Y-△ step-down starting circuit three with protection function to prevent arcing and short circuit

(3) Y-△ step-down starting circuit three with protection function to prevent arcing short circuit     . The circuit is shown in Figure 3-44. This circuit can ensure a sufficient time interval during the Y-△ step-down starting process, thereby completely eliminating arcing short circuits between contactor contacts. Two pairs of contacts in series in the contactor KM3 coil control loop can ensure this time interval.