# Mach3 Spindle Rpm



## Blackhawk (Apr 23, 2015)

having a problem with rpm dropping by half?


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## JimDawson (Apr 23, 2015)

Maybe your pick up or input is not fast enough to keep up.  Maybe it's being overloaded with pulses.  The other possibility is that the tab is not wide enough and the signal is too fast at higher RPMs.  Try making a tab that is much longer, maybe a full half arc.


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## Boswell (Apr 23, 2015)

This looks exactly what I would expect if the pulse rate from the sensor was too fast for the computer to count so it starts missing pulses and counting every other pulse and then it starts missing 2 out of three.   Bottom line is I agree with Jim on the issue. Another possible option in addition to what Jim suggested would be to find a gear in the gear train that is spinning slower that you can use to measure the RPM.


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## Blackhawk (Apr 23, 2015)

Thanks for the replies, I'll make one with a bigger tab


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## Blackhawk (Apr 28, 2015)

Made a new one with a bigger tab, works perfect except for vibration, at 1600 rpm the lathe starts walking off the stand. Lol
Thanks for the help


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