When using a frequency converter to drive a motor, we often encounter situations where the motor is noisy. There are essentially two reasons for this: mechanical and electrical.
1. Mechanical aspects
For example, a damaged or scratched motor cooling fan, or an unstable motor mounting. These issues are relatively easy to resolve; once the source of the noise is located, they are generally easy to fix.
2. Electrical aspects
(1) The inverter carrier frequency is set too low
It's possible to set the carrier frequency higher, but this can cause problems. If the carrier frequency is set too high, it can interfere with other devices, especially when using PLC communication. Therefore, the carrier frequency should be set according to the actual site conditions.
(2) Motor resonance
Sometimes, a motor may experience mechanical resonance at a certain frequency during operation. In this case, the frequency hopping setting of the frequency converter can be used. Most frequency converters have a "frequency hopping" setting, which allows you to set the frequency at which the motor resonates. When the frequency converter operates at this frequency, it skips this frequency range, thus preventing the motor from resonating.
(3) Reduced motor load-carrying capacity
Sometimes, after prolonged use, or if the motor is of poor quality, its load-bearing capacity will decrease. This will also cause the motor to be noisier than normal.
(4) High harmonics of frequency converter
When the inverter has a large high-order harmonic content, it can easily cause increased motor vibration, speed fluctuations and instability, and increased motor noise. Therefore, AC (input side) and DC (output side) reactors are installed here.
