A fault indicator for detecting the occurrence of a fault current in a monitored conductor and providing a light indication thereof includes a rotatably mounted indicator flag. The flag is positioned in either a reset indicating or a fault indicating state by a magnetic pole piece, which is magnetized in one magnetic direction or the other by momentary application of a current in one direction or the other to an actuator winding on the pole piece. A magnetically actuated reed switch in an auxili...

A checking and fault-indicating arrangement is provided for four or a larger even number of processors in a data processing system. During a first predetermined period, odd-numbered processors perform a processing operation and the input date applied to one of the odd-numbered processors is also applied to a particular one of the adjacent even-numbered processors and the output of the two processors is compared in a comparator which provides a significant output if one of the processors are faul...

A circuit for actuating a circuit breaker to disconnect a load from across conductors connecting the load across an input circuit which has one neutral side upon the occurrence of an imbalance in the currents flowing in the conductors. The circuit includes a differential transformer having a bifilar pair of windings wound on a toroidal core, the winding being connected in series with separate conductors of the input circuit. The permeability of the toroidal core of the transformer is quite low w...

A circuit for protecting a DC power source such as a DC generator or a battery from a ground fault condition between two points in a current path connected to the source. One point may be a terminal of the source and the other a load bus to which the source is connected by a feeder conductor. Sensing means such as a current transformer at each of the points senses changes in current flowing and provides a signal proportional thereto. The two sensing means are connected with their outputs in seri...

A conference arrangement is disclosed having a plurality of logical multiport bridges for conferencing customer stations. Equipment units common to the bridges can be selectively connected to a station controlling each bridge. Upon the detection of a faulty unit, the interaction between the controlling station and the bridge is halted while a new unit is substituted. Announcements prompt the controlling station to reactivate the transaction that was halted. If the controlling station is off the ...

A servo motor feedback fault detector that combines the motor drive voltage, the current flowing through the motor and the rotational speed of the motor and compares this combined signal with a dynamic threshold generated by combining a percentage tolerance of the motor current with a percentage tolerance of the motor rotational rate.

An apparatus for providing visual indications of vehicle faults including an indicator light array and improved means for selective spraying of vehicle members with a marking fluid.

A T-carrier digital test system which actively monitors each T-carrier wire pair on a time division multiplexing basis while either live communications or test signals are on the line, and determines from the monitored data whether an incipient or hard failure of the line exists. It achieves this result by utilization of interacting devices called Scanners and Scanner Controllers. Each Scanner is housed in a repeater case and is connected to and monitors the output of each regenerative repeater ...

Apparatus and method for detecting and locating insulation faults in lengths of electrical conductive cable and plexing those lengths of cable into multiplex cable in one operation, wherein the multiplex cable includes either a bare cable and a plurality of insulated cables stranded together or a plurality of insulated cables stranded together.

A microcomputer controlled circuit arrangement for sensing fire and burglar alarms in the presence of undesired fault conditions, such as opens or shorts, on monitored communication lines. The arrangement includes transistor-resistor sensing circuitry which is shared by a plurality of monitored communication lines, each of which comprises a first pair of conductors connected to a first contact of an alarm sensor and a second pair of conductors connected to a second alarm sensor contact. The sens...