A method of locating an intermittent electrical fault in an optical undersea transmission system, comprises measuring the time difference between two signals emanating from the fault along two different routes of the system. In one embodiment one of the signals is a voltage transient and the other signal is an optical error signal created in a repeater adjacent the fault as a result of surge protection in the repeater responding to the electrical fault, and in another embodiment both signals are...

A fault detector for detecting shoot-through conditions in series connected solid state rectifiers (326, 329) of a power inverter (314) is disclosed. A capacitor (311) discharges when a shoot-through occurs and the discharge current is detected by a current transformer (315). An SCR (317) is gated on by the detector to short circuit the DC bus (327, 328) and prevent damage to the solid state rectifiers (326, 329).

Apparatus for the detection of leakage current in a system includes a power supply and conductors from the supply for supplying power to a load connected to the system. There is an interrupter connected in the system and to a ground point such that a ground leakage current in the system has a closed circuit. Activation of the interrupter about every 12 seconds effectively generates a pulse interrupted ground fault signal. Such signal is detected by a magnetic sensor located relative to a multi-f...

A fault finder for locating faults along a high voltage electrical transmission line. Real time monitoring of background noise and improved filtering of input signals is used to identify the occurrence of a fault. A fault is detected at both a master and remote unit spaced along the line. A master clock synchronizes operation of a similar clock at the remote unit. Both units include modulator and demodulator circuits for transmission of clock signals and data. All data is received at the master ...

A cold forging machine comprises a fixed die 11 and a movable punch tool 13 reciprocable towards and away from the fixed die to act on a workpiece therein. The tool comprises a tubular punch 34 and extrusion pin 33 movable through the punch to form a bore in the workpiece. The die is provided with a tubular ejector 15 in which slides a carrier pin 16 to enter the bore of the formed workpiece to guide it during ejection. A fault detection system includes a switch 25,61 for detecting non-completio...

An automatically resettable fault indicator includes a rotatably-mounted target viewable from the exterior of the indicator for indicating circuit status. The target is positioned in a reset-indicating state by a reset circuit which periodically energizes a first winding to position a permanent magnet mounted for rotation with the target. Upon occurrence of a fault circuitry within the indicator energizes a second winding to reposition the target to a fault-indicating position. A delay circuit i...

A new type of immersible fault detector which includes a magnetic coupling link that can be coupled to a power line and a detector receives energy proportional to the load currents flowing in the power line and energizes a light source. A fiber-optics light waveguide or cable is connected to the detector so as to detect the light generated by the detector and has its opposite connected to an indicator which is remote from the detector and is electrically insulated therefrom so that the condition...

A fault tolerant/fault resilient computer system includes at least two compute elements connected to at least one controller. Each compute element has clocks that operate asynchronously to clocks of the other compute elements. The compute elements operate in a first mode in which the compute elements each execute a first stream of instructions in emulated clock lockstep, and in a second mode in which the compute elements each execute a second stream of instructions in instruction lockstep. Each ...

Apparatus for detecting and isolating the occurrence of faults in a digital electronic system so as to reduce the mean-time-to-repair. Associated with the logic circuitry to be monitored is a fault indicator which produces a fault signal when a malfunction occurs. Fault capture circuitry is arranged in a hierarchical manner and provides a group fault output signal when one of the fault indicators generates a fault signal. A programmable controller is provided which receives the group fault signa...

A high voltage fault interrupter including a vacuum interrupter having a fixed contact and a movable contact, a trip mechanism module connected to said movable contact, said trip mechanism module monitoring the power line for conditions which call for circuit interruption, a dielectric housing completely enclosing said interrupter and said trip mechanism module, the housing including a flexible dielectric interface, and an actuating and reset module connected to said trip mechanism module throug...