# Looking for Feedback on Kostov motors



## Kelmark (Oct 26, 2009)

Does anyone have experience with or heard about the (Kostov 11" 250V)? 

I was looking for something between Netgains warp 9 and Warp 11HV in size and power. 

This motor has interpoles so I would still get the advantage of longer torque band. And on their website they have made some recent improvements to their motors.

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


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## esoneson (Sep 1, 2008)

subscribe...me too!


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## Kelmark (Oct 26, 2009)

I know Plazmaboy's White Zombie blew one up while pushing the upper limits of the motor RPM. Then they switched to the dual netgain motors.


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## DavidDymaxion (Dec 1, 2008)

I have an old Kostov. Mine has much smaller brushes than the Warp 11. I've heard and believe the Kostovs handle higher voltages better, but less current than the Warp motors. Kostov says the interpoles make the brushes' life easier, so they don't need to be as big.

My Kostov is about 180 lbs, I think the Warp 11 is about 250 lbs. The Warp is also slightly bigger in diameter and length.

I haven't really torture tested my motor, the car still needs more work, but I'll report when I do. So far it has putt-putted around great on 48V.


Kelmark said:


> Does anyone have experience with or heard about the (Kostov 11" 250V)?
> 
> I was looking for something between Netgains warp 9 and Warp 11HV in size and power.
> 
> ...


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## azdeltawye (Dec 30, 2008)

Kelmark said:


> Does anyone have experience with or heard about the (Kostov 11" 250V)?
> ......


 
I posted some pics and info on the 168V 11" awhile back:

http://www.diyelectriccar.com/forums/showthread.php/kostov-11-inch-dc-motor-construction-34775.html


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## Kelmark (Oct 26, 2009)

azdeltawye said:


> I posted some pics and info on the 168V 11" awhile back:
> 
> http://www.diyelectriccar.com/forums/showthread.php/kostov-11-inch-dc-motor-construction-34775.html


Have you made any progress with your build and what controller did you decide on?


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## Guest (Jul 25, 2010)

I have two of the older style Kostov 11" motors. They will do OK at 156 but I would not go more than that. They are lower rpm motors than the new HV Kostov motors. The new Kostov HV motors use a much larger com and brushes. I am going to be using a Rebirthauto adaptor plate for one of mine. I have one for a spare and I even have a spare set of field windings and armature. I will be putting it into my Buggy. I will be using 96 volts and the Kostov in the buggy. I hope the torque will be good and I hope it will be better than my 9" motor. I'd love to get my hands on a Kostov HV 11" motor. The HV Kostov is also longer like the warp. Cheaper too. Uses the same bolt pattern and shaft size. So if you have a Warp 9 and want to upgrade you can up grade to the HV Kostov 11" and still use your adaptor plate. It was good of them to do that. 

Pete


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## DavidDymaxion (Dec 1, 2008)

Just curious about the 156 Volt number: Is that personal experience or where did you get that? Thanks.

Here is an old post by Rich Rudman about his Kostov:



> Ok here's the way I take the Kostov 11 incher. I have one in the Fiero.
> With the Raptor in it the Comm "sings"
> at about 800 motor amps, and about 5000 rpm. I take this to be insipent
> arcs. READ NOT good but not leathal.
> ...





gottdi said:


> I have two of the older style Kostov 11" motors. They will do OK at 156 but I would not go more than that. They are lower rpm motors than the new HV Kostov motors. The new Kostov HV motors use a much larger com and brushes. I am going to be using a Rebirthauto adaptor plate for one of mine. I have one for a spare and I even have a spare set of field windings and armature. I will be putting it into my Buggy. I will be using 96 volts and the Kostov in the buggy. I hope the torque will be good and I hope it will be better than my 9" motor. I'd love to get my hands on a Kostov HV 11" motor. The HV Kostov is also longer like the warp. Cheaper too. Uses the same bolt pattern and shaft size. So if you have a Warp 9 and want to upgrade you can up grade to the HV Kostov 11" and still use your adaptor plate. It was good of them to do that.
> 
> Pete


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## Guest (Jul 25, 2010)

> Just curious about the 156 Volt number:............where did you get that?/QUOTE]
> 
> Kostov
> 
> ...


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## DavidDymaxion (Dec 1, 2008)

Many thanks, I'm glad to get every data point I can.

So as I soon pass 156 V or 4000 rpm, I just tell myself it's not a party until something gets broken.







