How to distinguish between frequency conversion and power frequency air compressor?

Q: How does the air compressor distinguish between frequency conversion and power frequency?

Answer: The air compressor manufacturer will mark on the nameplate of the air compressor whether it is a power frequency air compressor or a variable frequency air compressor.

If the air compressor manufacturer does not mark it on the nameplate, you can see that the motor nameplate has been labeled with the controller. On the working panel of the air compressor, you can also see if there is a prompt for frequency conversion or power frequency.