# Measurement of power associated witha vertical shaft

## Main Question or Discussion Point

How can I measure the power associated with a vertical rotating shaft (similar to the shaft of a vertical axis wind turbine).
power=Torque*angular velocity
Angular velocity can be found by using tacho meter or spectroscope.. but i am confused how to measure the torque...

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The only correct answer is with difficulty. Also how much do you have to spend and how accurate do you need to be? You might do it directly by measuring the twist in the shaft, I've seen this done in two ways.
A) You have two toothed wheels at either end of a torque tube by looking at the phase change of the waveform from magnetic pickups on each wheel you can calculate the twist of the tube.
B) You have a scribed line on a torque tube, by looking at the line, under a strobe light so the line appears stationary, through a microscope with a suitable grid and thus measuring the twist.
In both cases you need a calibrated torque tube.
Depending on what you are driving you might be better calculating the power from the driven device.

russ_watters
Mentor
Is there a load connected to it?