Bobet in stock BLF5782 brushless DC motor with NMRV30 self lock gear

In recent years, permanent magnet variable frequency screw air compressor has been trusted by more and more customers because of its high efficiency, energy saving and stable pressure. However, the manufacturers of permanent magnet motors in the market are uneven, and improper selection may lead to the risk of loss of excitation of permanent magnet motors. Once loss of excitation occurs, permanent magnet motors can only be replaced, resulting in high maintenance costs. How to judge whether the permanent magnet motor loses excitation?
When the machine starts running, the current is normal. After a period of time, the current becomes larger. After a long time, the inverter will be reported as overloaded. First of all, it is necessary to make sure that the frequency converter of the air compressor manufacturer is selected correctly, and then confirm whether the parameters in the frequency converter have been changed. If there is no problem with both, it is necessary to judge by back EMF, disconnect the nose from the motor, make no-load identification, and run to the rated frequency at no load. At this time, the output voltage is back EMF. If it is lower than the back EMF on the motor nameplate by more than 50V, the demagnetization of the motor can be determined.

2 After demagnetization, the running current of permanent magnet motor will generally exceed the rated value. Those cases that only report overload when running at low speed or high speed or occasionally report overload are generally not caused by demagnetization.

3 The demagnetization of permanent magnet motor takes a certain time, some months or even one or two years. If the manufacturer’s wrong selection leads to current overload, it does not belong to the demagnetization of motor.

4 Reasons for demagnetization of motor
The motor’s cooling fan is abnormal, resulting in high temperature of the motor.
The motor is not provided with a temperature protection device.
The environment is too high.
The motor design is unreasonable.