... current with 380V, 660V, 50HZ,which is mainly used for power distribution and infrequent changing over; and protection ... signal W4; W1,W2,W3,W4 is just used for frame level 1,2 and 3. and short circuit ... release is used for all series. If need, it can ... order according to his need.Blocking solenoid is mainly used for the protection of circuit breaker of motor. ...