Siemens Energy & Automation, Inc.

Jerry M Green

Mario Bilac

William E May

Charles Randall Dollar, Ii

William A King

Harold L Taylor

Von G Pardue

A portable circuit breaker tester ( ) for testing a current transformer ( ) of a circuit breaker ( ) having a first terminal ( ) on a first end of the transformer and a second terminal ( ) on a second end of the transformer has a test port ( ) configured to be coupled to the first ( ) and second terminals ( ) and a test circuit ( ) coupled to the test port ( ). The test circuit ( ) is configured to provide a test current through the test port ( ) to the first terminal ( ), to monitor the second terminal ( ) through the test port ( ), and to provide an output signal to an indicia ( ) based on whether the test current is received at the second terminal ( ). The test circuit ( ) is configured to perform first and second testing operations on the circuit breaker ( ) through the test port ( ). During the first testing operation the test circuit ( ) provides a test signal to a terminal ( ) coupled to the current transformer and during the second testing operation the test circuit ( ) provides power to the circuit breaker ( ).

Portable tester for electronic circuit breaker

An apparatus ( ) (FIG. ) for differentially sensing a ground fault in a power distribution circuit is configured to route a plurality of power signals, the power signals when summed resulting in a zero sum signal. The apparatus ( ) includes a circuit element (e.g., a resistor) ( ), first and second current transformers (CTs) ( ), and a routing circuit ( ). The first and second current transformers ( ) are configured to sense first and second power signals and to generate first and second sense signals representative of the first and second power signals, respectively. The routing circuit ( ) is configured to receive the first and second sense signals to provide a residual signal across the circuit element ( ).

Method and apparatus for differentially sensing ground fault and individual phases

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.

Power supply for ground fault circuit interrupter

An apparatus for monitoring alternating currents and providing a signal representative of the current. The signals are rectified by a modified full wave rectrifier to provide a power source, a positive signal associated with the positive range of the current, and a positive signal associated with the negative range of the current. The two positive signals serve to preserve the polarity information associated with the current being monitored. The apparatus also provides for combining the negative signals to produce other signals useable by a microprocessor and an analog logic circuit.

Ground fault current rectification and measuring circuit

Ground fault interrupting circuit breaker (10) includes a sensing coil (20) which is the secondary winding of a current transformer having a core (18) and includes a test coil (22) also wound about the core with load conductors passing through the core. A current sensing circuit (30) compares the output from the sensing coil to a reference voltage which is adjustable to set the sensitivity of the breaker. A test circuit (42) generates in the test coil a test current whch has its magnitude determined by the same reference voltage which determines the sensitivity of the breaker, thus causing the test current to automatically track the sensitivity of the breaker without separate adjustment.

Growing community of inventors

Tucker, GA, United States of America

Jerry M Green