# Ideal motor for the Zilla...?



## Bowser330 (Jun 15, 2008)

you should read the blog of Mr.Wayland the owner/builder of the white zombie, he had a 11" kostov before he had siamese 8's....that should tell you something about which one to choose...

The kostov motor has interpoles so it can handle higher voltage, a high voltage system requires less AHs to produce the same amount of power...less amp draw will help to reduce the voltage sag of your pack keeping you more effiicient in a way..

Kostov's can handle upto 300V+ where as a Warp-11 can only handle about 160V...

The Kostov does have weaker internals and probably couldnt handle the 1000A repeated abuse you could throw at the Warp-11". However, you woul really only need 500-600A to get the same amount of power...and the Kostovs higher voltage would allow you to pull 500-600A at a higher RPM than with a lower voltage system.


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## CroDriver (Jan 8, 2009)

Thanks for your reply.

I can't find the mail of plasma boy on his site... Have you got it?

EDIT: Found it


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## DavidDymaxion (Dec 1, 2008)

Here's yet another way to look at it:

I assume you have a Zilla 2k, and will be going with the max voltage the Zilla can handle.

You could do 2 Warp 11 motors in series, so each would get 1/2 Voltage but full amps. This would give you more torque at low RPM.

You could also do 2 Kostov motors in parallel, so each would get full voltage but 1/2 Amps. This would give you more high rpm power. This would also tend to heat the motors less (less current), but OTOH the Kostovs can't take as much current abuse as the Warps.

Of course, you could do parallel/series switching with either motor.

Mad scientist suggestion: Buy one of each. 

Yet another suggestion: Buy a 13 inch GE from Berube. He does NEDRA record setting performance with one, with a 2900 pound (1300 kg) truck.



CroDriver said:


> Hi guys.
> 
> I just became a proud owner of a high voltage Zilla controller
> 
> ...


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## CroDriver (Jan 8, 2009)

DavidDymaxion said:


> Here's yet another way to look at it:
> 
> I assume you have a Zilla 2k, and will be going with the max voltage the Zilla can handle.
> 
> ...


Would't two motors be less efficient? I want as much power as possible. I think that it would be better to use 2 kostov's in parallel to get more power at high RPM because I believe that in any case there would be to much torque at low RPM's for the tires.

What about that 13 GE motor? Would it be better than two motors? I think that the Kostov 13" has an integrated parralel/series switch


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## CroDriver (Jan 8, 2009)

Btw. It's not the 2K:

http://www.evcomponents.com/ProductDetails.asp?ProductCode=Z1K-HV


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## DavidDymaxion (Dec 1, 2008)

Yes, two will be less efficient, but only slightly with motors already that big.

One reason many of the racers use 2 (or 3, or 4) motors is there aren't many DC motors available in the big sizes.

Sometimes 2 motors are used for packaging reasons, such as putting the motors in the driveshaft tunnel.

The Kostov 13 incher listed a rather low max rpm.

Wayland and Berube both are among the quickest street legal electrics. Wayland uses 2 motors, Berube a single GE 13 inch.


CroDriver said:


> Would't two motors be less efficient? I want as much power as possible. I think that it would be better to use 2 kostov's in parallel to get more power at high RPM because I believe that in any case there would be to much torque at low RPM's for the tires.
> 
> What about that 13 GE motor? Would it be better than two motors? I think that the Kostov 13" has an integrated parralel/series switch


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## Bowser330 (Jun 15, 2008)

Two kotovs setup siamese style (Wayland) would be the best bet! you wouldn't even require series parallel shifting....

With the voltage of each motor at 300V you could run 500A through each motor and ignoring any voltage sag you would have 150kw at each motor = 200hp x 2 = 400hp....

your 1000A controller will be able to handle the 500A for each (x2 - 1000A) and the Kostovs should be able to handle 500A each without a fuss...

how much to warp 11s cost? There is a vendor on the boards that sells 11inch Kostovs for 2K$ each... thats pretty pricey, however considering the performance level its deal...

what you could do is buy one 11inch kostov run 300V and 1000A through it and then buy another one if you feel you want more....


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## Bowser330 (Jun 15, 2008)

sorry i sound to excited, its just a dual kostov setup has been in my mind for awhile...


