with the bolts that hold a field coil. Usually there are 2 (not so good) or 4 (good) field coils and brush assemblies.


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## Woodsmith (Jun 5, 2008)

Great, thanks. That sounds quite simple then.


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