Why does the scroll refrigeration compressor reverse? What about reversal?
We know that the operation of the internal compression structure of the refrigeration compressor has a fixed direction. First of all, we need to make it clear: the occurrence of reverse rotation must be unfavorable for the refrigeration compressor. Scroll refrigeration compressors can only compress in one direction of rotation. Single-phase compressors always start and run in the correct direction (except for momentary power failure). The rotation direction of the three-phase compressor is determined by the phase sequence of the power supply, so the compressor has a 50% probability of reversing When installed on site, it can be judged that the refrigeration compressor rotates in the correct direction based on the decrease in suction pressure and the increase in discharge pressure. In addition, if the compressor is reversed, the compressor noise is abnormal and the operating current is significantly lower than normal operation. However, long-term reverse rotation will damage the refrigeration compressor. The equipment manufacturer can install a phase sequence protection module in the control loop to ensure that it does not operate in the case of an incorrect phase sequence. Generally speaking, the scroll compressor only needs to exchange any phase in the three-phase line to operate normally. There is a situation that will cause the refrigeration compressor to reverse, that is; instantaneous power failure. Instantaneous power failure (the power failure time is less than 0.5 seconds) may cause the rotation direction of the single-phase compressor to change. After the power is turned on again, the compressor will continue to run in the reverse direction for a few minutes until the compressor motor protector operates. This has no effect on the compressor. After the motor protector is reset, the compressor will restart and run in the correct direction. It is recommended to use a relay that can sense instantaneous power failure. When a momentary power failure occurs, lock the compressor for two minutes before allowing the compressor to restart.
