Electric Power Research Institute Incorporated

Francis A Holmes

Clive W Kimblin

Joachim V Heberlein

Paul G Slade

Joseph G Gorman

Roy E Voshall

John M Hicks

Joachim V Heberlei

The invention provides a technique for interrupting current employing a plurality of series connected vacuum arcs in parallel with a resonating circuit. At least one of the series vacuum arcs is subjected to an oscillating transverse magnetic field which produces modulations in the arc voltage. The arc voltage modulations initiate oscillations in the parallel resonating circuit, producing current modulations in the series connected vacuum arcs. The current modulations rapidly extinguish the arcs, interrupting the current. Use of a plurality of series connected vacuum arcs improves the recovery voltage hold-off potential of the circuit.

Series connected oscillating transverse field interrupter and method

An improved envelope for a vacuum-type current interrupter of the type having a pair of relatively movable electrodes. The envelope includes end portions which support the electrodes and an intermediate insulating portion which surrounds and is spaced from the electrodes. Baffles are provided along the interior surface of the insulating portion to break up continuous metallic vapor deposits on the interior of the envelope.

Current limiter vacuum envelope

An electrical circuit breaking device adapted for connection in circuit with an electrical conductor for interrupting the current passing through the latter is disclosed herein. This device includes an arrangement of larger and smaller electrode contacting surfaces which are separated from one another in a way which improves the continuous current carrying capability of the device while maintaining satisfactory interruption capability.

Electrical circuit breaking device and method

A vacuum arc current interruption device is installed in a current limiting circuit which includes a parallel resonant circuit. Means are provided for producing transverse lines of magnetic force in the arc gap between the electrodes in the vacuum enclosure. The energizing circuit for the magnetic field coils includes a capacitor bank employing unpolarized capacitors and a switch. After the capacitor bank is charged up, the switch is closed, discharging the capacitors through the field coils and producing lines of magnetic force in the arc gap. The field coils and capacitor bank together form a resonant field circuit having a characteristic resonant frequency which causes periodic reversals in the polarity of the lines of magnetic force. The oscillating magnetic field produces responsive oscillations in the arc voltage of an arc present in the arc gap of the vacuum device, which in turn causes oscillations of the arc current. When oscillations of sufficient magnitude are generated to produce a current zero, the arc is driven to extinction and the circuit current is commuted into a parallel current limiting impedance.

Vacuum arc current limiter with oscillating transverse magnetic field

A vacuum arc current switching device employs a shielding arrangement including a plurality of coaxially disposed cylindrical non-conducting members for minimizing exposure of the interior wall surfaces of the enclosure to vapor deposition of cathode material so as to prevent the formation of secondary arc terminals on the interior surfaces of the enclosure. The shielding being non-conducting prevents secondary arc formation which would otherwise permit arcing from the cathode to the shield and then back to the anode. The shielding further comprises annular transverse members disposed at the ends of the enclosure so as to protect the end wall surfaces as well.

Vacuum arc switching device with internal shielding

A vacuum type current interrupter is provided having a low mass movable electrode which can be moved into electrical contact with a stationary electrode for carrying large currents associated with power lines. A third electrode is positioned in the vacuum envelope in opposing relation to the stationary electrode and adjacent the movable electrode. When the stationary and movable electrodes are separated an arc will appear between their contact surfaces. The third electrode is conductively connected to the movable electrode so that the arc will spread from the latter to the relatively larger surface of the third electrode, to reduce local overheating of the electrodes during arcing.

Current interrupter electrode configuration

A pair of pancake-like coils have a coil axis substantially colinear with one coil mounted to a framework and the other coil mounted on a movable member. The coils are wound such that when electrically energized simultaneously the resulting magnetic fields are in opposition, thereby producing a repelling force therebetween. A spring is disposed between the framework and the movable member to urge the movable member in a sense opposite to the repelling force. A power supply is connected to the coil pair providing for a high initial energy transfer and a lower sustaining energy transfer. A shock absorber is mounted on the framework to arrest the moving member which is set in motion by the repelling force. An armature is attached to the moving member which enters the field of a holding coil as the moving member is displaced by the repelling force. When the holding coil is energized with the armature situated therein, the moving member is held against the spring force.

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Monroeville, PA, United States of America

Francis A Holmes