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Old 11-10-2010, 07:27 PM   #17 (permalink)
TomEV
Ford Escort 2.0
 
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Join Date: Feb 2008
Location: Alameda, CA
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Electricar - '89 Ford Escort LX Hatchback
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Quote:
Originally Posted by robchalmers View Post
Have you tried retarding the timing? earlier contact earlier push/pull. I also found it would keep the temps lower.
Problem with retarding the brushes is that it reduces the top end speed. Without field weakening, at zero degrees my top speed was 32 MPH. At five degrees advance, top speed is 34 MPH. At ten degrees, it goes back to 32 MPH, accelerates slower and is much less efficient. I'd imagine that at -5, it might be more efficient, and perhaps a bit more acceleration, but the top speed would be around 30 MPH.

For this motor at 48 volts, (rated for 36 volts, 98 amps) five degrees advance is a good number. It will probably need a bit more advance when I increase the pack voltage next year.
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