# Kostov DC Motor - What do I really have?



## major (Apr 4, 2008)

iggymo said:


> If I read the specs of their other motors on their site correctly, these numbers corrospond to 5.2 Kw, 220volt and %28 Duty Cycle.....Is this right? (Steve K.)


Hey Steve,

220 volts? Don't think so. Maybe 220 amps.

major


----------



## iggymo (Apr 17, 2009)

Hi Major,

I was unsure too. I was looking at the website www.kostov-motors.com and all of their motor data shows the numbers as "Kw/Voltage/Duty Cycle". The only one I could find that had a 22 in the middle set of numbers was shown as a 220 volt DC motor. Other motor are shown as 2.4 for 24 volts, 4.8 for 48 volts, 7.2 for 72 volts etc.

http://kostov-motors.com/tractionmotors/dcsepexmotors/framesize191mm/

So.... That's kinda why i think it might be 220 volts DC. Now, They may have used the same end plate for different motors and never changed the data stamped into it, or it may be a one-off wrong assembly. Who knows.
If it was a 5.2Kw 220 VDC Series motor (Let's just pretend) What would it do if I ran it at 48-72 Volts? What would the speed be like and how would that affect how many amps I could dump into it?

-Steve K


----------



## major (Apr 4, 2008)

iggymo said:


> Hi Major,
> 
> If it was a 5.2Kw 220 VDC Series motor (Let's just pretend) What would it do if I ran it at 48-72 Volts? What would the speed be like and how would that affect how many amps I could dump into it?
> 
> -Steve K


5200W / 220V = 24A. 24A * 72V = 1728W. So 1.7kW.

RPM would be in proportion to the motor voltage. So 72/220 or 33% of design speed.

It would suck big time. Going lower in voltage generally does not change current handling capability. If it was a 220 volt motor, it'd be a 24 amp motor.

Not likely at all.

major


----------



## iggymo (Apr 17, 2009)

Hi Major,

Thanks for the refresher in Ohm's Law....sometimes I forget what I learned a long time ago. I think I will try my luck and see what it does in the car. I am modifying the shaft so I should be able to mount it to a standard mounting plate and use a coupler that can be used on a different motor if needed. Hopefully it will work, but if not, I will just have to do a different motor and stay with the same controller and power system.

The pessimist in me says it's another thing to go wrong, but then I think of how much I am learning about all this and that has a lot of value to me. If anything I will learn a few different ways NOT to make an electric car (Thanks Mr. Edison!).

Major, Thanks for answering all my questions, I appreciate your time and enthusiasm for all this. Maybe someday I can help someone starting out too.

-Steve


----------



## Plamenator (Mar 6, 2009)

Hi,
The motor you have is really not good for EV conversions.
It is originally meant for the pump of a forklift.
Its parameters are:
-5.2kW
-22V (not 220V)
-2800rpm
-S4-25% (~S2-15min?)
-compound excitation
-295A
Can send you an official drawing if you drop me a note at [email protected]. The motor is discontinued by the way


----------



## iggymo (Apr 17, 2009)

Hi!

Thank you for the info, you just saved me about $300 getting the shaft of the motor modified for the EV I am planning! I guess I am once again searching for a DC motor for the car...
I would not have thought it was a 22 volt motor, never realised anything ran at that low of a DC voltage.
Maybe I could use this in a motorcycle EV down the road? Pretty big for a motorcycle. Maybe Ebay?

Thanks again!
-Steve (Iggymo)


----------



## Plamenator (Mar 6, 2009)

well, if you can live with the compound excitation, you can use it at 150-200A nominal which will both increase your rpm to the preferable 3500-4000ish range and increase duty to 30-40-45min which is now sort of acceptable for a motorbike despite the reduced power.
as far as I now, Sevcon makes some compound controllers.


----------

