Measuring the motor voltage and the motor current by means of a moving coil instrument

Question:

Can the motor voltage and the motor current (at the output of the drive controller) be measured correctly by means of a moving coil instrument?

Answer:

a) Motor voltage:
No. The drive controller presents a pulse-width modulating voltage, which leads to an incorrect display when a moving coil instrument is used. Due to technical reasons the moving coil instrument is not able to detect the effective value. For measuring the effective value only a moving iron instrument is suitable. The drive controller also presents at code C0052 the effective value of the voltage between the motor phases.

b) Motor current:
No, the motor current cannot be measured correctly by means of a moving coil instrument, as due to technical reasons there is a measuring error. For measuring the effective value a moving iron instrument or a digital multimeter (True-RMS) is suitable. The drive controller also presents at code C0054 the effective value of the motor current.

Symbol of the moving coil instrument:

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AKB-ID: 200400385
Last update: 2024/01/11
Category: FAQ, Tips and Tricks

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