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Old 09-22-2010, 09:30 PM   #35 (permalink)
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I have never had a bike with pwm only shunted current, touching one convinced me that newer designs were not available. Thanks for the info. A google search brought me up to date.

Still I don't buy the economics of a new vehicle.

Quote:
Originally Posted by dcb View Post
(Motorcycle) PM generators are efficient,
1. no field charge, ever
2. no fan needed
3. excess current is not "shunted to ground", that would only make the engine do extra work.

Newer units *should* be utilizing switching(pwm) to ensure only enough energy is tapped from the alternator to maintain battery voltage. Older units probably used linear regulation which makes more heat, which may be the source of the confusion. If the regulator designers are really geeky they would add synchronous rectification, which has far less loss than plain old bridge rectification. But we are not talking about a huge amount of current on your typical motorcycle and it adds significantly to the cost vs a simple pwm scheme and a handful of diodes.
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