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## CroDriver (Jan 8, 2009)

Bowser330 said:


> Two kotovs setup siamese style (Wayland) would be the best bet! you wouldn't even require series parallel shifting....
> 
> With the voltage of each motor at 300V you could run 500A through each motor and ignoring any voltage sag you would have 150kw at each motor = 200hp x 2 = 400hp....
> 
> ...


I think that this would be the best option... I contacted Kostov. I will have to wait 10 weeks for the motors...


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## david85 (Nov 12, 2007)

Warp has upped the rating of their motors to 192V recently.....


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## Bowser330 (Jun 15, 2008)

thats good to know...192V...question still is...where are the controllers to support the extra voltage!!


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## CroDriver (Jan 8, 2009)

Bowser330 said:


> Two kotovs setup siamese style (Wayland) would be the best bet! you wouldn't even require series parallel shifting....
> 
> With the voltage of each motor at 300V you could run 500A through each motor and ignoring any voltage sag you would have 150kw at each motor = 200hp x 2 = 400hp....
> 
> ...


That's exactly what I've done...



Dual 11"


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## Bowser330 (Jun 15, 2008)

CroDriver said:


> That's exactly what I've done...
> 
> 
> 
> Dual 11"


Please explain more CroDriver.... 

Dual 11" warp? Dual 11" Kostov?

Are they connected siamese or are they two seperate axels?

What controller(s) are you using?

What max voltage are you using?

What batteries are you using?

What type of range are you getting from your pack?


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## CroDriver (Jan 8, 2009)

Hi Bowser



Bowser330 said:


> Please explain more CroDriver....
> 
> Dual 11" warp? Dual 11" Kostov?


Kostov



Bowser330 said:


> Are they connected siamese or are they two seperate axels?


I think that they are just two motors on one shaft. What's the difference if the shaft is in one piece or two? 




Bowser330 said:


> What controller(s) are you using?


Zilla 1K HV




Bowser330 said:


> What max voltage are you using?
> 
> 
> What batteries are you using?


ThunderSky LiFePO4 100Ah X 111 cells = 355V nominal





Bowser330 said:


> What type of range are you getting from your pack?


I don't know. The parts will be sent from America to me (Croatia) this week. I expect that the car should be finished till end of summer.

The battery pack will have an capacity of 35kWh. That should be enough for 200 km range


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## Bowser330 (Jun 15, 2008)

AMAZING!

What donor car are you using?

Are you keeping the transmission?

Running the kostovs at 300V you wont need much amerage which will mean better efficiency through less voltage sag and less waste heat....

You also may not need to change gears at all since the higher voltage will help to flatten out the power curve and with so much torque available at lower rpms...


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## CroDriver (Jan 8, 2009)

Bowser330 said:


> AMAZING!
> 
> What donor car are you using?
> 
> ...


Thanks 

First I wanted to convert my BMW that I was using for drift races.

http://www.diyelectriccar.com/forums/showthread.php/bmw-bi-moto-ev-project-28287.html

Because this project got pretty pricey I want a good and modern looking car so I decided for a Mazda RX-8.




They have Wnakel engines that broke pretty often so an used car won't be to expensive. I will purchase a car in a few weeks. 

I will use a direct drive setup. I think the same way as you do about this.

355V X 1000A = 355 kW 

355 kW - voltage sag and efficiency looses should be around 250 kw = 340 hp 

Yeah


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## DavidDymaxion (Dec 1, 2008)

Oh yeah, your car is going to be one awesome machine! I think the RX-8 is a beautiful car.

Be sure you sit in an RX-8 with a helmet on, it has less headroom than average. The rear seats are for cheaper insurance only. 

Will the RX-8 rear end be up to electric amounts of torque? The rotaries made good power, but were not known as torque monsters. Can you get other gear ratios for it?


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## CroDriver (Jan 8, 2009)

DavidDymaxion said:


> Oh yeah, your car is going to be one awesome machine! I think the RX-8 is a beautiful car.
> 
> Be sure you sit in an RX-8 with a helmet on, it has less headroom than average. The rear seats are for cheaper insurance only.
> 
> Will the RX-8 rear end be up to electric amounts of torque? The rotaries made good power, but were not known as torque monsters. Can you get other gear ratios for it?


350 kg of lithium is getting in the trunk so I don't think that there will be a problem. Besides that, I'm one of the top drift race drivers in my country  I love drifting cars and my intention is to build the first electric drift car.

I think that there are a lot of aftermarket parts for the RX-8 available, including diffs. The driveshaft is made of carbon fiber, the differential can take over 650 hp, a lot of torque and is a LSD (Limited Slip Diff). 

