Monitor device, ground fault protection circuit and techniques
AssigneeLittelfuse, Inc.
InventorsKristophor Jensen, Kip M. Larson, Cornelis Verhey
Life of this patent
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Abstract
A fault protection arrangement may include a neutral grounding resistor, the neutral grounding resistor comprising a ground end and a non-ground end. The fault protection arrangement may include a neutral grounding resistance monitor assembly, coupled to the neutral grounding resistor, where the neutral grounding resistance monitor assembly includes a sense circuit, coupled to the ground end of the neutral grounding resistor; and an injection signal generator, arranged to generate a frequency of 240 Hz or greater.
Claims16
A fault protection arrangement, comprising:
- a neutral grounding resistor, the neutral grounding resistor comprising a ground end and a non-ground end;
- and
- a neutral grounding resistance monitor assembly, coupled to the neutral grounding resistor and comprising:
- a sense circuit, coupled to the ground end of the neutral grounding resistor;
- an injection signal generator, arranged to generate a frequency of 240 Hz or greater, wherein the injection signal generator is coupled on a first side to the non-ground end of the neutral grounding resistor, and on a second side to the sense circuit;
- and
- an injection capacitor, coupled in electrical series between the injection signal generator and the non-ground end of the neutral grounding resistor.
A fault protection arrangement, comprising:
- a neutral grounding resistor, the neutral grounding resistor comprising a ground end and a non-ground end;
- and
- a neutral grounding resistance monitor assembly, coupled to the neutral grounding resistor and comprising:
- a sense circuit, coupled to the non-ground end of the neutral grounding resistor;
- and
- an injection signal generator, coupled to the ground end of the neutral grounding resistor and arranged to generate a frequency of 240 Hz or greater;
- and
- a sense resistor, arranged in electrically parallel fashion with the sense circuit, between the non-ground end of the neutral grounding resistor, and the injection signal generator.
A fault protection method, comprising:
- providing a neutral grounding resistor, having a ground end, coupled to ground, and a non-ground end;
- generating, by an injection signal generator coupled on a first side to the non-ground end of the neutral grounding resistor, an injection signal having an injection signal frequency, above 240 Hz;
- and
- sensing a resistance of the neutral grounding resistor using a sense circuit, electrically coupled between the ground end of the neutral grounding resistor and the injection signal generator;
- wherein an injection capacitor is arranged in electrical series between the injection signal generator and the non-ground end of the neutral grounding resistor, and wherein a sense resistor is arranged in electrical series between the ground end of the neutral grounding resistor and the sense circuit.
Dependencies are inferred from the claim text.