Re: [Q] Shaft speed measurement (again, based on response)

[David Roden <roden@ACORN.NET>]

>
> >From the suggestions I see that I might need to take direct measurements
> somehow. As a consolation for this could someone please tell me how this
> is done in cars.

In the old days the tach connected across the breaker points and counted
pulses.  I imagine that now the engine computer supplies the tach a
voltage proportional to engine speed, but I don't know.  Hmmm, knowing how
automakers hate to change things, the computer probably feeds the tach
pulses that look like breaker-point pulses!

One of the EV parts dealers -- I think either Electro Automotive or KTA
services, maybe both, maybe others too -- sell(s) an adapter which counts
the passing blades on the ADC fan and feeds a signal to your tach.  I
think it also includes a rev limiter to cut out the power in case you
overspeed the motor.

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   David Roden         THE VIRTUAL PD            roden@acorn.net
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Re: [Q] Shaft speed measurement (again, based on response)                   R