Magnetoresistive sensors are used to measure a load current of a switch. In some implementations, additionally a further current sensor may be used. In other implementations, more than one magnetoresistive sensor may be provided.

A contact measurement system for measuring a parameter of a contact of a switchgear includes: a first device for measuring an electrical resistance of the contact and mapping the electrical resistance spatially and/or dynamically; a second device for measuring an axial force of the contact and to map the axial force spatially and/or dynamically as a measured axial force; and a third device for measuring a position of the contact. The contact measurement system determines a position-depending force characteristic based on the measured axial force of the contact and the position of the contact. The contact measurement system determines a status of the contact based on a combination of the position-depending force characteristic with the electrical resistance of the contact.

A contact arrangement includes a first electrical contact, a second electrical contact and a measuring device for determining a contacting state between the first and second contacts. In a first contacting state the first and second contacts are electrically isolated from one another, and in a second contacting state the first and second contacts are electrically connected to one another. The measuring device includes an acoustic signal transmitter for transmitting an acoustic signal into the first contact, and a signal receiver connected to the second contact in a sound-conducting manner.

An electromagnetic testing assembly to predict a usable life of an installed vacuum interrupter in the field, which can include an electromagnetic testing device connected to a flexible magnetic field coil to generate a potential in a vacuum interrupter in an installation, magnetically monitor ion flow across one or more gaps in the vacuum interrupter, and apply trend data, tube chart information, and an algorithm to predict the usable life.

An electrical switching device including an input connection land, an output connection land, and a connection member that is capable of switching between a closed position allowing an electric current to flow between the input and output connection lands and an open position preventing the flow of the current between the input and output connection lands. The electrical switching device includes an accelerometer that is capable of measuring a component of an acceleration of the switching device when switching the connection member between the closed and open positions and a control configured to estimate, on the basis of an acceleration measurement signal delivered by the accelerometer, a duration of switching of the connection member between the closed and open positions, and to determine wear on the switching device on the basis of the estimated switching duration.

A circuit breaker characteristic monitoring device monitors the operation of a circuit breaker to estimate the amount of consumption of a movable contact and fixed contacts included in the circuit breaker. The device includes an operating time measurement unit to measure at least one of closing time, which is the time required for the circuit breaker to be closed after starting a closing operation, and opening time, which is the time required for the circuit breaker to be open after starting an opening operation, and a contact consumption amount estimation unit to estimate the amount of consumption of the movable contact and the fixed contacts on the basis of the result of measurement performed by the operating time measurement unit and travel speed of the movable contact during the closing operation or the opening operation for which the measurement result is obtained.

A resistor assembly can include a resistor having a first end and a second end, and a conductive member, where the conductive member is coupled to the first end of the resistor. The resistor assembly can also include a shield cup and a housing, where the housing includes at least one housing wall having at least one aperture, and where the housing encloses at least a portion of the resistor and at least a portion of the shield cup. A volume of space between the at least one housing wall of the housing and the resistor can be substantially filled with an insulating material and at least the outside of the housing is substantially covered with the insulating material.

The embodiments described herein provide systems and methods for determining the health status of a sensed switch. In general, the embodiments described herein determine a measure of a health status of the sensed switch by comparing a voltage on the sensed switch, ascertaining a first comparator state under one test condition and ascertaining a second comparator state under a second test condition. The first comparator state and the second comparator state are and then compared to determine the measure of the health status of the sensed switch.

A method for determining the operating status of a MV switching device (1), which comprises one or more electric poles, each comprising a movable contact and a fixed, contact adapted to be coupled or uncoupled during the switching operations of said switching device, and an electromagnetic actuator comprising a magnetic core, a test coil wound around said magnetic core and a movable plunger operatively coupled to the movable contact of each electric pole. The method comprises: providing a test signal (ST) to said test coil for an observation period of time (T.sub.O), said test signal having a waveform adapted to excite said magnetic core; obtaining measuring data (V.sub.M, I.sub.M) indicative of the voltage at the terminals of said test coil and of the current circulating along said test coil during said observation period of time; calculating observation data (R.sub.N, I.sub.M) indicative of the electric behaviour of said test coil at the end of said observation period of time on the base of said measuring data; selecting at least a transformation function (F.sub.1, F.sub.2) indicative of the electromagnetic behaviour of said electromagnetic actuator; and calculating first estimation data (P, T) indicative of the operating status of said electromagnetic actuator on the base of said observation data (R.sub.N, L.sub.N) by using said transformation function, said first estimation data comprising, a first estimation value (P) indicative of the position of the movable plunger of said electromagnetic actuator.

A pivot supporting structure for a circuit breaker and a circuit breaker. The pivot supporting structure comprises: a supporting body having a supporting hole for receiving and pivotally supporting a pivot pin connected to an actuating mechanism of the circuit breaker, wherein at least one strain gauge are mounted to the supporting body for sensing the force acting on the pivot supporting structure by the actuating mechanism. This pivot supporting structure can accurately sense the characteristic force applied, such that the contact force and mechanical characteristics of the circuit breaker can be on-line monitored.