| 摘要 |
A switch for speed control of an electric motor driven vehicle employs a combination of resistance switching, field weakening and voltage switching. A mechanical switch assembly has a speed switch and a voltage switch that are interconnected so that the voltage switch provides 36 volts when the speed switch is in neutral and fifth speed position and provides 18 volts when the speed switch is in first through fourth speed positions. The speed switch has an operator controlled rotor arm that successively engages a neutral contact and five driving speed contacts so that varying resistance is inserted in circuit with the motor armature in the first two speed positions and no external resistance is employed in the third and fifth speed positions. The motor field comprises pairs of first and second oppositely disposed series wound coils with the pairs of coils all connected and energized in series in all but the fourth speed position. In the fourth speed position one pair of oppositely disposed field coils is completely disconnected while the other pair is energized to provide a higher speed at the lower voltage and a better transition between low and high voltage driving speeds.
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