(my motor does have some race mods so I hope it's more robust than the stock motor).


gottdi said:


> > Just curious about the 156 Volt number:............where did you get that?
> 
> 
> Kostov
> ...


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## Guest (Jul 25, 2010)

What Mods?


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## DavidDymaxion (Dec 1, 2008)

Randy of Canadian EV modded it. It is supposed to have been rewound with higher temperature wire, has armature banding, better brushes, and better bearings.


gottdi said:


> What Mods?


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## Guest (Jul 25, 2010)

Can't imagine higher temp wire. The wire is fat and flat for all field windings. Maybe higher temp coating. Can't imagine much better than H rating. Which they are. 

I can see comm banding and better bearings. I know about the winding wire. Damn thick and heavy. I'd bet that that stuff could handle loads of amps.


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## DavidDymaxion (Dec 1, 2008)

My motor is a sepex, so the field windings are with fairly fine wire (unlike a series motor). I presume the fields got the better wire.


gottdi said:


> Can't imagine higher temp wire. The wire is fat and flat for all field windings. Maybe higher temp coating. Can't imagine much better than H rating. Which they are.
> 
> I can see comm banding and better bearings. I know about the winding wire. Damn thick and heavy. I'd bet that that stuff could handle loads of amps.


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## toddshotrods (Feb 10, 2009)

Kelmark said:


> I know Plazmaboy's White Zombie blew one up while pushing the upper limits of the motor RPM. Then they switched to the dual netgain motors.


Play nice, IIRC, he actually blew the motor doing the longest EV burnout in history. When he first changed from the single 11, to the twin 8s, there wasn't any significant difference in performance. He eventually developed the dual motors to provide better performance. In defense of single motors, Smoke Screen eventually surpassed his performance with a single 13" GE motor. I'm not saying either is better just throwing some facts out for consideration. I wonder what that 11", or maybe an 11" Warp, would have been capable of with the same development effort and time.


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## Guest (Jul 25, 2010)

I was unaware that yours was a sepex Kostov. I can see better field windings for higher amperage there. What kind of controller are you using with your sepex? 

Pete


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## Guest (Jul 25, 2010)

DavidDymaxion said:


> My motor is a sepex, so the field windings are with fairly fine wire (unlike a series motor). I presume the fields got the better wire.


I took a look at your web site. I looked at your run at the salt flats too. You mentioned that you were running 48 volts to the motor. Both field and armature. How are you controlling the amperage to the field? You mentioned that the motor was hot at the end of the run and it looks like you have a cooling fan on it too. I think your running way to much amperage through the field compared to to the armature. I think that is where your getting your heat. No need to over volt/amp the field. 

What controller are you using?

Pete 

Got some good photos of your comm on your motor? I'd like to see the modification. Got some good photos of your motor and controller setup?


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## toddshotrods (Feb 10, 2009)

toddshotrods said:


> Play nice, IIRC, he actually blew the motor doing the longest EV burnout in history...


Oops, he did blow the Kostov in a race. Had my facts screwed up...




toddshotrods said:


> ...When he first changed from the single 11, to the twin 8s, there wasn't any significant difference in performance. He eventually developed the dual motors to provide better performance...


I had that part right. He was in the mid-13s with the Kostov, and bounced around between tehre and 14s when he first went to the siamese s, but eventually started flying.

He did say that he would have still been developing the single 11, if it hadn't zorched.


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## Bowser330 (Jun 15, 2008)

toddshotrods said:


> Oops, he did blow the Kostov in a race. Had my facts screwed up....


No you didn't, you were right the first time...I distinctly remember a story (that has now been changed in the White Zombie History page), about doing an attempted burn-out and breaking the motor that way...hmmmm...something shady going on...

*Edit*

I found an old post where it was discussed before...way back in Dec.2008....Proof I am not crazy....

Originally Posted by *DavidDymaxion*  
_Those are some awesome numbers!

John actually didn't burn up his motor doing a burnout... He was trying to do a burnout but the wheels bit and didn't spin... But it did skid the front wheels. He estimates this went on for 30 to 40 seconds. This is the almost the worst treatment you can give a motor, it was turning very slowly whilst being fed 1200+ Amps! The only thing worse would have been locked rotor._


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## toddshotrods (Feb 10, 2009)

Bowser330 said:


> No you didn't, you were right the first time...


I thought so! Man, that was really bugging me because I was so sure I had read that before! I am also sure I saw something on Jim's site about a new siamese 9" for the Zombie, with a reference to his old siamese 8s, that doesn't seem to be there anymore.

