# ME0709 Performance



## xrotaryguy (Jul 26, 2007)

Hello, 

I am working on an electric formula car project with a group of other students. We are using an ME0709, but wondering if this will give us the performance we want. The specs on Electric Motorsports' web site say we can make about 11.4 hp at 72 V and ~135 A. At 500 lbs (car and driver), the car would have a considerably poorer power to weight ratio than an 81 Rx7, a fairly slow car by today's standards. 

So my question is this, has anyone run higher voltage or higher amperage through this motor? If so, how did the motor perform? Cooling system?

Thanks,


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## major (Apr 4, 2008)

xrotaryguy said:


> Hello,
> 
> I am working on an electric formula car project with a group of other students. We are using an ME0709, but wondering if this will give us the performance we want. The specs on Electric Motorsports' web site say we can make about 11.4 hp at 72 V and ~135 A. At 500 lbs (car and driver), the car would have a considerably poorer power to weight ratio than an 81 Rx7, a fairly slow car by today's standards.
> 
> So my question is this, has anyone run higher voltage or higher amperage through this motor? If so, how did the motor perform? Cooling system?


Hi xrot,

Your motor is a commutator PM DC motor. It will be limited thermally and also by commutation. While you might be able to increase power by increasing voltage and/or current, you will find it sensitive, to say the least. This means likely failure. Increasing cooling with air blast will help a little thermally, but not with arcing. In eMC racing, brushed PM motors have not held up well. 

Your best bet is to go to AC, either ACIM (induction) or BLDC (AC PM). Barring that, I suggest a wound field DC. They are more robust than the PM and will tolerated overload (more power) much better.

Regards,

major


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## xrotaryguy (Jul 26, 2007)

Certainly I'm concerned with the durability of the brushes and commutator. I have also have magnets come loose on PM motors, brushed or otherwise. Some motors are more resilient than others. 

One of the things I want from a motor is regen. All of the "AC" solutions you proposed would work. I am also considering sepex motors. 

Thanks for the input.


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