1. When the overvoltage relay coil is at the rated voltage, the armature does not close. When the coil voltage is higher than the rated voltage, the armature operates and closes. Then, when the circuit voltage drops to the relay release voltage, the armature returns to the release state. The voltage release value of the overvoltage relay is lower than the operating value, and the adjustment range of the pull-in voltage is 1.05 to 1.2UN.
2 When the coil voltage of the undervoltage relay is lower than the rated voltage, the armature will engage. However, when the coil voltage is very low, the armature will be released.