Progress made in the development of electrical equipment to serve adequately the needs of motorcoach service is reviewed. Electrical loads on motorcoaches are comparatively high, including the usual head, tail and dash lamps, body-marking and destination lamps and buzzer systems. As more and more electrical energy is used, the source of supply and its control become relatively more important. Not only does the electric generating system have to meet the demands of battery charging, but it should be able to carry the connected load with no battery in the circuit. This means that not only is sufficient energy necessary, but the voltage must be regulated in such a manner that the battery can be charged without endangering the life of the lamps because of excessive voltage, and no flicker in the light from the lamps must be perceptible. All these results must be attained under conditions of variable load, variable speed and the changeable temperatures encountered in service.
Voltage regulation is the latest development in the electrical control of an automotive generating system and the author describes it, together with other methods. The 12-volt voltage-regulator employed to accomplish regulation is considered in detail, it being designed to furnish regulated voltage energy to battery and lighting circuits on motor vehicles; to maintain the voltage within the limits required for sufficient, steady and non-flickering light from connected lamps; to assure long lamp-life by preventing excess voltage; and to provide the tapering charge, beneficial to the battery, which results automatically from regulated-voltage charging. The outstanding advantages of voltage regulation are summarized.