Westinghouse Electric Corporation

Eaton Corporation

The United States of America As Represented by the Secretary of

Alan B Shimp

Derek Albert Paice

Joseph C Engel

William E Beatty, Jr

Alfred E Maier

Joseph J Matsko

Gary F Saletta

Robert Tracy Elms

John A Wafer

Lance Gula

William John Murphy

Thomas N Meyer

Richard A Johnson

Walter W Lang

Paul Skalka

David J Uram

Gregg J Nissly

James I Wise

A circuit interrupter with a digital trip unit automatically sets the sampling interval appropriate for the 50 Hz or 60 Hz distribution system to which the interrupter is connected. In order to avoid falsely shifting the interval in response to distorted currents, the trip unit only changes the interval if the number of zero crossings of the current within a fixed number of samples is within two zero crossings of the number of zero crossings for an undistorted current of the other frequency for two consecutive time periods in which the fixed number of samples are taken. Furthermore, changes in the interval are only written into an EEPROM for use on power-up a fixed number of times to preclude disabling the EEPROM. In one embodiment, a 2 pole filter is utilized in the zero crossing counting circuit to eliminate false counts from noise originating in a chopper used in the trip unit power supply. In another embodiment, the zero crossing counting circuit is disabled unless external dc power is available for the trip unit which idles the chopper.

Digitally controlled circuit interrupter with improved automatic

A circuit interrupting device provides for operator selection of protection parameters for a neutral conductor separate from operator selected phase protection.

Overcurrent trip unit with separately adjustable neutral protection

A microprocessor based switch such as a circuit breaker generates digital rms representations of analog load currents from n samples of the analog currents per cycle synchronized to the line frequency, where n is an odd integer equal to a selected highest order harmonic to be detected plus 2. A routine determines whether the power system is 50 or 60 Hz, and automatically sets the sampling interval to provide exactly n samples per cycle for the connected source. Terminals for rapidly resetting an analog memory for calibration and field testing of a long delay trip are hidden behind a removable rating plug.

Electrical switching apparatus with digital trip unit and automatic

A microprocessor based switch such as a circuit breaker has a memory capacitor charged by the microprocessor to generate an analog equivalent of a digitally modelled heat state signal. A selected resistor discharges the capacitor at a rate which models a cooling rate of a load. Alternatively, the memory capacitor may be charged to a preset value and discharged at a rate representative of the time since a trip generates digital rms representations of analog load. Terminals for rapidly resetting the analog trip memory for calibration and field testing of a long delay trip are hidden behind a removable rating plug.

Electrical switching apparatus with digital trip unit and memory reset

A circuit for controlling the orientation of magnetic fields is provided. The circuit has particular application to a flux shunt trip device in a circuit breaker. The flux shunt trip device has a spring-loaded plunger which when released to its extended position causes the circuit breaker to trip. Under normal operating conditions, the plunger is maintained in a retracted position by the force of a permanent magnet. A trip coil is mounted adjacent to the plunger. When the trip coil is energized a magnetic flux is generated opposing the magnetic flux of the permanent magnet. When the opposing flux neutralizes the flux of the permanent magnet the spring-loaded plunger is released to its trip position. A control circuit is provided to aid in maintaining the plunger in its retracted position under high current conditions close to, but below, the trip value. This control circuit acts to reverse the direction of current through the trip coil under these conditions such that a magnetic flux aiding that of the permanent magnet is generated. If a trip current is detected, the control circuit allows the current to flow in the normal direction through the trip coil, thus generating a magnetic flux opposing the permanent magnet which causes the plunger to be released and the breaker to trip.

