At 01:01 PM 8/23/05 -0700, Simon Matthews wrote:
>I have been bothered by a strange noise from my MGA recently.
>
>I think that the noise is the voltage regulator switching very
>quickly -- creating a sound that is almost like a buzzing sound.
>
>Is the regulator supposed to switch this fast?
Yes.
>Or do I have a problem with the regulator?
Probably not.
>.... It seems to happen only when the engine is revving above about
>2500 RPM and it does not seem to change tone with engine speed.
All correct and proper. Regulation is done by (in modern electronic
terms) square wave pulse width modulation. The regulator relay
vibrates rapidly. The frequency does not change much. The relative
time for points open/closed is controling the average voltage output
to the generator field coils. More details here:
http://chicagolandmgclub.com/techtips/general/585.html
Barney Gaylord
1958 MGA with an attitude
http://MGAguru.com
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