Clothes dryer over-voltage control apparatus and method
First Claim
1. An over-voltage control device for a clothes dryer including an electrical heater coupled to an alternating current power supply, said device comprising, a switch device adapted to connect and disconnect the power supply from the heater;
- and a micro-controller coupled to said switch device, said switch device responsive to said micro-controller, said micro-controller configured to operate said switch to maintain an effective heater voltage below a predetermined threshold to avoid tripping of a circuit breaker.
3 Assignments
0 Petitions
Accused Products
Abstract
An over-voltage control device for a clothes dryer including an electrical heater coupled to an alternating current power supply is provided. The device includes a switch device adapted to connect and disconnect the power supply from the heater, and a micro-controller coupled to the switch device. The switch device is responsive to said micro-controller, and the micro-controller is configured to operate said switch to maintain an effective heater voltage below a predetermined threshold to avoid tripping of a circuit breaker.
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Citations
20 Claims
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1. An over-voltage control device for a clothes dryer including an electrical heater coupled to an alternating current power supply, said device comprising,
a switch device adapted to connect and disconnect the power supply from the heater; - and
a micro-controller coupled to said switch device, said switch device responsive to said micro-controller, said micro-controller configured to operate said switch to maintain an effective heater voltage below a predetermined threshold to avoid tripping of a circuit breaker. - View Dependent Claims (2, 3, 4, 5)
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6. An over-voltage control system for a clothes dryer including an electrical heater, said control system comprising:
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a switch device adapted to disconnect the heater from an alternating current power supply;
a voltage converter coupled to the heater; and
a micro-controller coupled to said voltage converter and operatively coupled to the heater, said micro-controller configured to compare a signal from the voltage converter to a predetermined threshold value, and when the reference voltage is greater than the threshold value to operate said switch device to maintain an effective voltage applied to the heater at a voltage level below a rated voltage of the heater. - View Dependent Claims (7, 8, 9, 10)
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11. A clothes dryer comprising:
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a cabinet;
a drum rotatably mounted within said cabinet;
a fan for circulating air within said drum;
an electrical heater for warming air circulated by said fan;
a switch device coupled between said heater and an alternating current power supply, and a controller coupled to said switch device and configured to operate said switch to achieve a step reduction in the power supply voltage to the heater through said switch device, said step reduction governed by the relationship where Vave is a heater rated voltage, N is a frequency of the input power supply, and t is a predetermined time period for over-voltage compensation. - View Dependent Claims (12, 13, 14, 15)
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16. A method for controlling an electrical heater of a clothes dryer in an over-voltage condition, the clothes dryer including a controller coupled to a switch device for regulating a power supply input to the heater through operation of the switch, said method comprising:
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comparing an effective heater voltage to a threshold heater voltage; and
when the effective heater voltage is greater than the threshold voltage, opening the switch device to disconnect the power supply from the heater, said opening of the switch device for a predetermined number of voltage cycles on a periodic basis. - View Dependent Claims (17, 18)
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19. A method for operating a clothes dryer to avoid tripping of a circuit breaker rated at a threshold voltage for an alternating current power supply, the dryer including an electrical heater, a voltage converter adapted for generating a DC voltage reference signal corresponding to the actual voltage across the heater, a switch device for regulating a power supply input to the heater through operation of the switch, and a controller coupled to the voltage converter and to the switch device, said method comprising:
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closing the switch device to energize the heater;
comparing the DC voltage reference signal to a voltage threshold that corresponds to a rated voltage of the heater minus an over-voltage compensation value;
when the DC voltage reference signal is greater than the voltage step differential, opening the switch device to disconnect the heater from the power supply and reduce an effective voltage applied to the heater through the switch device by one voltage step, the voltage step defined by the relationship where Vave is a heater rated voltage, N is a frequency of the input power supply, and t is a predetermined time period for over-voltage compensation;
closing the switch device for a remainder of time t to connect the power supply to the heater; and
repeating opening of the switch device to achieve step reduction of voltage cycles to the heater upon the occurrence of every t time period. - View Dependent Claims (20)
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Specification