Circuit for controlling the orientation of a magnetic field

A multipurpose combination barrier and auxiliary current transformer board is provided for a circuit breaker. The board is located at the rear of the circuit breaker housing to close an open portion of the housing and act as a barrier to prevent contact with internal circuit breaker components. Vent holes, provided in the bottom portion of the board, allow heat generated within the circuit breaker to be exhausted to the atmosphere. The top portion of the board serves as a mounting plate for the auxiliary current transformers. The top portion of the board is formed from a printed circuit board having an electric circuit disposed thereon for the connections between the main current transformers, auxiliary transformers and the electronic trip unit. Connectors are provided on the printed circuit board adjacent each auxiliary current transformer to connect the main current transformers to the printed circuit. Another connector is provided on the board to connect the printed circuit board to the electronic trip unit. Thus, time consuming wiring connections are greatly reduced.

Combination barrier and auxiliary CT board

An organo-platinum complex of the formula ##STR1## wherein X and Y have the same meaning of a halogen, oxyanion or carboxylate, respectively or X is an oxyanion or dicarboxylate together with Y, and L.sub.1 and L.sub.2 are bonded together to form one of silicon containing diamine compounds selected from the group consisting of ##STR2## in which R.sub.1, R.sub.2 and R.sub.3 are a lower alkyl or phenyl, respectively, and n is an integer of 0 or 1, and use of the complex for an anti-tumor composition.

Electric circuit for operating trip circuit of a circuit breaker

A circuit breaker characterized by a circuit breaker structure having separable contacts and a releasable mechanism which mechanism is retained in untripped position by a latch including a rotatable trip bar. A solenoid, that is operable automatically in response to overload current conditions, is located adjacent to the trip bar and has a plunger movable parallel to the axis of the trip bar. A lever is disposed between the plunger and the trip bar to translate longitudinal motion into rotational trip bar motion.

Circuit breaker with interface flux shunt trip

A method for and an apparatus for use in testing a circuit breaker, the circuit breaker having at least one current sensing means, such as a current transformer, trip circuitry, and circuit interruption means. In the method, a low voltage A.C. source is provided; and means for generating an A.C. signal is also provided, the means for generating an A.C. signal having the capability to vary the magnitude of the voltage of the A.C. signal. The low voltage A.C. source is connected with the means for generating an A.C. signal; and the means for generating an A.C. signal is connected with a current sensing means of the circuit breaker. The current sensing means is energized with an A.C. signal; and the magnitude of the current in the A.C. signal is monitored. The magnitude of the current in the A.C. signal and the state of the circuit interruption means in the circuit breaker is compared with a predetermined magnitude of A.C. at which the circuit interruption means in the circuit breaker in proper working condition would be placed in an open state to provide an indication of the condition of the circuit breaker. An apparatus is provided for use in testing a circuit breaker adapted for connection with a low voltage A.C. source and with a current sensing means, such as a current transformer, included in the circuit breaker. The apparatus includes means for varying the magnitude of the voltage of the low voltage A.C. source, and means for varying the magnitude adapted for connection with the low voltage A.C. source.

Method for testing a circuit breaker using a three terminal current

A circuit breaker characterized by a pair of separable contacts, trip means operable automatically in response to overload current conditions to open the contacts which means include a rotatable trip bar biased in an untripped position, and interlock means including a manually operable button for rotating the trip bar to a tripped position when the button is pushed and for rotating a cam into tripped and untripped positions when the button is rotated.

Circuit breaker with replaceable rating plug interlock and push to trip

A circuit breaker and alarm device for a circuit having a series connected interruptible current device whereupon a circuit breaker tripping means, attached to said circuit breaker, is adapted to obtain an output voltage of one polarity upon the tripping of the circuit breaker. A circuit breaker resetting device, attached to said circuit breaker, is adapted to obtain an output voltage of reverse polarity upon the resetting of the circuit breaker. A voltage-detecting circuit for sensing the voltage produced by the tripping or resetting of the circuit breaker. A current detecting circuit which produces an output upon detecting an output produced by the voltage-detecting circuit. An alarm circuit which is connected to the current-detecting circuit is thereby caused to essentially instantaneously upon the tripping of the circuit breaker, to energize and remain energized until the resetting of the circuit breaker.

