Multi-speed motor system combining at least a one speed electric motor, series resistor and power switches

A multi-speed permanent magnet D.C. electric motor system comprising:

• at least one permanent magnet DC electric motor configured to operate at at least one speed,
• current limiting structure constructed and arranged to lower electrical input power to the motor so that a speed of the motor is reduced, when the motor is powered together with the current limiting structure, as compared to a speed of the motor powered absent the current limiting structure, and
• switching structure associated with the current limiting structure to selectively operate the motor at at least three discrete speeds, even though the motor is configured for at least one speed operation,
• wherein the motor is a one-speed motor having a single winding and the current limiting structure includes only a first resistor and a second resistor.

A multi-speed permanent magnet D.C. electric motor system comprising:

• permanent magnet DC electric motor including a first winding for operating the motor at one of the two different speeds and a second winding for operating the motor at the other of the two speeds that is lower than the one speed,
• a single resistor defining a current limiting device constructed and arranged to lower electrical input power to the motor so that a speed of the motor is reduced, when the motor is powered together with the current limiting device, as compared to a speed of the motor powered absent the current limiting device, and
• switching structure including a first switch, a second switch, and a third switch arranged in series, the second switch being in parallel with the current limiting device such that when the second switch is open, current flows through the current limiting device, the third switch being selectively associated with a first contact that is constructed and arranged to ensure that current is supplied to both the first and second windings, and a second contact constructed and arranged to ensure that current is supplied only to the first winding,
• the switches being associated with the current limiting device to selectively operate the motor at at least three discrete speeds, even though the motor is configured for two-speed operation.

A multi-speed permanent magnet D.C. electric motor system comprising:

• at least one permanent magnet DC electric motor configured to operate at at least one speed,
• means for lowering input power to the motor so that a speed of the motor is reduced, when the motor is powered together with the means for lowering, as compared to a speed of the motor powered absent the means for lowering, and
• means, associated with the means for lowering, for selectively operating the motor at at least three discrete speeds, even though the motor is configured for at least one-speed operation,
• wherein the means for lowering is only a single resistor in series with the motor.