The motor noises nothing more than for two reasons: mechanical and electrical.

    1 mechanical

    Such as damage or scratch the motor cooling fan motor housing, motor fixed unstable. The situation in this regard is a good deal, if I could find the source of the noise, generally a good deal.

    2 electrical

    (1) the carrier frequency of the inverter is set too low

    Appropriate carrier frequency is set higher, but this time will cause some problems if the carrier frequency is so high that they cause interference to other equipment, especially when the the PLC communication mode. Therefore, according to the actual situation in the field to set the carrier frequency.

    (2) Motor resonance

    Sometimes, when the motor is running a particular band will produce a mechanical resonance. Then you can use the method of the inverter frequency hopping set. General inverter has a "frequency hopping" set, whose role is to: Set the resonance frequency of the motor, When inverter operation this band, skip this paragraph frequency to avoid the motor resonance.

    (3) motor with a load capacity reduced

    Sometimes the motor after prolonged use, or poor quality motor, with a load capacity will be reduced. Motor noise than normal.

    (4) high harmonics of the inverter

    Inverter high-order harmonic components, likely to cause motor vibration increases, the speed to produce jitter, unstable, and increased motor noise. Installation of AC (the input side) and DC (output side) of the reactor.