Interesting.  Thanks for helping me preserve the tiny bit of sanity I have!


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## Kelmark (Oct 26, 2009)

Thanks for all the great feedback. I gather the motor would hold up well to running 1000A controller and rpms up to 5500. 

Also appreciate the correction on how the motor was eventually burnt up. My reason for not going with dual motors 8” or 9” is loss of efficiency. Originally I wanted to go with an AC motor but living in Kansas I would not be able to maximize the benefit of regen. Also there still is not an affordable kit with the power I would be happy with.

So my next question is on the efficiency of the 11” Kostov compared to Netgains Warp 9? With all other variables being the same, I.E. vehicle, VW drive train, speed 55mph, flat road, 0 headwind, ect. 

Typically I would not be pushing 1000 amps; the car I am using is going to weigh around 1800 lbs when it is done. It’s just nice to have the power available and not push components at their upper limits. Also it is my understanding that the more amps you pull the less efficient the motor becomes.


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## Bowser330 (Jun 15, 2008)

Kelmark said:


> Thanks for all the great feedback. I gather the motor would hold up well to running 1000A controller and rpms up to 5500.
> 
> Also appreciate the correction on how the motor was eventually burnt up. My reason for not going with dual motors 8” or 9” is loss of efficiency. Originally I wanted to go with an AC motor but living in Kansas I would not be able to maximize the benefit of regen. Also there still is not an affordable kit with the power I would be happy with.
> 
> ...


I am not too sure about holding 1000A @ 5500rpm, but holding either,seperately, yes, happens all the time...

There is an on going debate about which is more efficient single vs dual/siamese, I personally feel the difference wouldnt be very noticable, The white zombie (siamese) gets great range with its new lithium pack...projecting about 120miles....and from a 26kwh pack, = 217wh/mile....pretty damn good efficiency if you ask me...

Efficiency curves can be found on Kostov-motors power graphs on their website, typically in the 80+% range for peak eff%...

1000A through an 11" is close to 300ftlbs of torque, in a 1800lb. vehicle that will twist and launch pretty hard...make sure you have the motor sufficiently mounted and anchored within the chassis...have fun!


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## Kelmark (Oct 26, 2009)

Bowser330 said:


> I am not too sure about holding 1000A @ 5500rpm, but holding either,seperately, yes, happens all the time...


Sorry, that is what I was I meant. Highest amps at take off tapering off at higher RPM and setting the redline at 5500 RPM. 



Bowser330 said:


> There is an on going debate about which is more efficient single vs dual/siamese, I personally feel the difference wouldnt be very noticable, The white zombie (siamese) gets great range with its new lithium pack...projecting about 120miles....and from a 26kwh pack, = 217wh/mile....pretty damn good efficiency if you ask me...


217wh/mile is really good I am trying to stay below 200wh/mile at 50mph. Looking at using a similar sized lithium pack for my car. So do you think the single 11" Kostov would do better or worse than dual motors? My thinking might be flawed in that dual motors are less efficient.



Bowser330 said:


> Efficiency curves can be found on Kostov-motors power graphs on their website, typically in the 80+% range for peak eff%...


Was hoping for a better real world comparison. 



Bowser330 said:


> 1000A through an 11" is close to 300ftlbs of torque, in a 1800lb. vehicle that will twist and launch pretty hard...make sure you have the motor sufficiently mounted and anchored within the chassis...have fun!


I know, a bit much for a kit car but I can start at 600A and tweak it up to what feels right for the car.


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## DavidDymaxion (Dec 1, 2008)

I'll post up some pics -- it's hard to see through the brush holes, so hopefully they'll be illustrative.

I agree 48V is high for the field and the cause for my heat. The motor gets quite hot in about 10 minutes at that level, even if armature current is low. Regen makes it even worse, as you can get as high as around 60 Volts during regen. So 48 Volts will be a momentary kind of thing, not a steady state field voltage.

I'm doing a custom WWI era type controller. I'm trying to throw it together now. Basically it's a rheostat on the field and voltage switching for the armature. More details are forthcoming on that.

