... sequence voltage protection device 1,Phase Loss protection 2,Phase sequence protection 3,Phase unbalance protection JVRDphase sequence voltage protection device(Voltage and ... voltage protection, etc.) mainly for the exchange of 50/60Hz, rated voltage 460V below, industrial three-phase 220V, 380V ... circuit: 1. can not be separated with a electrical normally open and one normally closed contact. 2. ...