Q: How do air compressors distinguish between frequency conversion and power frequency?
Answer: The air compressor manufacturer will indicate 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 indicate it on the nameplate, you can refer to the motor nameplate and controller label. On the working panel of the air compressor, you can also check if there is a prompt for variable frequency or power frequency.