400 HZ AIRCRAFT GROUND POWER SUPPLY

摘要

400 Hz aircraft ground power supply with a three phase AC power source connectable via an electric power relay and flexible cable provided with a socket connector to a plug connector at the aircraft is disclosed. In the energizing circuit of the power relay is arranged a closing contact of a second electric relay, the energizing circuit of which is led via switching means at the socket connector to be actuated by a pin of the plug connector. Thus the closing contact of the second relay is opened as long as the socket connector is not plugged to the plug connector. A third electric relay energized via the connectors by a source of DC current on board the aircraft has a closing contact in parallel to the closing contact of the second relay in the energizing circuit of the power relay and further opening contacts disconnecting a separate source of voltage in the energizing circuit of the second relay if the third relay is energized.