Abstract: An improved ferroresonant transformer for a ferroresonant power supply, such as may be used for charging storage batteries, is provided by placing damping means, such as a strip of non-magnetic metallic material in an air gap of such a transformer, thereby eliminating the need for a damping resistor in the circuit of the resonant winding of such a transformer, thereby decreasing the size, weight, and cooling requirements of such a transformer and power supply, and allowing a greater electrical energy efficiency to be obtained.

Abstract: An on-board quick charge circuit for an electric vehicle battery is incorporated in an electric vehicle having a solid state dc chopper motor speed controller which may be connected in either a propulsion mode or in a battery charge mode. With the aid of an external donor battery at the charge station, load leveling at the utility grid is maintained irrespective of the instantaneous current demands in the battery charging process. Energy transfer from the donor battery to the on-board propulsion battery is controlled by solid state switching apparatus. Each time the switching apparatus conducts, energy as transferred from the donor battery to the on-board propulsion battery, and energy is additionally transferred and stored in the dc reactor associated with the dc chopper circuit of the vehicle propulsion system. The energy stored in the dc reactor is expended into the on-board propulsion battery when the switching apparatus is turned off.