# Building cheap 8KW Motor for EV



## ashkar_malik (Mar 18, 2012)

Any Help to build a ~6KW AC motor for Ev is welcome
Specs-
Voltage-92v
Current-60A
RPM-Above 3,000
Efficiency-More than 86% [Preferred >90%]


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## madderscience (Jun 28, 2008)

It would be helpful to define what 'cheap' is (what you actually want to spend) and also the type of motor, for example series wound, shunt, permanent magnet, brushless DC, AC, etc.

However, motors with this kind of specs are generally considered pretty small in the EV world, and thus can be found used for a few hundred dollars down to free, depending on where you are and what sort of industries are around. Many brushed DC electric forklift motors or golf cart motors, for example, will have specifications in the ballpark you are hoping for. For that matter, the controller, charger, fuses, and many other components from that same forklift or golf cart might be usable in a low power EV. Just pick the highest voltage one you can find. This kind of equipment usually runs 36 to 72 volts. The motors, if series wound, will likely work fine in a higher voltage system because the controller will be stepping down the voltage anyway, and brushes can be advanced if needed to prevent arcing. You can't overvolt motor controllers and chargers so if you find a 48v golf cart you will only be able to use the motor and maybe wiring and fuses, you would need to find a 72b or 96v charger and controller. 

Building a motor from scratch, if that is indeed what you are implying, is going to be a lot of work and you will likely end up with a less reliable, less efficient end product.


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## ashkar_malik (Mar 18, 2012)

madderscience said:


> It would be helpful to define what 'cheap' is (what you actually want to spend) and also the type of motor, for example series wound, shunt, permanent magnet, brushless DC, AC, etc.
> 
> However, motors with this kind of specs are generally considered pretty small in the EV world, and thus can be found used for a few hundred dollars down to free, depending on where you are and what sort of industries are around. Many brushed DC electric forklift motors or golf cart motors, for example, will have specifications in the ballpark you are hoping for. For that matter, the controller, charger, fuses, and many other components from that same forklift or golf cart might be usable in a low power EV. Just pick the highest voltage one you can find. This kind of equipment usually runs 36 to 72 volts. The motors, if series wound, will likely work fine in a higher voltage system because the controller will be stepping down the voltage anyway, and brushes can be advanced if needed to prevent arcing. You can't overvolt motor controllers and chargers so if you find a 48v golf cart you will only be able to use the motor and maybe wiring and fuses, you would need to find a 72b or 96v charger and controller.
> 
> Building a motor from scratch, if that is indeed what you are implying, is going to be a lot of work and you will likely end up with a less reliable, less efficient end product.


I totally Agree with you ,Building a Motor from scratch is really very hard but I hope that it would be worth designing a new one.As to keep the cost down to minimum.On an average budget of about $300,I am Planing to build a PMAC /BLDC or a Pancake Motor or maybe a Coreless Motor,Because my main Preference is Efficiency ,Torque and Cost.
Weight is also crucial for my application.
Any type of help is welcome.


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