Single-phase power source circuit e.g. transistor emitter circuit, for automatic switching device in e.g. hospital, has gate circuit controlling main- and reserve relays such that main relays are closed and reserve relays are opened at time

摘要

The circuit has a reserve path (Back-Path) joined between outputs (L, N) and auxiliary inputs (Back-L1, Back-N). The auxiliary inputs are joined to a single stage of a reserve power source. A main relay (K2) is arranged in a main path (Main-Path). A reserve relay (K1) is arranged in the reserve path. A gate circuit (MCU) controls the main relay, another main relay (K4), the reserve relay and another reserve relay (K3) such that the main relays are closed and the reserve relays are opened at same time or the main relays are opened and the reserve relays are closed.