Speed reduction switch
First Claim
1. A speed reduction switch for a variable speed electric motor, the motor including at least a first set of windings for operating the motor at a first speed, and a second set of windings for operating the motor at a second speed that is lower than the first speed, said speed reduction switch comprising:
- a speed selector switch comprising at least a first throw and a second throw, said first throw operationally connected to the motor to energize the first set of windings and said second throw operationally connected to the motor to energize the second set of windings; and
a time delay element electrically connected in series with said second throw, said delay element delaying electrical connection between the motor and said second throw for de-energizing the motor for a predetermined period of time.
15 Assignments
0 Petitions
Accused Products
Abstract
A speed reduction switch for a multiple speed induction motor includes a speed selector switch and a delay element. As the motor is switched from a high speed to a lower speed, the delay element temporarily prevents electrical connection of a motor auxiliary winding for low speed operation. The motor is therefore de-energized and slows down. After a preselected delay, the delay element connects the motor auxiliary winding when the motor is at a lower speed so that little magnetic braking of the motor occurs, and the motor smoothly transitions from a higher speed to a lower speed.
71 Citations
17 Claims
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1. A speed reduction switch for a variable speed electric motor, the motor including at least a first set of windings for operating the motor at a first speed, and a second set of windings for operating the motor at a second speed that is lower than the first speed, said speed reduction switch comprising:
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a speed selector switch comprising at least a first throw and a second throw, said first throw operationally connected to the motor to energize the first set of windings and said second throw operationally connected to the motor to energize the second set of windings; and a time delay element electrically connected in series with said second throw, said delay element delaying electrical connection between the motor and said second throw for de-energizing the motor for a predetermined period of time. - View Dependent Claims (2, 3, 4, 5, 6, 8, 9, 10)
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7. A speed reduction switch for a variable speed electric motor, the motor including at least a first set of windings for operating the motor at a first speed, and a second set of windings for operating the motor at a second speed that is lower than the first speed, said speed reduction switch comprising:
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a speed selector switch comprising at least a first throw and a second throw, said first throw operationally connected to the motor to energize the first set of windings and said second throw operationally connected to the motor to energize the second set of windings; and a delay element electrically connected in series with said second throw, said delay element delaying electrical connection between the motor and said second throw, comprising a voltage relay switch connected across the first set of windings.
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11. A method for switching a motor from a first, high speed to a second, lower speed to reduce switch down noise in a multiple speed electric motor, the motor including at least a first set of windings for operating the motor at the first speed, a second set of windings for operating the motor at the second speed, and a speed selector switch operatively connected to the first set of windings and to the second set of windings, respectively, for high speed operation and low speed operation of the motor, said method comprising the steps of:
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preventing instantaneous connection of the second set of windings when the speed selector switch is switched from the first speed to the second speed; allowing the motor to reduce speed for a predetermined period of time; and connecting the second set of windings for low speed operation after the motor has a reduced speed. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification