Electronic – A very basic question about VFD output frequency

induction motorvfd

I know that a VFD's inverter stage creates alternating voltages at a desired frequency for the terminals of a delta induction motor(stator voltage freq.).

Normally without a VFD the nominal freq. for the motor terminal voltages are 50/60 Hz rated.

In case of VFD use, will the induction motor terminals(stator terminals) voltage frequency be limited to 50/60Hz? On the other hand I see such data where the VFD electrical output freq. is given upto 590Hz as follows:

enter image description here

Induction motors are manufactured for 50/60Hz systems. How come 590Hz limit possible for safe operation? Am I misunderstanding something here?

Best Answer

When you're setting up a Variable Frequency Drive (VFD) you will configure things like the min/max frequency, rated voltage, rated full-load amperage, and accel/decel time. Depending on how fancy of a VFD you've got, there could be dozens of other settings (comms., safety, digital inputs/outputs, control methods, etc).

As mentioned in some comments, many industrial motors are manufactured to 50/60 Hz depending on your geography, but this is not true of ALL motors. I believe ships and planes use higher frequency. Wikipedia says that spacecraft, submarines, machinery, and military equipment may be run on 400 Hz. Motors run at 400 Hz can provide similar power for a smaller size.

To answer your question -- 590 Hz out of the VFD is possible, but it is not safe for the operation of a 50/60 Hz motor. In this scenario, you would configure the VFD to 50/60 Hz. If you were using a 400 Hz motor, you would configure the VFD to 400 Hz.