Littelfuse, Inc.

Kristophor Ray Jensen

Kip McArthur Larson

Cornelis Verhey

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.

Monitor device, ground fault protection circuit and techniques

A fault protection arrangement. The fault protection arrangement may include a neutral grounding resistor including a first non-ground end, connected to a neutralizing point, and a second non-ground end. The fault protection arrangement may include a neutral grounding resistance monitor assembly, directly coupled to the second non-ground end of the neutral grounding resistor. The neutral grounding resistance monitor assembly may include comprising a signal source coupled to the neutralizing-point; a first current sense circuit coupled between the signal source and the neutralizing-point; a first voltage sense circuit coupled between the signal source and the neutralizing-point; a second current sense circuit, comprising a current sensor, coupled between the second non-ground end of the neutral grounding resistor and a protective earth connection.

Ground fault protection circuit and techniques

A floating two-terminal unipolar current limiting circuit arrangement implemented with enhancement mode devices and bipolar devices with a unique voltage-current operation curve. This operation curve makes this device particularly advantageous to instrumentation systems that are intended to experience large voltage transients and long-term exposure to voltages that would normally damage measurement equipment. The present current limiting device is designed to have a large impedance value prior to a 'turn-on' voltage, then quickly transitions to a low-impedance state. When the conducted current exceeds a setpoint or a high-voltage event occurs, the current limiting device further transitions to the 'cutoff' region, which transition resumes the initial high-impedance state. In one embodiment the threshold current may be set with internal components, while a further embodiment allows the current setpoint to be set by external components. The current limiting device designs according to the present embodiments allow for series scaling and parallel scaling.

Current limiting circuit arrangement

A neutral grounding resistor fault protection arrangement. The fault protection arrangement may include a neutral grounding resistor, the neutral grounding resistor comprising a ground end and a non-ground end; a sense circuit, coupled to the non-ground end of the neutral grounding resistor; and a neutral grounding monitor, coupled to the non-ground end of the neutral grounding resistor, the neutral grounding monitor comprising an injection signal generator, the injection signal generator arranged to generate a frequency of 240 Hz or greater.

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Chicago, IL, United States of America

Kristophor Ray Jensen