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Old 11-28-2018, 01:13 PM   #17 (permalink)
Karmann Eclectric
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Join Date: Feb 2010
Location: Graham, WA
Posts: 165

Odysseus - '00 Honda Odyssey

MR BEAN - '12 Mitsubishi i-MiEV SE

Karmann Eclectric - '71 VW Karmann Ghia Electric Conversion

BOB - '87 Ford 250 Lariat ext cab
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conversion motors and GM's EV subsidies

More context is a good thing on Trump's bluster, as GM is only 10,000 cars away from their 200,000 vehicle cap on EV tax credits anyway. The credit will go from $7500 to $3750 for the 2nd quarter after hitting that target, then down to $1875 for another 3 months before hitting zero. There are efforts afoot to extend that credit, which is the main thing he could affect.

Now back to motors for conversions. Analogous to rotor tip speed with helicopters, the speed of the commutator under the brushes is a limiting factor on series wound brushed motors, which is proportional to the motor diameter. So a larger motor will have more starting torque, but a lower top RPM. Since starting torque is rarely an issue in EV conversions but highway passing power is, a smaller motor, or especially multiple small motors can be the best solution, as they can reach higher RPMs. Efficiency will not change appreciably between say a 6" and a 9" series motor.

My 9" series motor has externally wired fields that can be switched from series to parallel. This provides maximum starting torque in series, and then further down the dragstrip, switching to parallel provides more power at high RPMs.
2012 Mitsubishi i-MiEV, 112 MPGe
2000 Honda Odyssey
1987 F250 Diesel, 6.9L IDI, goes on anything greasy
1983 Grumman Kurbwatt, 170 kW "Gone Postal" twin
1983 Mazda RX-7 electric, 48 kW car show cruiser
1971 VW Karmann Ghia electric, 300 kW tire-smoker
1965 VW Karmann Ghia cabriolet, 1600cc
Have driven over 100,000 all-electric miles!
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