To provide a unit and a system capable of being subjected to connection/disconnection of a connectors without depending upon manual operation by providing respectively such as particular power supply connector unit, a power supply receiving connection unit, a connection releasing means and a control unit.

Such connection/release means and a control unit are provided wherein the connection/release means includes a connection part for power supply which is a male type connector connecting piece 3a to be connected to a connector 1 for power supply provided on a front surface, a connection part for power receiving which is a female type connection hole 3b for connecting a power receiving side connector 2 provided on the rear surface, an extruded material 9 coming into contact with a power supply side connector 1 in such a state as projecting toward the connector for the purpose of releasing the connection between the power supply connector 1 and the connection part 3a for power supply, a spring 11 for energizing the material 9 to its projecting state and a solenoid 6 for retreating and engagingly locking the material 9. The control unit encloses a receiving unit for receiving a connection release signal from a remote controller 4 so as to include such a function as forcing a connection releasing means to make its releasing operation by means of the connection release signal.