How Does Frequency Inverter Protect the Motor?

Frequency inverter is a power control equipment which uses frequency conversion technology and microelectronics technology to control AC motor by changing the working power frequency of motor.

Frequency inverter is widely used in various industries, mainly because of its energy saving and frequency conversion speed regulation function in equipment and operating system application, then from what aspects of the frequency inverter to protect the motor? In this article, will introduce something about this topic. Next we will list ten ways in which the frequency inverter protects the motor.

1.5 kW single phase output frequency inverter

  • Over-voltage Protection. The output of single phase frequency inverter has voltage detection function, frequency inverter can automatically adjust the output voltage, so that the motor does not bear overvoltage. The converter protects the motor by stopping even when the output voltage adjustment fails and the output voltage exceeds 110% of the normal voltage.
  • Under-voltage Protection. When the voltage of the motor is less than 90% of the normal voltage, the inverter protection stops.
  • Over-current Protection. When the motor's current exceeds 150% of the rated value for 3 seconds, or 200% of the rated current for 10 microseconds, the inverter protects the motor by shutting down.
  • Open-phase Protection. Monitor the output voltage. When the output is out of phase, the frequency inverter will alarm. After a period of time, the frequency inverter will stop to protect the motor.
  • Phase-reversal Protection. The inverter makes the motor rotate in only one direction, and cannot set the rotation direction. Unless the user changes the phase sequence of the wiring of the motor A, B and C, there is no possibility of reversing the phase.
  • Overload Protection. The converter monitors the motor current and protects the motor by shutting down when the motor current exceeds 120% of the rated current / 1 minute.
  • Ground Protection. The frequency inverter is equipped with a special ground protection circuit, which is generally composed of ground protection transformer and relay. When one or two phase ground contact occurs, the frequency inverter will alarm. Of course, if the user requires, we can also be designed to protect the shutdown immediately after grounding.
  • Short-circuit Protection. The short circuit of the converter output will inevitably cause overcurrent, and the converter will stop to protect the motor within 10 microseconds.
  • Over-frequency Protection. Frequency inverter has maximum and minimum frequency limit function, so that the output frequency can only be in the specified range, thus realizing the overfrequency protection function.
  • Stall Protection. Stall protection is generally aimed at synchronous motors. For asynchronous motor, the stall in the acceleration process is bound to be overcurrent, and the frequency inverter realizes this protection function through overcurrent and overload protection. Stalling during deceleration can be avoided by setting a safe deceleration time during debugging.
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