If you are in the US with 60 cycle AC you can use an electric light. Just
shut out all ambient light and run the engine at some multiple of 60 RPM and
the fan should appear to stop.
George
>>
Hi George:
Have you tested this method? I have done a lot of lamp testing and the
filament (if you are talking about incandescent lamps), will glow quite
bright even during the zero crossing of the 60 Hz. So doubt if you will see
a "strobe" effect at all. Also remember the lamp filament is actually
turning on at 120hz, since it will pass current during both peak phases of
the 60Hz (or 50 in Europe and Australia), so if you were to choose a
multiple, such as 5 X 60 = 300 RPM, it would not be as distinctive as say 3
X 120 = 360 RPM. And of course you would not really know what RPM the engine
was "actually" turning, without a reference.
Wasn't there just a long post by some chap who took the time to do a very
detailed write-up of his MG electric speedo calibration? His was, by my
humble reckoning, the best method I have seen while subscribing to the list
these past two years. The test equipment he used was readily available from
any friend who does electronic repair.
Kind regards,
Tim Economu
Senior Design Engineer
Offgrid Engineering LLC
1969 MGBGT mona
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