I hope that the whole motor(s) will fit in the gearbox tunnel because of the shape of rotary engines. That would be great


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## Bowser330 (Jun 15, 2008)

will you be using the car for difting only?

will you also drag race the car to get a 1/4 mile, 0-60, etc stats?

Please keep us posted and updated on your progress.


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## rallyshark (Sep 19, 2008)

Yes, definitely keep us updated on this setup! I am thinking about the same setup, just with a different battery configuration.

I'll definitely want to know how it goes.


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## Salty EV (Jun 8, 2009)

Any progress?


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## CroDriver (Jan 8, 2009)

Salty EV said:


> Any progress?


Yep, you can see it here:

http://www.diyelectriccar.com/forums/showthread.php?t=28287&page=12&highlight=moto


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## Qer (May 7, 2008)

CroDriver said:


> Yep, you can see it here:
> 
> http://www.diyelectriccar.com/forums/showthread.php?t=28287&page=12&highlight=moto


No, we can't. PhotoBucket doesn't like us. 

You might want to add the pics as attachments instead. You can still link them into the text as well if you like.


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## CroDriver (Jan 8, 2009)

Qer said:


> No, we can't. PhotoBucket doesn't like us.


Photobucket 

I always forget to pay for the pro version... I'll do that tomorrow morning.



Qer said:


> You might want to add the pics as attachments instead. You can still link them into the text as well if you like.


I hate to admit it but it's easier with photobucket


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## bipole (Sep 8, 2009)

Kostov now has the saimese 11's on their website, $4000 usd. 400 vdc.

http://kostov-motors.com/tractionmo.../seriesdcmotorsforelectricvehicleconversions/


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## Qer (May 7, 2008)

bipole said:


> Kostov now has the saimese 11's on their website, $4000 usd. 400 vdc.
> 
> http://kostov-motors.com/tractionmo.../seriesdcmotorsforelectricvehicleconversions/


AWESOME! That one in a Cherokee 4x4! 

Although I think I'll wait until I know if Tesseract and Seb's gonna blow up the 11" too...


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## bipole (Sep 8, 2009)

Qer said:


> AWESOME! That one in a Cherokee 4x4!
> 
> Although I think I'll wait until I know if Tesseract and Seb's gonna blow up the 11" too...


 
Keep us posted, I'll be ready for a motor or two for the GTM by the end of the year. Really interested in the Soliton as well.

What is the weak point in the Kostov 11?


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## Tesseract (Sep 27, 2008)

bipole said:


> What is the weak point in the Kostov 11?



Good question... one that is expensive to answer! If the 11" is anything like the 9"/144V we just torched, then I'd say the field windings (specifically, the spot welds that join them together) are the weak links. The brushes seem to tolerate high volts and amps quite well, but the connections are less robust than in the warp motors (after all, they are wound for higher voltage/lower amperage) so I wouldn't expect them to last as long as the WarP under the same conditions.

The 11" looks to be a better motor all around from the outside, but it makes the same funny "varnish not quite cured" smell whenever its been ridden hard and hung up wet (hot?).


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## CroDriver (Jan 8, 2009)

I would say that the efficiency is a weak point too.



bipole said:


> Keep us posted, I'll be ready for a motor or two for the GTM by the end of the year. Really interested in the Soliton as well.
> 
> What is the weak point in the Kostov 11?



I'll pay the deposit for the GTM tomorrow


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## Plamenator (Mar 6, 2009)

Well, if you compare the Kostov motors to non-interpoled ones there are several trade-offs.
Having interpoles reduces the space available for the main windings. Hence it is my guess that the Kostov windings use smaller copper conductors than a comparable warp motor without interpoles.
The negative consequences of this are twofold:
1)Less capability to handle apm overload
2)Less efficiency while being 2-3x overloaded
This is absolutely normal.
The positive consequence of course is the ability to endure high voltage (192-220V at least subject to rpm staying below 6000).
Testing our motor at 100V+1000A is hitting its weakest point and comparing that to warp's strongest one which is not entirely correct (to be fair Tesseract does admit this in his posts).
A more representative test would be at 192V but up to now I have not found any reliable data for warps in order to make a comparison.


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## Bowser330 (Jun 15, 2008)

So is it fair to compare each by its strongest attribute then?...Warp with its amperage tolerance and Kostov with its voltage tolerance... 

