Apparatus and method for starting and controlling a motor
First Claim
1. An apparatus for starting a motor having a starting load and for controlling the motor during a period of normal operation, the apparatus comprising:
- a timing circuit for initiating a start-up period having a predetermined duration upon detecting an initial application of power, the timing circuit having an output for providing an indication of the start-up period;
a main control circuit having an input coupled to the output of the timing circuit for receiving the indication of the start-up period, the control circuit for applying variable magnitudes of power to a main winding of the motor, the power having a fixed, substantially maximum magnitude during the start-up period and an adjustable magnitude during the period of normal operation, the period of normal operation generally following the start-up period, the duration of the start-up period being at least as long as necessary for the motor to overcome the starting load thereon; and
a start-up control circuit having an input coupled to the output of the timing circuit for receiving the indication of the start-up period, the start-up control circuit for applying power to a start-up winding of the motor during the start-up period, the power applied to the start-up winding during the start-up period being in addition to the power applied to the main winding during the start-up period to overcome the starting load on the motor.
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Accused Products
Abstract
An apparatus and method for starting and controlling a motor comprises a timing circuit and a main control circuit. The timing circuit initiates a start-up period upon detecting power and provides an indication of the start-up period. The main control circuit receives the indication of the start-up period and applies variable magnitudes of power to a main winding of the motor. During the start-up period, the power applied to the main winding has a fixed, substantially maximum magnitude. During a period of normal operation following, the power applied to the main winding has a user-adjustable magnitude. The start-up period duration is as long as necessary for the motor to overcome a starting load thereon. Preferably, the timing circuit has a timer measuring the start-up period and a main relay signaling the start-up period to the main control circuit. Preferably, the apparatus also has a start-up relay and a start-up control circuit applying power to a start-up winding of the motor in addition to the power applied by the main control circuit to the main winding during the start-up period.
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Citations
23 Claims
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1. An apparatus for starting a motor having a starting load and for controlling the motor during a period of normal operation, the apparatus comprising:
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a timing circuit for initiating a start-up period having a predetermined duration upon detecting an initial application of power, the timing circuit having an output for providing an indication of the start-up period; a main control circuit having an input coupled to the output of the timing circuit for receiving the indication of the start-up period, the control circuit for applying variable magnitudes of power to a main winding of the motor, the power having a fixed, substantially maximum magnitude during the start-up period and an adjustable magnitude during the period of normal operation, the period of normal operation generally following the start-up period, the duration of the start-up period being at least as long as necessary for the motor to overcome the starting load thereon; and a start-up control circuit having an input coupled to the output of the timing circuit for receiving the indication of the start-up period, the start-up control circuit for applying power to a start-up winding of the motor during the start-up period, the power applied to the start-up winding during the start-up period being in addition to the power applied to the main winding during the start-up period to overcome the starting load on the motor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A process for starting a motor having a starting load and for controlling the motor during a period of normal operation, the process comprising the steps of:
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initiating a start-up period having a predetermined duration upon detecting an initial application of power to the motor; providing for variable magnitudes of power to be selectively applied to the motor; applying a fixed, substantially maximum magnitude of power to a main winding of the motor during the start-up period; applying a fixed, substantially maximum magnitude of power to a start-up winding of the motor during the start-up period; applying at least one of the variable magnitudes of power to the main winding of the motor during the period of normal operation, the period of normal operation generally following the start-up period, the duration of the start-up period being at least as long as necessary for the motor to overcome the starting load thereon; applying substantially no power to the start-up winding of the motor during the period of normal operation; and measuring the duration Of the start-up period with a resistive-capacitive circuit and a switching circuit, the resistive-capacitive circuit having a resistor and a capacitor, the resistive-capacitive circuit also having an RC time constant, the switching circuit coupled to the resistive-capacitive circuit and having an open state and a closed state, the measuring step comprising the steps of; charging the capacitor through the resistor according to the RC time constant upon the initial application of power; and shifting the switching circuit from one of the open state and the closed state to the other of the open state and the closed state when the charge on the capacitor crosses from a first predetermined range to a second predetermined range. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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Specification