[Farmall] Tachometer

[Robert L. Holtzer]

Thanks for the response.

Bob Holtzer

At 06:37 PM 12/20/2004 -0500, you wrote:
>There are at least two different versions of those counters.  One counts 
>for exactly 1 second, 1 minute,
>or ten minutes and resets.  The counting window is switch selectable.
>
>The other counts as long as it is able to detect the trigger pulse.  On 
>those, you normally use a stop watch
>and count for a period of 1 minute or several - then do the math to 
>translate the result to RPM.
>
>Most that I have worked with are triggered by a small piece of reflective 
>tape (foil) that is stuck on the
>rotating machinery somewhere.  The sensor (triggered by light) is aimed at 
>the tape.  It picks up the reflected
>light from the tape each time it passes and counts or accumulates 
>them.  They can be very accurate as long
>as the sensor is reliably triggering on the tape.  That can be helped by 
>shining a light at the tape.
>
>They will measure the RPM of most anything that you can stick the tape to.
>
>Howard
>
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