Patent ID: 9166406
Filing Date: 2015-10-20
Classification: H02J

Abstract:
1. A power source switching circuit, comprising: a first contact, the first contact comprises a first normally open main contact and a first normally closed auxiliary contact, the first normally open main contact configured to be connected between a main power source and a loader; a second contact, the second contact comprises a second normally open main contact and a second normally closed auxiliary contact, the second normally open main contact configured to be connected between an auxiliary power source and the loader; a first relay, and the first relay comprises a first normally open contact and a first normally closed contact; a second relay, and the second relay comprises a second normally open contact and a second normally closed contact; and a third relay, and the third relay comprises a third normally open contact and a third normally closed contact; wherein the first normally open contact, the second normally open contact, and the third normally open contact, connected in series, are configured to be connected between three phase lines of the main power source and the second normally closed auxiliary contact; the second normally closed auxiliary contact is configured to be connected to a zero line of the main power source; the first normally closed contact, the second normally closed contact, and the third normally closed contact, connected in parallel, are configured to be connected between three phase lines of the auxiliary power source and the first normally closed auxiliary contact; and the first normally closed auxiliary contact is configured to be connected to a zero line of the auxiliary power source.