Inverter Protection of the motor

- Oct 11, 2017 -

Inverter is widely used in various industries, mainly because of its energy-saving and frequency control function in the equipment and operating system applications, then the inverter from which aspects of the motor to play a protective role? Here we will analyze this issue to answer.

   Inverter protection of the motor mainly in the following areas: over-voltage protection, under voltage protection, over-current protection, phase protection, reverse protection, overload protection, ground protection, short circuit protection, overclocking protection and stall protection. Here are a few of the inverter on the motor protection mode for a brief introduction.

1. Overvoltage protection:

   The output of the inverter has voltage detection function, the inverter can automatically adjust the output voltage, so that the motor does not withstand over-voltage. Even when the output voltage regulation fails and the output voltage exceeds 110% of the normal voltage, the inverter will protect the motor by downtime.

2. Undervoltage protection:

   When the motor voltage is less than 90% of the normal voltage, the inverter protection shutdown.

3. Overcurrent protection:

   When the motor current exceeds the rated value of 150% / 3 seconds, or rated current of 200% / 10 microseconds, the inverter through the shutdown to protect the motor.

4. Phase protection:

   Monitor the output voltage, when the output phase loss, the inverter alarm, after a period of time through the inverter to protect the motor.

5. Inversion protection:

   The inverter can only rotate the motor in one direction, can not set the direction of rotation, unless the user changes the motor A, B, C wiring phase sequence, otherwise there is no possibility of reverse.

6. Overload protection:

   The inverter monitors 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 composed of grounding protection transformers and relays, when a phase or two phase ground, the inverter alarm. Of course, if the user requests, we can also design a ground protection immediately after the shutdown.

8. Short circuit protection:

   Inverter output short circuit, will inevitably lead to overcurrent, in 10 microseconds through the inverter to protect the motor.

9. Overclock protection:

   The frequency converter has the maximum and minimum frequency limiting 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 asynchronous motors, the stall during acceleration is necessarily overcurrent, and the inverter protects this function by overcurrent and overload protection. Stall during deceleration can be avoided by setting a safe deceleration time during commissioning.

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