Warp-11 with 144V and 1000A

vs

Kostov 11 with 288V and 500A


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## DavidDymaxion (Dec 1, 2008)

Tesseract: Many thanks for getting great real world data! I hope that isn't too expensive for you, though.

My Kostov was pretty stinky the first time I warmed it up, but I have yet to smell it again despite getting it pretty hot testing it on the Salt Flats. My motor was extensively reworked by Randy of http://www.canev.com (but I don't think he does Kostovs any more). It might have been Randy's varnish and not the original I was smelling. 


Tesseract said:


> Good question... one that is expensive to answer! If the 11" is anything like the 9"/144V we just torched, then I'd say the field windings (specifically, the spot welds that join them together) are the weak links. The brushes seem to tolerate high volts and amps quite well, but the connections are less robust than in the warp motors (after all, they are wound for higher voltage/lower amperage) so I wouldn't expect them to last as long as the WarP under the same conditions.
> 
> The 11" looks to be a better motor all around from the outside, but it makes the same funny "varnish not quite cured" smell whenever its been ridden hard and hung up wet (hot?).


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## bipole (Sep 8, 2009)

CroDriver said:


> I'll pay the deposit for the GTM tomorrow


Nice! Good to have company.

I'm fitting the body right now. The build should go a bit faster for you, I didn't commit to electric until just recently so I spent quite a bit of time on wiring and a little on cooling system that is not needed for the non-explosion-type of motorvation.


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## Plamenator (Mar 6, 2009)

Bowser330 said:


> So is it fair to compare each by its strongest attribute then?...Warp with its amperage tolerance and Kostov with its voltage tolerance...
> 
> Warp-11 with 144V and 1000A
> 
> ...


 
If you are aiming to get the same power, amps at 288V should be around 450-460 due to the higher efficiency of the Kostov at 500A vs 1000A for warp (warp is more efficient amp for amp but 500vs1000 is quite a difference ).
Now that you have 1000A tests at 100V, you can also do 250A at 192V for 60min for both. I think this will be interesting.
In this way there is no need to destroy the motors - just measure ambient temp & collector temp at the end.
By the way, we have a new FAQ section which you may find useful:
http://kostov-motors.com/faq/


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## DavidDymaxion (Dec 1, 2008)

Plamenator -- that FAQ is awesome! Thanks for posting the link.


Plamenator said:


> If you are aiming to get the same power, amps at 288V should be around 450-460 due to the higher efficiency of the Kostov at 500A vs 1000A for warp (warp is more efficient amp for amp but 500vs1000 is quite a difference ).
> Now that you have 1000A tests at 100V, you can also do 250A at 192V for 60min for both. I think this will be interesting.
> In this way there is no need to destroy the motors - just measure ambient temp & collector temp at the end.
> By the way, we have a new FAQ section which you may find useful:
> http://kostov-motors.com/faq/


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## Tesseract (Sep 27, 2008)

Plamenator said:


> ...
> Testing our motor at 100V+1000A is hitting its weakest point and comparing that to warp's strongest one which is not entirely correct (to be fair Tesseract does admit this in his posts).
> A more representative test would be at 192V but up to now I have not found any reliable data for warps in order to make a comparison.


I totally agree, Plamen, that a fair test of the two motors would be equal kW but with voltage/amperage levels more appropriate to each. 

That said, EVnetics makes controllers, so that is what I test with our duno, not the motors, per se. The motors are simply tools that I use to evaluate the Soliton1 - their performance relative to each other is merely incidental... 

Also, we are pretty much "motor neutral" at EVnetics, as we have found - without getting too specific - that both motors "deliver the goods", so to speak. I will say that the WarP motors much prefer lower voltage and the Kostov's much prefer lower amperage.

However, the consequences of _briefly_ exceeding the current rating seem to be less catastrophic than exceeding the voltage rating, so that's a nod to Kostov. Conversely, it is much more likely one would exceed the current rating on a habitual basis with a Soliton1 (or a Zilla), which is a nod to NetGain.

So, like I said - they each have their advantages and disadvantages which makes it easy for us to remain motor neutral


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## Tesseract (Sep 27, 2008)

Plamenator said:


> I...
> By the way, we have a new FAQ section which you may find useful:
> http://kostov-motors.com/faq/



And I respectfully disagree with this statement: "With the currently available controllers it is very difficult to ensure the above limits are not exceeded."

