The protective effect of frequency converter on permanent magnet motor

1. Overvoltage protection

The inverter output has an automatic voltage stabilization function, which can control the output voltage not to exceed the rated voltage of the permanent magnet synchronous motor when the external power input is too high.

2. Under voltage protection

When the voltage of the permanent magnet synchronous motor is lower than 90% of the normal voltage, the inverter enters the protection permanent magnet synchronous motor output mode and reduces the output frequency; when the voltage of the permanent magnet synchronous motor is lower than 65.2% of the normal voltage, the motor is stopped.

3. Overcurrent protection

When the current of the permanent magnet synchronous motor exceeds the rated value range, the inverter protects the permanent magnet synchronous motor by stopping.

4. Phase loss protection

Monitor the output voltage. When the output phase is missing, the inverter will alarm. After a period of time, the inverter will stop to protect the permanent magnet synchronous motor.

5. Overload protection

The frequency converter monitors the current of the permanent magnet synchronous motor. When it exceeds the rated current of the permanent magnet synchronous motor, it will protect the motor by accumulating heat calculated by the inverse time curve. When the permanent magnet synchronous motor exceeds 2 times the rated current and reaches 1 minute, the frequency converter will The controller protects the motor by shutting down.

6. Ground protection

It is generally composed of a grounding protection transformer and a relay. When one or two phases are grounded, the frequency converter will alarm.

7. Short circuit protection

After the inverter output is short-circuited, it will inevitably cause overcurrent. The inverter will shut down within 10 microseconds to protect the permanent magnet synchronous motor.

8. Overclocking protection

The frequency converter has small and small frequency limiting functions, so that the output frequency can only be within the specified range, thus realizing the overclocking protection function.