Other

Schneider Electric Usa, Inc.

Square D Company

Richard Allen Studer, Ii

Steve M Meehleder

Ryan James Moffitt

Kevin John Malo

William Davison

David Joseph Dunne

Susan Jean Walker Colsch

Gary Michael Stumme

A circuit breaker system for providing thermal protection to a conductor conducting current from a power source to a load. While the power source is connected to the load, a microcontroller is powered by the current passing through the conductor to thermally model the temperature of the conductor. If the microcontroller determines that the temperature of the conductor has risen to an undesirable or unsafe level, the circuit breaker disconnects the power source from the load and the current no longer passes through the conductor. With no current passing through the conductor, the microcontroller no longer receives power from the conductor. Instead, the microcontroller continues to model the temperature of the conductor as the conductor cools to an ambient temperature by receiving power from an energy storage device. Accordingly, the microcontroller continuously models the temperature of the conductor until the temperature of the conductor cools to the ambient temperature.

Thermal memory in a fault powered system

A thermal sensing system for providing thermal protection to an electronic circuit breaker that does not require any additional components. The layout of the conductive traces on the printed circuit board are dimensioned and configured so that the ratio of primary current to primary conductor thermal mass heating is correlated with the ratio of secondary current to secondary thermal mass heating. A voltage at a semiconductor junction in the rectifier behind the secondary transformer is measured, and a temperature or heat is calculated based on the voltage. Because this temperature or heat calculation is correlated with the temperature or heat of the primary conductor, a trip routine can be added based on the measured voltage for thermal protection of the primary conductors. A thermal history of the 'primary thermal mass' is also provided for robust thermal protection of the circuit breaker load and primary conductors.

Secondary thermal sensor for primary conductors

In a circuit breaker, a current transformer for fault powering trip unit electronics and sensing low currents and high currents includes a core with solid laminations and gapped laminations to sense a wide range of currents from locked-rotor currents to high, instantaneous short-circuit currents in a single current transformer. The current transformer can also fault power trip unit electronics without requiring an additional current transformer. The operating range of the circuit breaker is significantly enhanced compared to existing breakers that can sense only a limited range of current levels.

Circuit breaker-like apparatus with combination current transformer

A time-synchronized trip implementation for a motor circuit protector (MCP) having a reconfigurable microcontroller. The microcontroller causes a power supply to, be charged for an initial time period during a charging mode. An onboard comparator is configured for a predetermined self-protection level of the MCP, and fault currents that exceed the comparator's threshold will directly drive a solenoid to trip the MCP. The microcontroller reconfigures the comparator's threshold to both measure and charge the power supply toward a stored energy trip voltage, which will charge quickly when high fault currents are present. As a result, self-protection is not compromised. After the trip voltage is reached, the microcontroller reconfigures the onboard comparator's threshold for self-protection trip levels. When a trip event occurs in this mode, stored energy trip activation occurs. The MCP includes user-selectable trip settings, and the microcontroller reconfigures the comparator threshold levels for user-selectable self-protection levels.

Method and system for time synchronized trip algorithms for breaker self protection

A method and system to detect currents in the saturation region of a current transformer for a circuit breaker is disclosed. An example method is sensing a fault condition with a current transformer in a circuit breaker. The characteristic curve of the current transformer in a saturation mode is determined based on peak current. A current is received on the transformer. A secondary current is output from the transformer. It is determined whether the secondary current is indicative of a fault current in the saturation mode of the transformer. The breaker is tripped if the secondary current is indicative of a fault current.

Method and system of current transformer output magnitude compensation in a circuit breaker system

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 motor circuit protector that trips in accordance with an instantaneous trip curve that is split into three protection regions, a self-protection region, an in-rush avoidance region, and a locked-rotor avoidance region. Software modules for detecting whether primary current exceeds each region are run in parallel or simultaneously, providing redundant instantaneous trip detection, and these redundant protection regions remain active throughout the startup and steady-state modes of operation of the motor circuit protector. This redundancy provides improved time current trip performance for a wide variety of short circuit conditions and improved system safety properties are realized. The current threshold for the self-protection region can be adjusted toward the in-rush avoidance region once steady-state operation is achieved. In startup mode, only the self-protection region may be detected, but can remain active during steady-state mode.

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Wesley, IA, United States of America

Richard Allen Studer, Ii