Littelfuse, Inc.

Littlefuse, Inc.

Geoffrey J Baker

Michael Vangool

Michael P Vangool

A device for monitoring a neutral grounding resistor (NGR), including first and second NGRs electrically connected in parallel, a rectifier circuit electrically connected in series with the second NGR and a voltage source and a logic resistor electrically connected in series with the second NGR. A logic circuit measures current passing through the logic resistor and determines the resistance of the first NGR based on the measured current and the resistance of the second NGR. As such, a failed-open or failed-short condition of the first NGR may be identified based at least in part on the determined resistance of the first NGR.

Neutral grounding resistor monitor

A method for processing output from a current transformer comprising deriving signal data from the output; converting the signal data from analog to digital format; removing a carrier signal from the signal data; squaring the signal data; and performing a recursive RMS algorithm on the signal data.

AC/DC current transformer

A single-coil, toroid-type current transformer circuit for detecting both AC and DC current. The current transformer circuit may include a current transformer and an oscillator electrically connected to the current transformer. The current transformer circuit may further include an open and short CT detection circuit electrically connected to the oscillator for facilitating determination of the connection and stability state of the current transformer. A processor may be electrically connected to an output of the open and short CT detection circuit for performing a series of operations on signal data generated by the open and short CT detection circuit and manipulating the operation of an electrical power system accordingly.

Growing community of inventors

Martensville, Canada

Geoffrey J Baker