Power supply for ground fault circuit interrupter
First Claim
1. A ground fault circuit interrupter, for attachment to a load and detecting a ground fault condition associated with a load in an electrical distribution system, and for disconnecting the load from the system in response thereto, comprising:
- coupling circuit means connected to an electrical distribution system to provide a signal indicative of a ground fault imbalance in the system;
a ground fault detector circuit connected to receive a ground fault imbalance signal, and operative in response to a power signal having specified voltage and current levels, said ground fault triggering circuit providing a ground fault trigger signal when the imbalance exceeds a certain level indicative of a ground fault in a load in the system;
a regulated power supply circuit connected to the electrical distribution system for generating and supplying to said ground fault interruption circuit a power signal having the specified voltage level at a regulated constant current level; and
a power disconnector including circuit breaker contacts for disconnecting the load from the system in response to receipt of a ground fault trigger signal;
wherein the power supply circuit comprises a start up and storage portion, and a constant current supply portion; and
wherein the start up and storage portion comprises a transistor having its collector connected to receive a rectified pulse signal, its base connected to a voltage reference source and first capacitor, and its emitter connected to a storage capacitor, to provide a charging path to charge the storage capacitor with a regulated voltage.
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Accused Products
Abstract
A ground fault interruption circuit detects a ground condition associated with a load in an electrical distribution system and disconnects the load in response to a ground fault condition. The circuit includes a ground fault detector connected to receive a ground fault imbalance signal and operative in response to a power signal, having specified voltage and current levels, to provide a trigger signal to disconnect the load from the system when the imbalance exceeds a certain level. A regulated power supply circuit a substantially constant current and voltage signal to the detector to minimize excess power to the detector and heat loss. The power supply includes a start up and storage portion and a constant current supply portion.
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Citations
13 Claims
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1. A ground fault circuit interrupter, for attachment to a load and detecting a ground fault condition associated with a load in an electrical distribution system, and for disconnecting the load from the system in response thereto, comprising:
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coupling circuit means connected to an electrical distribution system to provide a signal indicative of a ground fault imbalance in the system; a ground fault detector circuit connected to receive a ground fault imbalance signal, and operative in response to a power signal having specified voltage and current levels, said ground fault triggering circuit providing a ground fault trigger signal when the imbalance exceeds a certain level indicative of a ground fault in a load in the system; a regulated power supply circuit connected to the electrical distribution system for generating and supplying to said ground fault interruption circuit a power signal having the specified voltage level at a regulated constant current level; and a power disconnector including circuit breaker contacts for disconnecting the load from the system in response to receipt of a ground fault trigger signal; wherein the power supply circuit comprises a start up and storage portion, and a constant current supply portion; and wherein the start up and storage portion comprises a transistor having its collector connected to receive a rectified pulse signal, its base connected to a voltage reference source and first capacitor, and its emitter connected to a storage capacitor, to provide a charging path to charge the storage capacitor with a regulated voltage. - View Dependent Claims (2)
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3. A ground fault circuit interrupter, for attachment to a load and detecting a ground fault condition associated with a load in an electrical distribution system, and for disconnecting the load from the system in response thereto, comprising:
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coupling circuit means connected to an electrical distribution system to provide a signal indicative of a ground fault imbalance in the system; a ground fault detector circuit connected to receive a ground fault imbalance signal, and operative in response to a power signal having specified voltage and current levels, said ground fault triggering circuit providing a ground fault trigger signal when the imbalance exceeds a certain level indicative of a ground fault in a load in the system; a regulated power supply circuit connected to the electrical distribution system for generating and supplying to said ground fault interruption circuit a power signal having the specified voltage level at a regulated constant current level; a power disconnector including circuit breaker contacts for disconnecting the load from the system in response to receipt of a ground fault trigger signal; and a Zener diode as a current reference source.
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4. A ground fault circuit interrupter, for attachment to a load and detecting a ground fault condition associated with a load in an electrical distribution system, and for disconnecting the load from the system in response thereto comprising:
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coupling circuit means connected to an electrical distribution system to provide a signal indicative of a ground fault imbalance in the system; a ground fault detector circuit connected to receive a ground fault imbalance signal, and operative in response to a power signal having specified voltage and current levels, said ground fault triggering circuit providing a ground fault trigger signal when the imbalance exceeds a certain level indicative of a ground fault in a load in the system; a regulated power supply circuit connected to the electrical distribution system for generating and supplying to said ground fault interruption circuit a power signal having the specified voltage level at a regulated constant current level; and a power disconnector including circuit breaker contacts for disconnecting the load from the system in response to receipt of a ground fault trigger signal; wherein the power supply circuit comprises a start up and storage portion, and a constant current supply portion; and wherein the start up and storage portion comprises a storage capacitor and means for providing a low impedance charging path for a current signal to said storage capacitor. - View Dependent Claims (5)
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6. A ground fault interruption circuit, for detecting a ground fault condition associated with a load in an electrical distribution system, and for disconnecting the load from the system in response thereto, comprising:
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coupling circuit means connected to an electrical distribution system to provide a signal indicative of a ground fault imbalance in the system; a ground fault detector circuit connected to receive a ground fault imbalance signal, and operative in response to a power signal having specified voltage and current levels, said ground fault triggering circuit providing a ground fault trigger signal when the imbalance exceeds a certain level indicative of a ground fault in a load in the system; a regulated power supply circuit connected to the electrical distribution system for generating and supplying to said ground fault interruption circuit a power signal having the specified voltage level at a regulated constant current level, said power supply circuit comprising; a start up and storage portion comprising a first transistor having its collector connected to receive a rectified pulse signal, its base connected to a voltage reference source and first capacitor, and its emitter connected to a storage capacitor, to provide a low impedance charging path to charge the storage capacitor to a regulated voltage; and a constant current supply portion comprising a resistor, a second transistor having its base emitter junction in parallel with the second transistor to provide a substantially constant current through the resistor and a regulated constant current to the detector circuit; and power disconnect means for disconnecting the load from the system in response to receipt of a ground fault trigger signal. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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Specification