A relay with two current paths thermally connected in parallel is particularly fail-safe. In case of a failure of one main contact, the additional load current is led via the remaining functioning main contact. The failed main contact as well as the thermal connection between the two main contacts then serve as heat sinks, whereby the relay can continue to operate.

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.

A method for diagnosing an operating state, i.e., wear, of a contactor which includes a processing unit directing voltage control means; an, actuating coil; means for measuring an electric characteristic of the actuating coil; and a diode in parallel with the coil and the measuring means; the method including creating, for a specific contactor design, a plurality of variation curves of an electric characteristic of the coils of such contactors, over a drop-out period, by testing said contactors by sending a drop-out order fixing a drop-out voltage across the coil; after the drop-out order, repeatedly measuring the electric characteristic of the coil during a drop-out period; later sending a diagnostic drop-out order fixing the same drop-out voltage across the terminals of an actuating coil of a subject contactor being diagnosed; then measuring the same electric characteristic of the subject coil during a drop-out period; identifying a measured value of that characteristic of the subject coil, then comparing that measured value with the variation curves of the plurality of contactors of the same design, thereby diagnosing a state of wear of the subject contactor.

The present invention is directed to an electrical wiring device that includes an automatic test circuit configured to commence an automatic test at a predetermined time such that a test current propagates on a test conductor. The sensor assembly provides a sensor test output responsive to the test current only if both the differential transformer and the grounded neutral transformer are operative. A fault detector circuit is configured to generate a test detection signal in response to the sensor test output only if the fault detector circuit is operable and the at least one power supply is substantially charged. A device integrity evaluation circuit includes a timer that effects a tripped state when a time measurement exceeds a threshold, the test detection signal resetting the time measurement when properly wired before the time measurement exceeds the predetermined threshold but does not reset the time measurement when miswired.

A monitoring device for switching systems including a contact assembly having at least a movable contact and a kinematic chain for actuating said movable contact and opening/closing the contact assembly. The monitoring device includes: an accelerometer adapted to be positioned on a moving part of the switching system and capable of determining acceleration data of the moving part; a control unit including: a first processing unit adapted to receive acceleration data measured by the accelerometer and calculate timing instants of predetermined events and motion parameters related to the switching system; a second processing unit adapted to receive the timing instants of predetermined events and the motion parameters and to use at least one timing instant and at least one motion parameter to calculate electro/mechanical parameters of the switching system.

A switch includes a switch housing having a receiving space, a conductive fixed contact element and a conductive active contact element which are provided in the receiving space and being electrically connected to two terminals of the switch respectively, an actuating member reciprocating movable in a predetermined actuating direction between a rest position and an actuated position, and a conductive spring contact element movable with the actuating element. The spring contact element is in constant contact with the fixed contact element and switched between a state of being in contact with a conductive contact surface of the active contact element and a state of being disconnecting with the conductive contact surface of the active contact element. The actuating element is moved back from the actuated position to the rest position due to spring force of the spring contact element.

A system and method are disclosed for monitoring at least one relay contact. The system may include an emitter adapted for communication with a relay contact and configured to emit a signal, and a receiver adapted for communication with the relay contact and configured to detect a signal emitted by the emitter. The system may further include a controller adapted for communication with the emitter and receiver, and configured to determine an open or closed state of the relay contact. The controller may control the emitter to emit a signal, may determine a closed state of the relay contact if the receiver detects the signal, and may determine an open state of the relay contact if the receiver fails to detect the signal.

A closed and open contact method to predict a usable life of vacuum interrupters in the field can include using computer instructions in the data storage to instruct the processor to position a calculated amp or calculated pressure on an ionic or current versus pressure calibration curve for the installed vacuum interrupter and identify trend data from a library of trend data corresponding to the installed vacuum interrupter and to the calculated pressure or calculated amp of the installed vacuum interrupter; thereby determining the anticipated life expectancy.

An apparatus for use with a dynamoelectric machine includes a main body configured for attachment to a brush holder. A proximity sensor is on the main body, and the proximity sensor is configured for detecting the presence of a brush located at least partially inside the brush holder. The apparatus receives power from a battery located inside the apparatus, and transmits a wireless signal. The wireless signal is transformable into an indication of a remaining life of the brush. The apparatus is configured to be fully operational when the dynamoelectric machine is neither energized nor in operation, as the apparatus receives power from the battery.

An electrical circuit includes a contact with a pair of switchable electrodes, the contact configured to cycle through make and break transitions while conducting current. The electrical circuit further includes an arc suppressor, at least one sensor, and a controller circuit. The arc suppressor is coupled across the pair of switchable electrodes and is to extinguish an arc formed across the pair of switchable electrodes during the make and break transitions of the contact. The at least one sensor is coupled to the pair of switchable electrodes and is configured to generate sensor data. The controller circuit includes a plurality of registers and is configured to detect a fault condition associated with the contact based on the sensor data. The controller circuit further sequences contact opening of the contact based on the detected fault condition and a timing value stored in at least one register of the plurality of registers.