In the embodiment shown in FIGS. 9-16, the electrical apparatus comprises a washing machine 2 and the pivotal part 120 is a washing machine door which is mounted on the main body 110 of the washing machine 2 by a hinge device 112. As shown in FIGS. 9-12, in an embodiment, the first coil 111 acts as a transmitter coil and is in a cylindrical shape and the second coil 121 acts as a receiver coil and is in a hollow cylindrical shape. The transmitter coil at least partially passes through the receiver coil and the receiver coil is pivotally moved relative to the transmitter coil about a pivot axis of the hinge device 112. In this way, power may be wirelessly transmitted from the transmitter coil to the receiver coil, thereby realizing power transmission from the main body 110 of the washing machine 2 to the pivotal part 120 or washing machine door. In another embodiment, the first coil 111 and the second coil 121 may be configured to achieve signal transmission from the washing machine door to the main body 110 of the washing machine 2.