See the schematic in Fig. 1. This relay uses a 30A DPDT relay (Magnecraft 300XBXC1-120A) to route utility or UPS power to the loads. When the UPS is providing output voltage, it energizes the relay ...

DPDT relay applications 1. Change motor direction with DPDT relay. As you can see in the schematic the 12V battery (or use other voltages) is connected with the plus at terminal T1 and minus at ...

He uses DPDT, not SPDT relays :-D At this moment, I finish a relays/diodes only hexadecimal display, using only Russian parts (because I can).