I mean, it only took us 10-12 seconds to render your 144V/9" motor a smoking ruin*, which I personally wouldn't describe as "very difficult" 



* - By grossly overloading it at 5-6x its continuous power rating, so nothing to be ashamed of!


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## Plamenator (Mar 6, 2009)

"the above limits" refers to the rpm limits of 6000/7000 (11"/9") and not any amp limits (where I am sure that the Soliton and Zilla can destroy any motor in 10-20-30sec as you point out).

Here is the context of the quote (which I should have probably formulated better):

"WHAT IS THE MAXIMUM VOLTAGE THAT THE KOSTOVS CAN TOLERATE
Actually the reason we rate the motors up to 144/168/192V is not because of arcing at high voltages but because going above the stated will result in unacceptably high rpm. We have performed tests up to 220V which show that as long as rpm are below 6000 (11") and 7000 (9") the motors work fine. With the currently available controllers it is very difficult to ensure the above limits are not exceeded. Therefore we in no way encourage applying more than the rated voltage to the motor's terminals."

Indeed both the Zilla and the Soliton have tachometer inputs but these are rarely used by EVers (partly because some of the available speed sensors block the dual shaft).

Anyway, can you provide more info on:

*"Three programmable inputs*: Reverse and motor temp so far, with additional functionality to be added later"

Will it work with a KTY 84-130 thermistor? What exactly can you do with the signal?


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## Qer (May 7, 2008)

Plamenator said:


> What exactly can you do with the signal?


Well.... You REALLY expect us to specify EXACTLY what they can do, eh?


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## Tesseract (Sep 27, 2008)

Plamenator said:


> ...
> Anyway, can you provide more info on:
> 
> *"Three programmable inputs*: Reverse and motor temp so far, with additional functionality to be added later"
> ...


Reading thermistors is kind of a pain because you either need to do some heavy math (for a microcontroller, anyway) or include a "lookup table in the code ahead of time. Obviously, there are a lot of different thermistors out there so it isn't possible to accommodate all of them, but we were thinking of including lookup tables for a couple of either generic or popular ones (CPU time is precious, and so is flash memory, so it's tough to decide whether to have the microcontroller do complex math or store a lookup table).

I'm guessing this is the part number for the thermistor inside your motors, right? I know you tie one end of the thermal snap switch to an armature terminal, so it can't be used (the similar switch embedded in NetGain motors is floating). Don't see the specs for the thermistor in the technical drawing for, e.g., the 11"/192V motor. 

Anyway, the programmable inputs all go to an ADC (after appropriate filtering, clipping, etc.) so they can read analog or digital signals but they do have a rather limited bandwidth (the 3dB point is ~300Hz). Right now the only input options are to monitor the reverse lights/switch and/or the state of a thermal snap switch on or in the motor. I designed in these inputs because I know from experience you never think of everything the first go around ("640k ought to be enough for everybody!") so it's good to design in some future expansion capability.

Hmm... I just realized this is getting a bit off topic. Sorry about that.


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## Plamenator (Mar 6, 2009)

Attached is the data sheet for KTY84-130.
The Phillips' KTY range is more or less standard for golf and forklift applications and is supported by many controller producers (including for AC systems) like Kelly, Curtis, etc.
The thermal snap switch we use can easilly be detached from the armature and used. I will make a note of that and supply it with 2 free floating wires in future.
A thermistor is better though and offers real time temp monitoring.
I just tought it will be really nice if there is an easy way to have rpm and temp readings on the car dashboard. This will make a nice accessory for any controller.
Having these will also allow some fancy controller functions and make hobby conversions safer and more user friendly.


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## Qer (May 7, 2008)

Just to add some more off topic while we're playing full disclosure (  ) on the subject, it's possible to handle the temp sensor problem without wasting either precious (my preciouuuzzz) CPU time or waste flash space. The table can be generated on the fly and stored either in RAM or EEPROM and, well, I've had that as some kind of cool thing to fix at a later date.

The only thing lacking is time. My time. Now, if I tell you my paypal-account you can pay me lots of money so I can quit my daytime job and make the coolest controller software ever seen. Doesn't that sound perfect!? It does to me at least.


