Inverter protection to the motor

The frequency converter protects the motor mainly in the following aspects: Overvoltage protection, undervoltage protection, overcurrent protection, phase loss protection, reverse phase protection, overload protection, ground protection, short circuit protection, overclock protection and stall protection. Here is a brief introduction of how these types of inverters protect the motor.

1. Overvoltage protection:

The output of the inverter has a voltage detection function, and the inverter can automatically adjust the output voltage so that the motor does not withstand overvoltage. Even if the output voltage adjustment fails and the output voltage exceeds 110% of the normal voltage, the inverter protects the motor by stopping.

2. Undervoltage protection:

When the voltage of the motor is lower than 90% of the normal voltage, the inverter protection stops.

3. Over current protection:

When the current of the motor exceeds 150%/3 seconds of rated value or 200% of rated current, the inverter protects the motor by stopping.

4. Phase protection:

Monitor the output voltage. When the output is missing phase, the inverter alarms. After a period of time, the inverter protects the motor by stopping.

5. Reverse Phase Protection:

The inverter can only rotate the motor in one direction, and cannot set the rotation direction. Unless the user changes the phase sequence of the motor A, B, C wiring, there is no possibility of inversion.

6. Overload protection:

The inverter monitors the motor current. When the motor current exceeds 120%/1 minute of the rated current, the inverter protects the motor by stopping.

7. Ground protection:

The frequency converter is equipped with a special grounding protection circuit. It is generally composed of grounding protection transformers and relays. When a phase or two-phase grounding occurs, the inverter alarms. Of course, if the user requests, we can also design the protection immediately after grounding.

8. Short circuit protection:

Inverter output short circuit, it will inevitably cause over-current, in 10 microseconds the inverter through the shutdown to protect the motor.

9. Overclock protection:

The frequency converter has maximum and minimum frequency limits, so that the output frequency can only be within the specified range, thus achieving overclock protection.

10. Stall protection:

Stall protection is generally for synchronous motors. For asynchronous motors, the stall in the acceleration process must be an overcurrent. The inverter implements this protection function through overcurrent and overload protection. Stalling during deceleration can be avoided by setting a safe deceleration time during commissioning.