Inverter protection of the motor is important in the following aspects: overvoltage protection, undervoltage protection, overcurrent protection, phase loss protection, reverse phase protection, overload protection, grounding protection, short circuit protection, overfrequency protection and stall protection.By setting the inverter parameters to limit the value of motor current, voltage, frequency, etc., the inverter will move beyond the limit value and stop the motor to protect the motor. The fault code on the inverter can be used to find out the cause of protection.
1. Overvoltage protection:
The output of the inverter has the function of voltage testing. The inverter can automatically adjust the output voltage so that the motor does not suffer from overvoltage.Even when the output voltage adjustment fails and the output voltage exceeds 110% of the normal voltage, the inverter can protect the motor by stopping.
2. Undervoltage protection:
When the voltage of the motor is less than 90% of the normal voltage, the inverter stops the machine.
3. Overcurrent protection:
When the current of the motor exceeds 150%/3 seconds of the rated value, or 200%/10 microseconds of the rated current, the inverter protects the motor by stopping.
4. Phase absence protection:
Monitor the output voltage, when the output phase is missing, the inverter alarm, a period of time after the inverter stop to protect the motor.
5. Reverse phase protection:
The frequency converter can be set so that the motor can only twist in one direction and cannot be set. Unless the user tamper with the phase sequence of the connection of motor A, B and C, there is no possibility of inverting the phase.
6. Overload protection:
The inverter monitors the motor current. When the motor current exceeds 120%/1 minute of the rated current, the inverter stops to protect the motor.
7. Ground protection:
The inverter is equipped with special grounding protection circuit, which is usually composed of grounding protection transformer and relay. When one or two phases connect to the ground, the inverter will give an alarm.Of course, if the user requests, we can also plan for grounding after the protection of downtime.
8. Short circuit protection:
Inverter output short circuit, is bound to cause overcurrent, in 10 microseconds by the inverter stop to protect the motor.
9. Overclocking protection:
The frequency converter has a very large and very small frequency limiting effect, so that the output frequency can only be defined within the limitation, thereby realizing the overfrequency protection effect.
10. Stall protection:
Stall protection is generally applied to synchronous motors.As for the asynchronous motor, the stall in the acceleration process must be interpreted as overcurrent, and the inverter achieves the protection effect through overcurrent and overload protection.Stalling during a delay can be avoided by setting a safe delay during debugging.