Trip signal verifying method and apparatus
AssigneeGeneral Electric Company
InventorsCraig B. Williams, Michael S. Tignor, Michael B. Bradley
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Abstract
A verifying trip unit includes a microcontroller providing a plurality of input signals to a logic device for controlling a trip unit actuator. The logic device produces an output signal for controlling a trip unit actuator. In response to the plurality of input signals, the logic device provides an output signal indicative of a function performed on the signals for opening the circuit breaker contacts in an overcurrent condition.
Claims20
A trip unit comprising:
- a sensor for sensing a condition of a circuit providing electricity to a load;
- a signal converter for converting signals generated by said sensor into a digital value indicative of said condition;
- a microcontroller configured to process said digital value;
- if an overcurrent condition is detected by said microcontroller, said microcontroller generates a first signal and a second signal in response to said overcurrent condition;
- and
- a logic device configured to process said first signal and said second signal and generate a trip signal if said first signal and said second signal are of different logic levels.
A circuit breaker comprising:
- a set of contacts for making and breaking an electrical connection between an electrical load and an electrical power supply;
- a trip unit operably connected to said contacts, said trip unit including
- a sensor for sensing a condition of a circuit providing electricity to said load;
- to a signal converter for converting signals generated by said sensor into a digital value indicative of said condition;
- a microcontroller for processing said digital value;
- if an overcurrent condition is detected by said microcontroller, said microcontroller generates a first signal and a second signal in response to said overcurrent condition;
- and
- a logic device configured to process said first signal arid said second signal and generate a trip signal if said first signal and said second signal are of different logic levels.
A method of minimizing nuisance tripping in a circuit breaker having a trip unit, the method comprising;
- detecting an overcurrent condition in a circuit providing electricity to a load;
- if an overcurrent condition is detected, generating a first signal having a first digital value and a second signal having a different second digital value in response to said overcurrent condition;
- and
- generating a trip signal if said first digital value and said second digital value are of different logic levels.
Dependencies are inferred from the claim text.