> So, What is really the maximum continuous current rating for our
> generators? I would assume that 22 amps is the limit based on what I saw
> in the specifications page of the Haynes manual. But my present regulator
> is allowing more than that! I am going to order one of these electronic
> regulators and I want to specify the highest safe current limit. So, what
> should I tell him?
I honestly don't know the answer to that, Tony. Personally, I'd be leery of
exceeding the 22 amp (19 for earlier units on TR2/3) rating for very long;
since I know from personal experience that it's not hard to burn up a TR
generator in 30 or 40 minutes of continued high-speed overcurrent operation.
I believe the original circuit worked as well as it did because the old
batteries' charge voltage would rise fairly quickly to at least 13v or so, in
less time than it took for the generator to overheat and start throwing solder.
And sometimes, of course, it simply let the generator burn up. I've never
understood the decision to use the 2-coil regulator on the TRs, especially
since a 3-coil unit was used on Spitfire (and Vitesse).
Unless you're willing to test several units to destruction, my suggestion would
be to give him the factory rating and consider yourself lucky that your 'hot'
regulator didn't burn up the generator. I suppose the ultimate setup would be
to measure the internal temperature of the generator (and limit it), perhaps by
measuring the field coil resistance ... but it hardly seems worth the effort to
me...
Randall
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