Frequency inverter - switching frequency

[peterl86]

Hi,
i have frequency inverter and induction motor. Switching frequency of inverter can be 2 - 12kHz. Which frequency to select? Motor has no label.

 

[barry]

Your induction motor SHOULD have a label; how do you even know it's an induction motor? In theory, the switching frequency of the inverter should be irrelevant since it will be filtered out and all that appears on the output is a pure sinewave. Obviously this is not reality. If it were me, I'd look at the waveforms across the motor as you vary the switching frequency and see how it performs-you may get resonances, etc., due to the harmonics of the switching.

 

[peterl86]

Your induction motor SHOULD have a label; how do you even know it's an induction motor? In theory, the switching frequency of the inverter should be irrelevant since it will be filtered out and all that appears on the output is a pure sinewave. Obviously this is not reality. If it were me, I'd look at the waveforms across the motor as you vary the switching frequency and see how it performs-you may get resonances, etc., due to the harmonics of the switching.

On the cover there are only traces from label. It's second hand. I will look at the waveforms.

 

[peterl86]

Theoretically depends on what the definition of carrier frequency?Inductance of stator windings?