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## Plamenator (Mar 6, 2009)

This is really up to you to decide.
I can help you by noting that some Curtis AC controllers support up to 5 thermistor types with 3 out of 5 being from the Phillips' KTY range.
The sensor that is tied up to the armature is actually a thermal cut-off, not a thermistor, and is included as standard. The KTY84-130 is an extra on top of the cut-off 



Tesseract said:


> Reading thermistors is kind of a pain because you either need to do some heavy math (for a microcontroller, anyway) or include a "lookup table in the code ahead of time. Obviously, there are a lot of different thermistors out there so it isn't possible to accommodate all of them, but we were thinking of including lookup tables for a couple of either generic or popular ones (CPU time is precious, and so is flash memory, so it's tough to decide whether to have the microcontroller do complex math or store a lookup table).
> 
> I'm guessing this is the part number for the thermistor inside your motors, right? I know you tie one end of the thermal snap switch to an armature terminal, so it can't be used (the similar switch embedded in NetGain motors is floating). Don't see the specs for the thermistor in the technical drawing for, e.g., the 11"/192V motor.
> 
> ...


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## Plamenator (Mar 6, 2009)

http://kostov-motors.com/files/productattachments/64518679c80c77a2cde788dbab802c16_F08A7.pdf
http://kostov-motors.com/news/
http://kostov-motors.com/faq/

These are links to our new 11" 250V motor.
I would love to hear your comments/suggestions about it 
Series/parallel shifting is explained at the bottom of the FAQ.


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## DavidDymaxion (Dec 1, 2008)

Way awesome, thanks for posting. Is the series/parallel switchable field also available for the sepex motor?

Is it correct that motors, like my old Kostov, are wired with the fields in series and the armature in series?


Plamenator said:


> http://kostov-motors.com/files/productattachments/64518679c80c77a2cde788dbab802c16_F08A7.pdf
> http://kostov-motors.com/news/
> http://kostov-motors.com/faq/
> 
> ...


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## Qer (May 7, 2008)

Plamenator said:


> These are links to our new 11" 250V motor.
> I would love to hear your comments/suggestions about it
> Series/parallel shifting is explained at the bottom of the FAQ.


Cool. A compact siamese. I think you just manifested my wet dream I didn't know I had. 

Now, 250 Amps max won't, of course, make many EV'ers happy, but since that's a 60 min rating you can of course exceed it, question is how much and how long. What I'd LOVE to have is a temp-current graph that I can use to "teach" the controller how much it has to derate the current as temperature raise to avoid blowing up the motors.

Admittedly, I've never seen a graph like that for any DC-motor and as long as we're talking trucks, golf carts or EV's with shoe box controllers that's of course not much of a problem, but as batteries and controllers has gotten rather powerful my guess we'll start to see some serious motor abuse in the future. Thus it'd be nice to know how far you dare to go before the motor melts (and believe me, a motor like that in a car I drive will soon know the full impact of a Soliton...  ).

One of those with a connection for forced cooling rather than open to the environment would be perfect! I live by a gravel road so my guess is that an open motor would soon take some damage from dust.


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## paker (Jun 20, 2008)

Plamenator said:


> http://kostov-motors.com/files/productattachments/64518679c80c77a2cde788dbab802c16_F08A7.pdf
> http://kostov-motors.com/news/
> http://kostov-motors.com/faq/
> 
> ...


You've certainly got my attention, as does an 11" EV motor that weighs almost half my intended glider's ICE does.


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## david85 (Nov 12, 2007)

Is Kostov making a come back?


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## Bowser330 (Jun 15, 2008)

david85 said:


> Is Kostov making a come back?


Huge comeback! I am a happy man...Higher voltage is key to performance, just look at all the top tier EV dragsters...

I think your idea of a temp-to-amp graph would be a great idea...I am also interested in knowing what the max amps I can pull from a motor-controller combination at max rpm...

The whitezombie with one kostov 11" pulled 620A (motorA) @ 6000rpm @ 250V(sagged LA pack)

Was the 620A limited by...
(1) Motor?
(2) Controler Zilla 1K
(3) Voltage? 250V sagged?

Compare the above setup to a setup with lithiums and less overall voltage sag, to say...approx. 300V....is it possible to then pull more than 620A @ 6000rpm?


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## Plamenator (Mar 6, 2009)

Bowser330 said:


> Huge comeback! I am a happy man...Higher voltage is key to performance, just look at all the top tier EV dragsters...
> 
> I think your idea of a temp-to-amp graph would be a great idea...I am also interested in knowing what the max amps I can pull from a motor-controller combination at max rpm...
> 
> ...


