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Old 11-23-2015, 12:30 AM   #2346 (permalink)
P-hack
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well I know you have an idea for a solution in search of a problem, but lets focus on what you have to work with then.

the mgr is listed as 50kw, but you mentioned 75kw, assuming you get there with more current and not just revs, then at 360v you should be able to approach 41kw, which is only 114 amps per motor, or 456 amps, a comfortable margin below 600 amps.

Your units also have gearing fixed, which is a problem from a top speed perspective probably, but with all 4 units you should be able to exceed 3000 lbs of force, might even approach 1g off the line if the car is light enough (does your car weigh less than 3000 lbs?), but I don't know how you figured 75kw.

If you go with stock 50kw mgr figures the breakdown speed can be interpolated from the lower voltage (360v leaf pack assumed, might have to charge it fully to account for voltage drop)

50kw * 360 / 650=27kw. 610 wheel rpm * 360 / 650= 337 rpm where the torque falls off. I dont know your wheel size, but if they are 2 feet rolling diameter, that is 24mph. And 75 amp per motor, 300 from the battery.

Even with 650 volts, it will peak before 44mph.

But taking the simple case, 360v, does field weakening in a pmac take extra current? I.e. you have to "cancel out" the existing rotor field somehow to increase the rpm? Or are you able to somehow shift to a more reluctance based torque angle when the bemf rises?

Also, 650/360 is 1.8. The voltage change from wye/delta is 1.732, you should *really* make sure there isn't a trivial way to change it over to delta, because it would be nearly a perfect fit for the leaf battery then. you would be at 50kw * 4 @520 battery amps max (@375v).

Last edited by P-hack; 11-23-2015 at 12:42 AM..
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