Square D Company

Gary Michael Stumme

Steve M Meehleder

David Joseph Dunne

Ryan James Moffitt

Kevin John Malo

Richard Allen Studer, Ii

William Davison

Susan Jean Walker Colsch

A method and system to calibrate a motor circuit protection device is disclosed. An example method calibrates a signal chain of a circuit breaker. The signal chain includes a current transformer, a burden resistor, a stored energy circuit and a controller. The circuit breaker includes a memory coupled to the controller. A calibration instruction routine is written in a first location of the memory. A test current is injected in the circuit breaker signal chain. The test current peak of the test current in the circuit breaker signal chain is measured. Data indicative of the test current peak is stored in a second location of the memory. The test current peak data is read from the second location of the memory. The test current peak data is compared with nominal current data related to the signal chain remotely from the circuit breaker. A calibration factor is determined based on the comparison.

Method and system of calibrating sensing components in a circuit breaker system

A portable field tester for a circuit breaker having an electronic trip unit includes a ribbon cable having a connector plug for making connection to a restraint plug socket of the trip unit. The tester has a parallel connector in which the breaker rating plug may be inserted. A battery source is included and a battery fail LED is illuminated if the source voltage falls below a certain level. A voltage regulator and a plurality of voltage dividers develop reference test voltages for application to the breaker trip unit via the connectors and cable. Switches selectively disable a ground fault test circuit in the breaker during primary injection testing. A pair of resistors are connected via the cable and connectors for rapidly discharging the breaker memory circuits after each test.

Field test unit for circuit breaker

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Cedar Rapids, IA, United States of America

Gary Michael Stumme