General Electric Company

Other

Edward K Howell

William James Premerlani

Kanakasabapathi Subramanian

John Norton Park

Joshua Isaac Wright

Thomas E Anderson

Bantval J Baliga

Bharat S Bagepalli

Christopher Fred Keimel

Joseph M Palmieri

Xuefeng Wang

Imdad Imam

Robert Joseph Caggiano

Kathleen Ann O'Brien

Fengfeng Tao

Donald L Watrous

Keith W Klein

Hsueh-Rong Chang

Brent Charles Kumfer

David J Lesslie

Kuna Venkat Satya Rama Kishore

Ira B Goldman

Long Que

Charles Stephan Pitzen

Robert G Hodgins

Henry G Willard

Earl W Roberts

Abhijeet Dinkar Sathe

A switching system is provided. The switching system includes electromechanical switching circuitry, such as a micro-electromechanical system switching circuitry. The system may further include solid state switching circuitry coupled in a parallel circuit with the electromechanical switching circuitry, and a controller coupled to the electromechanical switching circuitry and the solid state switching circuitry. The controller may be configured to perform selective switching of a load current between the electromechanical switching circuitry and the solid state switching circuitry in response to a load current condition appropriate to an operational capability of a respective one of the switching circuitries.

Electromechanical switching circuitry in parallel with solid state switching circuitry selectively switchable to carry a load appropriate to such circuitry

A motor starter is provided. The motor starter includes micro-electromechanical system switching circuitry. The system may further include solid state switching circuitry coupled in a parallel circuit with the electromechanical switching circuitry, and a controller coupled to the electromechanical switching circuitry and the solid state switching circuitry. The controller may be configured to perform selective switching of a load current from a motor connected to the motor starter. The switching may be performed between the electromechanical switching circuitry and the solid state switching circuitry in response to a load current condition appropriate to an operational capability of a respective one of the switching circuitries.

Micro-electromechanical system based electric motor starter

A gating voltage control system and method are provided for electrostatically actuating a micro-electromechanical systems (MEMS) device, e.g., a MEMS switch. The device may comprise an electrostatically responsive actuator movable through a gap for actuating the device to a respective actuating condition corresponding to one of a first actuating condition (e.g., a closed switching condition) and a second actuating condition (e.g., an open switching condition). The gating voltage control system may comprise a drive circuit electrically coupled to a gate terminal of the device to apply a gating voltage. The gating voltage control system may further comprise a controller electrically coupled to the drive circuit to control the gating voltage applied to the gating terminal in accordance with a gating voltage control sequence. The gating voltage control sequence may comprise a first interval for ramping up the gating voltage to a voltage level for producing an electrostatic force sufficient to accelerate the actuator through a portion of the gap to be traversed by the actuator to reach a respective actuating condition. The gating voltage control sequence may further comprise a second interval for ramping down the gating voltage to a level sufficient to reduce the electrostatic force acting on the movable actuator. This allows reducing the amount of force at which the actuator engages a contact for establishing the first actuating condition, or avoiding an overshoot position of the actuator while reaching the second actuating condition.

Gating voltage control system and method for electrostatically actuating a micro-electromechanical device

An electrical hazard detection system is used to detect energized ground terminals on electric receptacles. This condition may not be detectable by traditional circuit testers when hot and neutral wires have been switched and ground terminals have been electrically connected to the neutral wires. The user's body is used to provide a high-impedance path to true ground thereby creating an electric current from an energized ground terminal, activating a transistor, and illuminating an associated indicator.

Electrical hazard detection system

To avoid arcing when the breaker is opened, load current is diverted from a circuit breaker, before it opens, to a pulse forming circuit containing a precharged capacitor and a switch. Load current normally flows from a source of electric power to a load through a network comprising the breaker and a series connected controlled impedance. The pulse forming circuit is connected across the network. When load current is to be interrupted, the switch is closed to discharge a current pulse through the network, and the impedance of the controlled impedance is increased. These actions divert load current from the network to the pulse forming circuit. The breaker is then opened. The voltage across the capacitor first linearly increases from the precharge voltage to zero and then tends to increase in magnitude with an opposite polarity, i.e. that of the source of electric power. The voltage magnitude with opposite polarity then attainable across the capacitor is limited to a very low value, such as by a diode or SCR connected in parallel circuit with the capacitor. This limits the voltage across the opening breaker to avoid voltage breakdown across its contacts. It also permits use of a unipolar, e.g. electrolytic capacitor to increase the time during which the breaker can fully open. After the breaker is opened, the switch is opened, i.e. turned off, and remaining energy in the circuit is dissipated by a varistor. Various switching turn on and turn off circuits are disclosed.

DC circuit interrupter

Arrangement for arcless interruption of a-c load current in response to a current interruption command. Separable contact means serially connected with controlled impedance means, and parallel connected diversion means are intermediate the a-c source and the load. The controlled impedance comprises field effect transistors (FETs). Since FETs usually have only a single inherent junction, at least a pair of the FETs are oppositely poled so that load current can be cut off notwithstanding the direction of current flow when interruption is commanded. The pair of FETs may be connected back to back. An alternative embodiment has two branch circuits each comprising a FET and a separable contact means. Upon interruption load current is sequentially transferred from one to the other branch circuit and then to the diversion means.

Load circuit commutation circuit

An insulated field effect semiconductor device having source and drain regions extending to opposed surfaces of its semiconductor body is bidirectional and capable of blocking voltages in either of two opposing polarities and comprises a four terminal device having source and drain electrodes disposed on the opposed surfaces and a base electrode all ohmically connected to corresponding portions of the semiconductor body. An insulated gate is provided in a trench which extends into the semiconductor body for controlling the conductivity of a channel region extending within the base region between the source and drain regions. The device is free of source-to-base and drain-to-base short circuits. Control circuits enable this device to conduct or block both polarities of a high current AC voltage applied across its source and drain terminals while preventing undesired avalanche breakdown within the device.

Bidirectional field effect semiconductor device and circuit

A solid state switch connected across a pair of separable contacts for eliminating arcing across the contacts allows the contacts and the contact driver to be enclosed within an evacuated envelope. The vacuum environment allows the use of an inexpensive, highly conductive contact material, such as copper, without fear of chemical reaction.

Low voltage vacuum circuit interrupter

Load current is diverted from a circuit breaker, when it is opened, through a commutation circuit. The latter has a capacitor, inductance and solid state switch serially connected with the output of a bridge rectifier. The input of the bridge is connected across the breaker. The switch is turned on to discharge the precharged capacitor to form a current pulse, presenting an extremely low resistance across the bridge input and causing load current diversion.

Current commutation circuit

A solid state current limiting circuit interrupter for the arcless interruption of current through a protected circuit includes a pair of mechanically switched contacts electrically connected in series between the power source and the protected load. A solid state switch becomes electrically connected in parallel across the contacts when the contacts are opened to transfer the current to the solid state switch in a first state of voltage drop lower than arc voltage, and then in a second state of voltage drop higher than power source voltage in which stored energy is dissipated and current is forced to drop to zero to interrupt the circuit.

Solid state current limiting circuit interrupter

A bridging contact is arranged across two fixed contacts with a pair of parallel, closely spaced conductors serving as the bridging contact carrier. The conductors each form a pair of upper and lower links joined by means of a toggle pivot pin and are refrained from movement by means of a pair of tension springs. A high current pulse in opposite direction within the parallel conductors generates electromagnetic forces which propels the conductors apart. The bridging contact carried by the parallel conductors is thereby rapidly driven out of contact relation with the fixed contacts to interrupt the circuit.

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Simsbury, CT, United States of America

Edward K Howell