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Measuring RPM of a small motor

Measuring RPM of a small motor

Measuring RPM of a small motor

(OP)
Hi!~

It's too small to measure RPM with a optical tachometer.

Is there any method to get RPM of a small motor?

Thanks in advance...

RE: Measuring RPM of a small motor

You can get the surface speed of a shaft with a laser velocimeter. Whether it could focus on such a small shaft is an interesting question.

Perhaps you could look at the drive current with a scope, or analyse the nosie it makes?

Cheers

Greg Locock

RE: Measuring RPM of a small motor



if it is really small and turning slowly, use a stop watch...

RE: Measuring RPM of a small motor

How about a small mark on the shaft and a strobe light?

RE: Measuring RPM of a small motor

Bluenoted,

I've got a mechanical rotation counter in my toolbox.  It is made by Starrett.  It comes with several different sized small rubber couplings that you hold against the shaft.  Run it for a fixed amount of time and do the division and you get the speed. You can probably find one at a tool dealer.

Timelord

RE: Measuring RPM of a small motor

Your motor is probably fastened onto a drive.Perhaps it would be easier to measure the RPM somewhere on the drive. With a tinny color strip on a rotating part of the drive you can measure rotational frequency and calculate the RPM of the motor.
m777182
 

RE: Measuring RPM of a small motor

You can always put an accelerometer on it or nearby,  and find the rotational frequency.
If it's not clear from that,  unbalance it slightly,  then try again!

RE: Measuring RPM of a small motor

If it's a commutated motor, we have two products that measure motor speed from commutation current.  The first product is older technology, model CRSM1, but we have a new, not-yet-announced product that can track motor speed well enough to allow it to do time-domain averaging of vibration caused by the motor's imbalance.... Contact me for more info if your motor is commutated.... eraftery@cdasys.com

RE: Measuring RPM of a small motor

I don't know what kind of motor it is.
May be you can try this software, it works 30 days in demo mode.

http://www.esser.u-net.com/rpm.htm

It uses sound card and microphone.



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