Inverters are widely used in various industries, mainly because of their energy-saving and frequency conversion speed regulation functions in equipment and working conditions systems. So from what aspects does the inverter protect the motor? Let's move on.
The protection of the inverter to the motor mainly focuses on overvoltage protection, undervoltage protection, overcurrent protection, phase loss protection, reverse phase protection, overload protection, grounding protection, short circuit protection, overfrequency protection and stall protection. The following is a brief introduction to these protection methods.
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 bear overvoltage. Even when the output voltage adjustment fails and the output voltage exceeds 110% of the normal voltage, the inverter will protect the motor by shutting down.
2. Under voltage protection:
When the voltage of the motor is lower than 90% of the normal voltage, the inverter will stop for protection.
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 shutting down.
4. Phase loss protection:
Monitor the output voltage. When the output phase is missing, the inverter will give an alarm. After a period of time, the inverter will stop the motor to protect the motor.
5. Reverse Phase Protection:
The inverter can only rotate the motor in one direction, and cannot set the direction of rotation. Unless the user changes the phase sequence of the motor A, B, and C wiring, there is no possibility of inversion.
6. Overload Protection:
The inverter monitors the motor current, and when the motor current exceeds 120% of the rated current/1 minute, the inverter protects the motor by shutting down.
7. Ground protection:
The inverter is equipped with a special grounding protection circuit, which is generally composed of a grounding protection transformer and a relay. When one or two phases are grounded, the inverter will alarm. Of course, if the user requests, we can also design to protect the shutdown immediately after grounding.
8. Short circuit protection:
After the inverter output is short-circuited, it will inevitably cause overcurrent, and the inverter will stop to protect the motor within 10 microseconds.
9. Overclocking Protection:
The inverter has the maximum and minimum frequency limit function, so that the output frequency can only be within the specified range, thus realizing the overclocking protection function.
10. Stall Protection:
Stall protection is generally for synchronous motors. For an asynchronous motor, the stall during acceleration must be manifested as overcurrent, and the inverter realizes this protection function through overcurrent and overload protection. Stalls during deceleration can be avoided by setting a safe deceleration time during commissioning.
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