| 摘要 |
A power source switching apparatus according to the present invention comprises: a controlling part to output a normal power source supply signal and a midnight power source supply signal selectively according to the midnight power source conduction state; a normal power source control relay which includes a first type contact and a second type contact, and operates by the normal power source supply signal; a normal power source supply relay to supply a normal power source to a load, and is switched on according to the operation of the normal power source control relay; a midnight control relay which includes the first type contact and the second type contact, and operates by the midnight power source supply signal; and a midnight power source supply relay to supply a midnight power source to a load and is switched on according to the operation of the midnight power source control relay. The first type contact of the normal power source control relay and the second type contact of the midnight power source control relay are connected serially, and the second type contact of the normal power source control relay and the first type contact of the midnight power source control relay are connected serially. Accordingly, an interlock control is materialized through contact interlocking of the relay, therefore a phenomenon of supplying the midnight power source and the normal power source at the same time can be prevented basically, the system may be protected effectively, and the stability of the system may be enhanced. |