The tests show that at 240-250V commutation is quite good.
Hence the limit is not voltage itself but rpm. The motor should be OK at 288-300V (even 336?).
We will soon test the high voltage version of the Kostov 13" which is expected to go to 288-336V at 300-330A. This should make you even happier 
Though do not take it as a promise - it is all subject to successfull tests.

The limit for the White Zombi was the motor. 620A is too much for a prolonged period (620A generate 9 times more heat than 210A). Because of the much higher resistance of the stator (vs that of the armature) the problem with amp overload is in the stator windings. 
I cannot recall the time it took the WhiteZombi's Kostov to blow at 620A though...

The temp-amp graph is not usually provide due to:
-too much information for the competition 
-too difficult to compile (a lot of tests needed)
-different amps call for different rpm which results in effectiveness of ventilation hence data is not directly comparable.
Anyway, do you mean something like amps on X axis, temp on Y axis and all that for at least S2-60? Meaning that top amp will be 250? Problem then is that at 150A rpm will shoot through the roof hence test should be at 144V in parallel mode. Are you thinking along the same lines?


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## Plamenator (Mar 6, 2009)

Qer said:


> One of those with a connection for forced cooling rather than open to the environment would be perfect! I live by a gravel road so my guess is that an open motor would soon take some damage from dust.


This is also in the plans - air turbine (grand name for something that is quite small) is purchased and should be attached to motor within a month - will keep you posted.
I hope that it will increase 60min amps somewhat. The motor for the turbine will be 50-100W at 12 or 24V. If you find a way for the controller to controll that small motor too, you can increase ventilation rather than degrade main motor amps


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## Plamenator (Mar 6, 2009)

DavidDymaxion said:


> Way awesome, thanks for posting. Is the series/parallel switchable field also available for the sepex motor?
> 
> Is it correct that motors, like my old Kostov, are wired with the fields in series and the armature in series?


Yes, it is even easier to be done in SepEx but it is kind of pointless.
You can achieve the same effect by reducing the voltage of the sepex windings (less amps pass through stator, weaker field - higher rpm).

You are right about your old Kostov. The windings of the 11" 250V are completely different though - it just happens that at 144-192V performance is identical but it is achieved by different constructions.
What you can do is modify it yourself (can give you instructions if you wish) to have the switching. Than you can switch to parallel which will give you higher rpm and in effect make the motor usable at 96-120V.


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## Qer (May 7, 2008)

Plamenator said:


> -too much information for the competition


You can send it in private to me, I promise I'll be quiet. Trust me! 



Plamenator said:


> Anyway, do you mean something like amps on X axis, temp on Y axis and all that for at least S2-60? Meaning that top amp will be 250?


Well, I don't know what Bowser wants, but I'd preferably want a temp-current-graph that shows max current right now. Ie, if the motor is 50C it's ok for the controller to feed 800 Amps (just pulling numbers out of a hat here, no relevance to any existing motor) but as the temperature reaches 75C the current has to be decreased to 700A and so on. No predicting for how many minutes or so, just a simple graph for the controller to know how much it should limit current so nothing starts to melt so it can adjust continuously.

That'd also take away the rpm-problem, at least I think so. It doesn't matter if the motor is running at 500 or 5500 RPM, as temperature rises current will go down. If you run at low RPM, current will drop faster.

And I can fully understand if you don't want to reveal all information you have about the motor, but on the other hand I think it might be better to reveal at least this information to avoid blown motors and unhappy customers in the future...


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## Bowser330 (Jun 15, 2008)

Qer said:


> ....Well, I don't know what Bowser wants...


I want what you want man! 

About the RPM graph, I just was wondering if we could get graphs that more closely ressemble the ICE engine graphs...

so RPM on the x-axis and Torque/amps on the y-axis...

but more specifically, the amps would be the maximum rated amps that could be applied to the motor at that speed...

maybe im not making any sense, Im not an electrical guy, but I just feel that graphs that compared closer to ICE graphs would probably appeal more to the average DIYer...I know for a fact there are tons of smart people on this forum that can work with the other graphs but..i feel i would benefit better with a standard style...

example....Keep battery technology constant (hopefully lithium since thats the direction people are going in)

and have 1 graph that could show the....
kostov 11" @ 144V 192V 250V 300V 
or 
warp 11" @ 144V 156V 192V

so that the graph could show how the max speed for pulling say 1000A goes up as you increase the voltage....with those graphs a DIYer could probably gear their EV more appropriately...


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