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The speed control motor has a weak work and the sound is increasing. What should we do?
- 2019-03-12-

If the speed-regulating motor is incapable of working and the sound is increased, it is first necessary to measure the output voltage of the inverter. Because the output voltage is proportional to the output frequency, the voltage is not a asserted value, but the three-phase voltage is balanced. So measuring the output voltage is actually measuring whether the three-phase voltage is balanced or disconnected. The output voltage of the inverter is unbalanced, mainly because the switch bridge arm is poor or damaged, and the output voltage is out of phase or unbalanced.

Regarding the overvoltage problem of the inverter, if there is no feedback energy, the general voltage will not exceed 540V, which exceeds this value, and most of the inverter has returned energy. In some cases, the reason why the inverter generates feedback energy is not obvious. The voltmeter can be connected for a long time, supervise the voltage on the DC bus, investigate when the voltage rises, and whether there is a corresponding connection between the operation status of the load, etc. To determine the source of the overvoltage.

The method of measuring the DC bus voltage is to hit the 47-type multimeter to 1000V DC file and measure the voltage across the DC bus. Generally, the over-voltage alarm value of the inverter is planned to be between 700~780V. When the measured value is within this scale, the description is The inverter did have an overvoltage problem. If the voltage is below 540~700V and it is at normal scale, it is the false detection of the voltage detection circuit of the inverter. The inverter has a false alarm that the DC bus voltage has exceeded 540V, but the alarm has not yet reached the set value of the overvoltage alarm. If the carrier frequency setting of the inverter is too low, the carrier frequency can be set higher, but this will bring some problems. If the carrier frequency is adjusted too high, it will cause interference to other devices, especially when selecting When the PLC communication method. Therefore, the carrier frequency should be set according to the actual situation on site.

If the three-phase output voltage of the inverter is balanced and continuous, the reason is in the geared motor itself. This time is to find the cause or deal one by one.

When looking for problems from the motor itself, we must first look at the speed control motor is a few phases, if it is a single-phase motor; check whether the capacitor is damaged, if it is a three-phase motor; check to see if there is a problem with the winding. The motor can be loaded with load to drop. If the geared motor is used for a long time, or the motor quality is not good, the load can be reduced. At this time, the noise of the motor will be larger than normal. If the geared motor cooling fan is damaged or the motor casing is scraped, the motor is not fixed. In general, if you can do it in a defense-proof manner, prevent pre-combination, solve problems, and deal with problems, it will be beneficial to the durability of the geared motor.