Three phase unbalance of distribution network that can not be ignored

The circuit is simple in structure, and the disadvantage is that the operation of SB1 can cut off the input main power supply when the frequency converter is working normally, so it is easy to damage the frequency converter.

 

2. relay control positive and reverse control circuits

 

The KA1 and KA2 relay are used to carry out positive and reverse control respectively.

 

(the description of the work process has been omitted)