Switching circuit providing adjustable capacitive series voltage dropping circuit with a fractional horsepower motor
First Claim
1. For use in combination with a fractional horsepower alternating current motor connected between hot and neutral wires to impose a series impedance reducing the voltage applied to the motor, a motor control system which comprises:
- (a) at least two independent parallel capacitors connected in series with a motor and connected in series with the hot wire for conducting alternating current power to the motor;
(b) first and second switching devices, each thereof being connected in series with one of said capacitors, wherein said switching devices conduct alternating current flowing between the hot and neutral wires and are controllably switched between off and on states to thereby control alternating current flow through the respectively connected capacitors; and
(c) control means connected to said switching devices for providing control signals to said switching devices to selectively switch said switching devices to the on state and the off state.
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Accused Products
Abstract
A control circuit for a fractional horsepower fan motor connected between hot and neutral wires in and AC circuit is shown. The control circuit includes two or more duplicate branches. Each branch is serially connected, and each branch includes a triac, series resistor and series capacitor. The triac has a gate terminal which is connected to an optical coupling circuit for isolation and responds to a control signal from a low voltage small current source. In an alternative embodiment, a single triac and optical coupling circuit can be used with different capacitors being switched in or out of the circuit.
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Citations
15 Claims
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1. For use in combination with a fractional horsepower alternating current motor connected between hot and neutral wires to impose a series impedance reducing the voltage applied to the motor, a motor control system which comprises:
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(a) at least two independent parallel capacitors connected in series with a motor and connected in series with the hot wire for conducting alternating current power to the motor; (b) first and second switching devices, each thereof being connected in series with one of said capacitors, wherein said switching devices conduct alternating current flowing between the hot and neutral wires and are controllably switched between off and on states to thereby control alternating current flow through the respectively connected capacitors; and (c) control means connected to said switching devices for providing control signals to said switching devices to selectively switch said switching devices to the on state and the off state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An apparatus for varying impedance to a small alternating current motor, such as a fan motor, to vary speed of the small motor when the small motor is connected to a source of alternating current power comprising:
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first switching means for connecting said source of power therethrough to said small motor; second switching means for connecting between at least two different paths, said second switching means being connected between said small motor and said source of power; first capacitor means in at least one of said different paths for increasing impedance therethrough to decrease the speed of said small motor when said second switching means selects the path including the first capacitor means; and control means operatively connected to said first switching means for providing a control signal to operate said first switching means. - View Dependent Claims (15)
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Specification