The Salt Flats run was done with just the stock internal fan, and the motor was run at about 1/3 max rpm -- which means less cooling air. This year I'll be running higher rpm, plus putting on an extra cooing fan that can blow full force even when the motor is off.


gottdi said:


> I took a look at your web site. I looked at your run at the salt flats too. You mentioned that you were running 48 volts to the motor. Both field and armature. How are you controlling the amperage to the field? You mentioned that the motor was hot at the end of the run and it looks like you have a cooling fan on it too. I think your running way to much amperage through the field compared to to the armature. I think that is where your getting your heat. No need to over volt/amp the field.
> 
> What controller are you using?
> 
> ...


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## Bowser330 (Jun 15, 2008)

Kelmark said:


> Sorry, that is what I was I meant. Highest amps at take off tapering off at higher RPM and setting the redline at 5500 RPM.
> 
> 217wh/mile is really good I am trying to stay below 200wh/mile at 50mph. Looking at using a similar sized lithium pack for my car. So do you think the single 11" Kostov would do better or worse than dual motors? My thinking might be flawed in that dual motors are less efficient.
> 
> ...


what type of kitcar if you dont mind me asking?


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## Kelmark (Oct 26, 2009)

Bowser330 said:


> what type of kitcar if you dont mind me asking?


1978 Kelmark GT (Fiberglass Replica of a Ferrari Dino)


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## Guest (Jul 27, 2010)

Got some photos of your Kelmark GT? Love those things.


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## Kelmark (Oct 26, 2009)

gottdi said:


> Got some photos of your Kelmark GT? Love those things.


I started a build thread a while back, project is on the back burner this summer but will be back on it this fall.

http://www.diyelectriccar.com/forums/showthread.php/kelmark-gt-solar-series-hybrid-41024.html


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## Guest (Jul 27, 2010)

I remember.


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## algea07 (Oct 1, 2010)

i read on the Soliton manual that kostov motors were neutrally timed, where the warps are advanced timed, which meant that the kostov couldn't take as much amperage.

i was planning a dual nine conversion can a nine inch kostov take 1000amps and what about 1400amps.

i'd like to be able to max out the soliton if i can, if i my car can handle it. drag racing isn't my primary concern but i'd like to go fast if i need to.


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## piotrsko (Dec 9, 2007)

algea07 said:


> i read on the Soliton manual that kostov motors were neutrally timed, where the warps are advanced timed, which meant that the kostov couldn't take as much amperage.
> 
> 
> algea07 said:
> ...


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## DavidDymaxion (Dec 1, 2008)

The Kostov has interpoles. These are electromagnets between the main poles that help keep the fields aligned under high current and high rpm. The other way to do this is to advance the timing to the rotated state. The interpoles do alignment dynamically, so in theory are better at it. The flip side is the interpoles take up room, so the main field poles are smaller.

My old Kostov 11 inch is lighter than a Warp 11 (about 70 lbs lighter), the commutator is smaller, the brushes are smaller, and the brush leads are smaller. I would believe these are the bottlenecks for high currents, not the timing. BTW Kostov says the interpoles help the brushes lead an easier life, so they can handle more current.


algea07 said:


> i read on the Soliton manual that kostov motors were neutrally timed, where the warps are advanced timed, which meant that the kostov couldn't take as much amperage.
> 
> i was planning a dual nine conversion can a nine inch kostov take 1000amps and what about 1400amps.
> 
> i'd like to be able to max out the soliton if i can, if i my car can handle it. drag racing isn't my primary concern but i'd like to go fast if i need to.


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## Anman (Feb 5, 2010)

So not a lot of builds use kostov motor's although they seem nice. Is there something I am mssing?


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## Jozzer (Mar 29, 2009)

I've got an 11" 250v in my MX-5, it's absolutely fantastic. I've only done a few hundred miles so far, so cannot yet comment on it's durability, but it seems to be taking it well so far. I've abused it as often as possible with up to 1000A @ 220v, and will be pushing upwards to 300v shortly when time permits.
The power of this combination motor/controller is nothing short of breathtaking..

I can manage 200wh/m round town if I try REAL hard, 250 with short spells of 50mph "freeway" mixed in.
400+ wh/m happens easily when your naughty.

Vehicle weight < 1100KG.


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## DavidDymaxion (Dec 1, 2008)

That seems to be right. There were several notable failures (John Wayland tortured his to death), and others had some problems under heavy use. Recently I melted some brush gear on mine, but that's racing. These were all with the older motors. My understanding is the newer ones are better.

The Kostovs seem to like more voltage and less current, which is the opposite of most DC conversions that tend to go for less voltage but more current.


Anman said:


> So not a lot of builds use kostov motor's although they seem nice. Is there something I am mssing?


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