VFD output voltage measurement

K

Thread Starter

K C Oh

Hi all,

I like to know is there a way to use true rms fluke meter to measure the output from VSD output.
I had tried but the readings are offset by 50V or more.

Eg. a 400V supply input supply, VSD running at 50Hz output measured voltage using meter is 455V, but the display shows 399V.

Thank you
 
H

Hakan Ozevin

Output waveform of a VFD is PWM at no less than 2 kHz pulse frequency, so even true rms multimeters cannot correctly show it. Rely on the VFD display or use an oscilloscope.
 
The supply current is always much lower than output current. What is the calculations methods used?
 
A

Allabaksh Naikodi

There are some three phase power analysers used for the efficiency evaluation of the voltage source inverters. They can be tried out to get very close rms value of output voltage.
 
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