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Old 09-03-2012, 09:12 AM   #42 (permalink)
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Originally Posted by Daox View Post
Where are you going to get this 36V from? A dc/dc converter?

I think 36V is still much too low. If your motor is rated for 1.5hp continuous at 95V, you have roughly 1/3rd that hp available at 36V, so only .5hp. I'd guess you need around 1hp at least to run the A/C. Therefore, I'd run it at at least ~63V (95*.66), and get a pulley to make your rpms at the compressor to what they would have been at idle or slightly above with the OEM engine. You can fairly accurately estimate the rpms by looking at the stock volts per rpm specs. At 95V you get 6750 rpm, or 71rpm/V. So, at 63V you would get 4475 rpm. I did these same calculations when I put the PM motor in my riding lawn tractor and it worked out great.
It's about the RPMs of the motor and what these little guys can really handle before the brushes spark. I tried 48v and 36 volts with the 3" pulley and 36 volts ran much nicer on the pulley and the A/C compressor was operating, blowing cold air into the hot car.

I am building a small 50 AMP motor controller that will take pack voltage (144v), I'll be making the compact PCB this week.
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