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how to make a shaft power meter? Answered

I need to measure the shaft power output of a small motor. How to do that? Most machine on the market are to measure large shaf power output, such as of a car or motorcycle engine. My power output is estimated to be about 2kW.

Any suggestion would be of help to me.

Thank you.

Regards,
Wan

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The simplest classic method, if you don't need continuous readings, is to put a metal drum on the output shaft, usually hollow, so it can hold water, and with a band wrapped round it to a weight. The friction on the drum (whose radius can be measured) is related to the weight, so a torque is exerted on the shaft. Measure shaft speed and you have all you need.

Another method, for a continuous process, would mount the motor in bearings, so that the motor can twist about its axis, A set of springs resist the motion, and a measurement of twist angle is proportional to torque. Calibration is against a series of weights, applied at known radius.

You need it to do some work. For example drive a generator dumping energy into a load - you measure current and voltage. You could do a torque measurement and derive from there, but I think electric easier.

L