873EC-JIPFGZ-FOXBORO module
Function: It is mainly used to quickly cut off the power supply when personal electric shock or leakage occurs, to ensure personal safety and prevent electric shock accidents. Some leakage protectors also have overload and short circuit protection, which are used for infrequent starting and power failure motors.
Working principle: When working normally, regardless of whether the three-phase load is balanced, the sum of the three-phase current phasors through the main circuit of the zero-sequence current transformer is equal to zero, so no induced electromotive force is generated in the second winding, and the leakage protector works in the closed state. If a leakage or electric shock occurs, the sum of the three phases of the current is no longer equal to zero, but equal to a certain current value 1s. ls will form a loop through the human body, the earth and the neutral point of the transformer, so that the induced electromotive force corresponding to Is will be generated on the secondary side of the zero-sequence current transformer and added to the trip device. When Is reaches a certain value, the trip device will act to push the lock of the main switch and break the main circuit.