Inverter is widely used in the industrial sector because of its motor protection function, and what is the protection function of inverter to motor?
1. Overvoltage Protection
The output of the inverter is of voltage detection function, it can automatically adjust the output voltage to avoid over-voltage on motors. Even if the output voltage regulator fails or the output voltage exceeds 110% of the normal voltage, the inverter will protect the motor by downtime.
2. Under-voltage Protection
When the motor voltage is less than 90% of the normal voltage, the inverter will also be shut down to protect the motor.
3. Over-current Protection
When the motor current exceeds the rated value of 150% / 3 seconds or it exceeds rated current of 200% / 10 microseconds, the inverter will also be shut down to protect the motor.
4. Open-phase Protection
When the output phase loss, the inverter will alarm for after a while. If the voltage can’t be adjusted to normal voltage, the inverter will also be shut down to protect the motor.
5. Phase-reversal Protection
The inverter make the motor rotate in one direction and the direction can’t be set unless the user changes the phase sequence of the motors A, B, and C wiring.
6. Over-load Protection
The inverter detects the motor current. When the motor current exceeds 120% of the rated current / 1 minute, the inverter protects the motor by downtime.
7. Grounding Protection
The inverter is equipped with a special grounding protection circuit. Generally, the circuit is composed of grounding protection transformers and relays. When there is one phase grounding or two phases grounding, the inverter will alarm. Of course, if the user asked, we can also design instant stop running function when grounding happens.
8. Short-circuit Protection
When short circuit happens to inverter output, it will inevitably lead to over-current. Within 10 microseconds, inverter protects the motor by stop motor running.
9. Over-frequency Protection
The inverter has the maximum and minimum frequency limiting function, which makes output-frequency is within the specified range. In this way, the over-frequency protection function can be realized.
10. Stalling Protection
Stall protection is generally for synchronous motors. For asynchronous motors, over-current must happen during acceleration. The protection function of inverter is realized by over-current and over-load. Stall during deceleration can be avoided by setting a safe deceleration time during commissioning.