Power transmission systems 71A, 71B, 71C connected to connectors 59A, 59B, 59C are all caused to join with a common system 73 at a junction before being connected to a control unit 35. The power transmission systems 71A, 71B, and 71C include switches 74Aa, 74Ab, 74Ba, 74Bb, 74Ca, 74Cb. In relay circuits 75A, 75B, 75C, when a plug for an external power supply is connected to corresponding one of the connectors 59A, 59B, 59C, connection of the corresponding connector connection detecting terminals and plug connection detecting terminals energizes a coil of the corresponding control relay (either 76A, 76B, or 76C), then after switching contact points of the corresponding control relay to a closed state, energizes coils of the corresponding switches via the contact points, and switches contact points of the corresponding switches to a closed state.
Electric construction machine
2018-02-13
Patent
Electronic Resource
English