Abstract: A "Y" adapter for supplying power to a marine vessel from a dockside power center having two receptacles includes two three-pole plugs insertable into the receptacles, a third four-pole plug for connection to the wiring system of the vessel and a sensing and control unit for selectively switching paths between these plugs. All conductor lines are switchable to the third plug and between the input plugs by a voltage and phase sensing unit and contactor arrangement. Energization of one input plug while the other one is plugged into a receptacle is prevented and other dangerous voltage circumstances are also prevented.

Abstract: A variable speed motor controller for an AC motor, said controller including a DC to AC converter for providing adjustable frequency AC signals to vary the speed of said motor, and a sensing device and energy saving control for detecting the magnitude of the current signal being supplied to the motor and adjusting the AC voltage to the motor depending upon the magnitude of the current signal. The smaller the motor current being sensed, the smaller the voltage applied to the motor, thereby effecting a saving of energy. Energy is saved using this controller because when the lesser motor current indicates that it is driving less than full load, the input voltage applied to the motor is reduced thereby effecting a power saving.