|
|
Posted by David Sherman [72.47.9.228] on Tuesday, January 25, 2011 at 22:05:24 :
In Reply to: Overspinning a Generator? posted by Will (in IL) [98.215.26.138] on Tuesday, January 25, 2011 at 21:37:54 :
I don't know what the max safe RPM for a generator is, except that it's less than for an alternator. Supposedly the commutator flies apart first if you overspeed it.
The overcharging issue is separate, though. The regulator should cut the amps back to near zero when the battery is fully charged, no matter how fast the generator is spinning. Check the field voltage. It should be near zero with the battery charged. If not, the regulator "thinks" the battery needs more charging. Check the voltage from the battery terminal of the regulator to the case of the regulator. If it's significantly less than the actual voltage at the battery posts, you probably have a good regulator that's being fooled by a bad connection somewhere, possibly even between the regulator case and the chassis. Put a digital voltmeter across each connection and cable and look for an an unexpectedly large voltage drop. Other guys just take every last connection apart and sand it shiny, but I'd rather find the actual problem first. If the voltage between the B terminal of the regulator and its case is too high (say more than 14.5 volts) and the regulator is putting out field current, then the regulator is out of adjustment. If it's mechanical, bend the spring tang on the voltage coil very slightly so as to reduce the tension on the spring. I've also seen regulators whose points were welded together due to some abuse of the electrical system. That will definitely cause continuous over-charging, so first make sure the points move freely. In normal operation, with a charged battery, they should vibrate slightly, with a tiny spark that's visible in a dark room. You can figure a lot out just by manually opening and closing each coil's points and seeing what happens.
Follow Ups: