2-pole synchronous motor speed is 3000r / min, air compressor asynchronous motor 2 pole speed ≥ 3000 * 97% = 2910r / min. We usually say 2960r / min to the user. 3% is the speed differential .
4-pole synchronous motor speed is 1500r / min, air compressor asynchronous motor 4-pole speed ≥ 1500 * 97% = 1455r / min, We usually say 1480r / min to the user.
Compressor supporting the motor only two poles and four poles. Its speed can be regarded as a constant according to national standards (1480r / min, 2960r / min).