Why does the motor with frequency converter vibrate?

It may be caused by the following reasons!

1. The encoder signal detection is inaccurate, or the signal line contact is not good. Check the encoder itself, and then check the connection of the signal line.

2. When the motor resonates, it is necessary to set the jump frequency of the inverter. Setting this parameter means, for example, if 10-14 is set as the jump frequency, the inverter will not output a frequency of 10-14Hz and will skip directly.

Hop frequency function:

Generally, general-purpose inverters have 3 (or more) frequency jump points. That is to say, if the inverter runs at a certain frequency (for example, 13Hz) and the motor resonates, you can set the inverter parameter jump frequency (or avoidance frequency, refer to the manual for details) to this frequency (for example, 13Hz), and then set the amplitude (for example, plus or minus 1Hz). In this way, the inverter will not run within the range of 13-1=12Hz and 13+1=14Hz.

For example, during acceleration, if you set 12.5Hz, the inverter will run at 12HZ, and if you set 13.5Hz, it will also run at 12HZ; if you set 14HZ or above, it will run at 14HZ or above. If during deceleration, if you set 13.5HZ, the inverter will still run at 14HZ, and if you set 12.5HZ, it will run at 14HZ; if you set 12HZ or below, it will run at 12HZ or below. Please read the instructions carefully and contact the manufacturer.

Solution to the vibration caused by the inverter driving the motor

Take the analysis of jitter generated when the motor is driven by Mitsubishi inverter as an example, as follows:

1. Mechanical resonance

Cause: The vibration caused by mechanical resonance will affect the control of the inverter, resulting in unstable output current (torque). According to the control block diagram (as shown below), the output current (torque) fluctuation can be reduced by changing the output frequency, thereby reducing vibration.

The processing steps are as follows:

1. Set Pr.653 to 100%, run the machine for a few seconds at the operating frequency with the maximum vibration, and check whether the vibration is relieved.

2. If there is no effect, please gradually increase the setting value of Pr.653, run repeatedly and confirm the effect, and use the value with the most obvious effect as the final setting value (Pr.653).

3. If the vibration is larger after increasing Pr.653, please gradually reduce Pr.653 from 100% and confirm the effect in the same way.

2. The power supply high-order harmonics are too large

Reason: The high-order harmonics of the power supply are generated by the rectifier part of the inverter, which will affect the generator and the phase-advancing capacitor, etc. The source, frequency range and transmission path of the high-order harmonics are different from those of noise and leakage current.

Treatment method:

1. Install the reactor

2. Wiring diagram

3. The inverter generates noise

Cause: Since the inverter outputs intermittently at a high carrier frequency, it becomes a source of noise. This noise causes the peripheral equipment to malfunction.

Treatment method:

1. Avoid parallel wiring and bundle wiring of the inverter power line (input and output lines) and signal lines. The wiring should be dispersed.

2. Use twisted-pair shielded wires for the detector's connection wires and control signal wires, and connect the sheath of the shielded wires to the SD terminal.

3. Install surge suppressors on machines that generate more noise to suppress the occurrence of noise, and install data line filters on signal lines.