Circuit breaker with alarm

A circuit breaker comprises an adjustable trip unit having electronic circuitry for initiating a tripping command upon detection of overcurrent conditions. The trip unit includes an externally accessible interchangeable plug-in rating adjuster removably supported on the housing of the circuit breaker by a threaded rod and tube. An interlock mechanism cooperates with the trip bar of the circuit breaker and secured mechanism to insure that only when a compatible rating adjuster is properly seated in the housing and the threaded rod is completely engaged within the threaded tube will the circuit breaker mechanism be removed from the trip-free condition. Coordination of a proper rating adjuster with a corresponding trip unit and circuit breaker is achieved by coordinating the lengths of the rod and tube and the position of the threaded portions thereof such that only a rating adjuster which is electrically compatible with a particular circuit breaker and trip unit will properly engage the threads of the tube to remove the circuit breaker from the trip-free condition.

Circuit breaker with interchangeable rating adjuster and interlock means

An improved discriminating circuit breaker system for use with an electrically grounded direct current power distribution system. A three-tier safeguard system is provided to insure proper operation of the breaker should a fault occur. The basic components include the electrically operated circuit breaker and a control circuit therefor. The control circuit sends a control signal to the breaker to operate it depending on whether a illegitimate load is detected on the power distribution system. This detection process utilizes: a pilot wire through which any control signal flows; an alternating current (a.c) signal generator to superimpose such a signal on the transmission line; a current detector to sense the a.c. level and produce a control signal if its current value exceeds a maximum level; a voltage detector to sense the voltage level of the a.c. signal and to produce a control signal if the value falls below a minimum level; and a switch system responsive to the control signals and in series with the pilot wire to activate the opening of the circuit breaker when the wire is open or when a control signal is produced.

Discriminating circuit breaker protection system direct current power

An electronic control system and associated circuit breaker is taught in which the effect of in-rush current on mining equipment, for example, in regard to tripping is minimized even though a single phase fault of an equal magnitude is adequately provided for. This is done even though the same circuit breaker system and circuit breaker for both situations is utilized. A resistive capacitive series network is utilized to separate the ripple frequency from the DC value of the overload current being sensed. If the ripple component is relatively high for a given amount of overload current in the lines to be protected, then that is indicative of a single-phase fault for which circuit breaker tripping should be provided. If on the other hand the same amount of current causes a ripple component of a relatively low value, that is indicative of balanced three-phased overload which is usually indicative of in-rush or spurious transients. In any case, higher values of overload will cause other portions of the circuit to trip for safety. A time delay is provided at the output of an operational amplifier interconnected with the series resistive capacitive circuit. The time delay provides further protection against spurious tripping. Furthermore, tuned feedback is provided for the operational amplifier to distinguish between the ripple frequency of a single-phase fault and the ripple frequency of a three-phase fault.

Single-phase fault detecting circuit breaker

A ground fault detecting circuit interrupter is taught. A ground fault is sensed by utilizing a summing transformer interconnected with the three-phase current transformers for normal fault detection. The turns ratio between the primary winding and the secondary winding of the summing transformer is kept purposely high so that the excitation current for the current transformers is made relatively small when compared to the normal secondary current of the current transformers. This has the effect of improving the accuracy of the normal fault detecting portion of the circuit breaker. The relatively high turns ratio between the primary and second of the summing transformer usually supplies insufficient current to directly actuate the trip coil of the circuit interrupter on the occurrence of a ground fault. However, this latter current is utilized to charge a capacitive storage element after a ground fault has been sensed. When the capacitive storage element is fully charged, it is switched into a circuit disposition suitable for discharge through the trip coil of the circuit interrupter with sufficient current flow to open the separable main contacts of the circuit interrupter.

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Monroeville, PA, United States of America

Alan B Shimp