Electric motor and transformer load sensing technique
First Claim
1. Apparatus for monitoring the current flow in a high voltage electrical load, such as a motor or transformer, comprising,a high voltage section including a Faraday rotator optical sensor means for generating an optical signal indicative of the current flow in a high voltage electrical load,a low voltage section including a signal processing circuit means,first optical coupling means connected between said high voltage section and said low voltage section to optically transmit said optical signal from said Faraday rotator optical sensor means to said signal processing circuit means, said optical coupling means providing electrical isolation and noise immunity for said low voltage section,said signal processing circuit means including first circuit means for converting said optical signal to an electrical signal manifesting the positive and negative half cycles of the current flow in said high voltage electrical load, second circuit means for comparing the positive half cycles of said electrical signal to a predetermined threshold, and the negative half cycles of said electrical signal to a second predetermined threshold and generating electrical overload output signals in the event the half cycles of said electrical signal exceed said respective thresholds, said third circuit means for converting said electrical overload output signal into an optical overload output signal.
0 Assignments
0 Petitions
Accused Products
Abstract
A Faraday rotator optical sensor in combination with optical fiber transmission means is employed to monitor overload current conditions in a high voltage electrical load and transmit this information to a low voltage signal processing circuit while providing desired isolation between the high voltage load and the low voltage signal processing circuit.
-
Citations
7 Claims
-
1. Apparatus for monitoring the current flow in a high voltage electrical load, such as a motor or transformer, comprising,
a high voltage section including a Faraday rotator optical sensor means for generating an optical signal indicative of the current flow in a high voltage electrical load, a low voltage section including a signal processing circuit means, first optical coupling means connected between said high voltage section and said low voltage section to optically transmit said optical signal from said Faraday rotator optical sensor means to said signal processing circuit means, said optical coupling means providing electrical isolation and noise immunity for said low voltage section, said signal processing circuit means including first circuit means for converting said optical signal to an electrical signal manifesting the positive and negative half cycles of the current flow in said high voltage electrical load, second circuit means for comparing the positive half cycles of said electrical signal to a predetermined threshold, and the negative half cycles of said electrical signal to a second predetermined threshold and generating electrical overload output signals in the event the half cycles of said electrical signal exceed said respective thresholds, said third circuit means for converting said electrical overload output signal into an optical overload output signal.
Specification