Stepped voltage power supply with equalized discharge of battery cells

A stepped voltage electric power supply for a vehicle mounted electric motor, comprising, in combination:

• a plurality of regularly spaced contact pairs;
• a first commutating member having a plurality of regularly spaced contact members effective to connect the contacts of each pair but one, the commutating member being movable sequentially through a plurality of positions, each position providing a different unconnected contact pair, one of the contact members adjacent the unconnected contact pair providing a first output terminal;
• a plurality of electric power cells, each cell being connected in a consistent polarity between the adjacent contacts of adjacent contact pairs and each contact pair being connected to its adjacent contact pairs on either side by such cells, whereby the contact members of the first commutating member are effective to connect the cells in series;
• a second commutating member having a single contact member effective to connect the contacts of one of said pairs and provide a second output terminal, the second commutating member being movable sequentially through a plurality of positions, each position providing a different connected contact pair;
• actuator means movable sequentially through a plurality of positions in a first, output voltage increasing direction and a second, opposite, output voltage decreasing direction;
• drive means connecting the actuator to the first and second cummutating members, the drive means including unidirectional clutch means effective to move the first commutating member in one direction to increase the number of cells connected across the output terminals with movement of the actuator means in its first direction and to move the second commutating member in the same one direction to decrease the number of cells connected across the output terminals with movement of the actuator means in its second direction, whereby the specific cells connected across the output terminals are changed with movement of the actuator means in the first and second directions to equalize the discharge of the cells with use.