A fault tolerant multiplier which utilizes a plurality of full adder rows has the ability to permanently deselect a row when a fault is detected in its initial testing. An extra row is provided to allow this deselection and transfer gates are provided between each row to shift the sum and carry logic on to the next row at the point of the deselected row and all rows therebeyond.

Faults in the operation of a multi-phase A.C. generator are detected by monitoring the phase difference between two line-to-line voltage of the generator and comparing this phase difference with a predetermined value or range of values to indicate a fault.

A multi-stage, alternate routing switching network is enhanced with a switch architecture that is able to detect and mask all single faults. The switch employs a controller that develops dual rail control signals. In one embodiment, the controller is made up of two controllers that receive the same inputs but generate complementary outputs. The complementary outputs form the dual rail signals that control the multiplexers that are interposed between the inputs and the outputs of the switch. The ...

An integrated circuit having boundary-scan facilities in accordance with IEEE Standard 1149.1, has its boundary scan chain configured to permit fault insertion testing of diagnostic and maintenance software. Each Scan cell includes storage devices for storing a pair of bits of a binary vector shifted into the boundary scan chain. One bit comprises faulty data and the other bit serves to control application of the faulty data by the scan cell. A system incorporating such integrated circuits inclu...

A fault diagnosis expert system for locating and eliminating sources of a machine trouble. The system comprises a storage part for storing an expert knowledge constructed in a hierarchical search tree structure in which cause-to-effect links connecting high-level effect events to low-level cause events are pre-defined and all possible low-level cause events are pre-enumerated for each high-level effect event, a user interface part for providing a user with questions and responses regarding the s...

A method and apparatus for providing a fault-tolerant backup system such that if there is a failure of a primary processing system, a replicated system can take over without interruption. The invention provides a software solution for providing a backup system. Two servers are provided, a primary and secondary server. The two servers are connected via a communications channel. The servers have associated with them an operating system. The present invention divides this operating system into two ...

A detection circuit for remote release apparatus is disclosed which monitors a circuit carrying high-voltage between two connection points A and B and disconnects the circuit from the rest of a high-voltage network by automatically opening two power switches when a short circuit is detected. The ground fault protection system includes a pair of power switches for disconnecting points A and B from the remainder of a high-voltage network when a fault is detected in the high-voltage carrying circui...

An electric receptacle for trade size outlet boxes having a ground fault circuit interrupting mechanism incorporated therein. A receptacle housing includes contact jaws seated therein to receive the plug of a conductor leading to a load, electronic components to detect a ground fault and grounded neutral condition on the load side of the receptacle, plus a coil and trip mechanism to open the receptacle circuit on occurrence of a ground fault or grounded neutral condition. The complete receptacle...

An electric receptacle for trade size outlet boxes having a ground fault circuit interrupting machanism incorporated therein. A receptacle housing includes contact jaws seated therein to receive the plug of a conductor leading to a load, electronic components to detect a ground fault and grounded neutral condition on the load side of the receptacle, plus a coil and trip mechanism to open the receptacle circuit on occurrence of a ground fault or grounded neutral condition. The complete receptacle...

An improved control circuit which may be incorporated into a medical transcutaneous nerve or muscle stimulator for disabling the output from the stimulator to stimulation electrodes connected thereto upon the occurrence of an undesirable output event of the kind which may result in an electrical shock or burn to user of the stimulator. This disablement by the control circuit may be triggered when electrode impedance exceeds a threshold level, or when the current level of the output undergoes exc...