Abstract: In a circuit interrupter having a base with a stationary contact, a toggle link mechanism including an operating handle supported by the base for manually operating the circuit interrupter and a link rotatably connected at one end to the operating handle; a movable member pivotally supported on the base and having a movable contact on one pivoting end portion; a latch lever pivotally supported on the base for latching the link so that the movable member and the link are normally connected to hold the movable member against the force of a biasing spring so that the contacts are in engagement, and an overcurrent trip means including a plunger actuated responsive to a large overcurrent to strike and pivot the latch lever so as to release the link from the movable member to move and separate the contacts, the improvement comprising a pivotal support for the latch lever and the movable member on the base, allowing both bodily movement and pivotal movement only of the movable member; the pivotal support including a

Abstract: A circuit breaker structure having a faster trip unit characterized by a circuit breaker operator and a trip unit comprising a coil, a core, and an armature, and a hold-back bracket extending from and retaining the armature in a spaced position from the core so as to cause the magnetic field lines to flow through the bracket and the armature.

Abstract: The trip mechanism of a molded case type circuit breaker is actuated by a plunger that is integral with and axially extends from the end of a reciprocally-movable core member of a solenoid mounted within the breaker housing. The free end of the plunger strikes the trip bar of the breaker when the solenoid is energized in response to a current overload condition in the circuit being protected. The solenoid core member and plunger are mechanically locked in NO-TRIP position by spring-biased keeper means that is automatically released from its "lock" position by the magnetic field generated by the solenoid coil when it is energized. A spring automatically resets the trip-actuating assembly when the current-overload condition has been corrected and the solenoid coil is deenergized.

Abstract: A moulded case circuit breaker has a toggle-joint mechanism, articulated on a hook and on a moving contact support. The toggle joint includes a swivel pin movably engaged in an aperture of the hook. When tripping takes place, the released hook pushes the toggle-joint, via the swivel pin and aperture, into a broken position to accelerate opening of the contacts. In the closed position, the toggle-joint is practically perpendicular to the hook.

Abstract: An electricity power supply circuit including a trip switch having at least one fixed electrical contact (110, 111), a moving electrical contact (120, 121) facing the fixed electrical contact, a control member (130) movable between a working position in which the control member brings the moving electrical contact to bear against the fixed electrical contact and a rest position in which the moving contact is distant from the fixed contact, a holding spring (140) fixed to the control member, a cocking lever (150) movable between a locking position and an unlocking position, said lever including a notch (151) suitable for engaging said holding spring (140), a resilient member (160) suitable for urging the cocking lever towards the unlocking position, an electrical winding (170), and a magnetic body associated therewith.

Abstract: A circuit breaker having a trip delay mechanism characterized by a variable magnetic air gap that is adjustable to permit time delay at low level overcurrents to avoid nuisance tripping during motor starting.

Abstract: A circuit breaker with a magnetic circuit for delaying the trip function and characterized by a dual variable magnetic circuit air gap which allows a time delay at low level overcurrents, such that motor starting transient currents do not prematurely trip the circuit breaker.

Abstract: An electronically driven trip actuator for multipole industrial rated molded case circuit breakers is installed within a common housing with the circuit breaker operating mechanism. The trip actuator consists of a mechanical actuator cooperatively connected with a magnetic latch. The magentic latch arrangement holds the trip actuator against an actuating spring bias. Upon receiving an appropriate signal response, the magnetic latch releases, allowing the mechanical actuator to move into contact with the circuit breaker latch under the influence of the actuator spring. The arrangement of the mechanical actuator and actuator spring provides a low latching force to the magnetic latch, while providing a large trip force to the circuit breaker latch.

Abstract: A magnetic contact driver is arranged to drive a bridging contact out of electrical connection with a pair of fixed contacts to interrupt the current therethrough. The magnetic driver comprises a conductor winding embedded within notches in a plurality of metal laminations and an armature arranged transverse to the metal laminations. An auxiliary contact driver arrangement consisting of a pair of spaced electrical conductors arranged on the opposite side of the bridging contact is simultaneously energized for electrodynamic repulsion at the instant the magnetic driver winding becomes energized.

Abstract: A low voltage circuit breaker with remote switching function characterized by an insulating housing containing manually actuator for opening and closing separable contacts and a remotely controlled solenoid for opening the contacts, and the solenoid means being spring biased in the closed contact position only when the manually actuator is in the closed contact position.

Abstract: A variable composition switching device which comprises one basic modular component incorporating at least one controllable switching device, one direct switching control modular component and/or one indirect switching control modular component. This indirect switching control component acts on the basic modular component through a potential energy accumulation tripping device.

Abstract: A switch with a selective release having a stroke armature activated by an electromagnet in response to a release current to actuate a switch latch. A lever arrangement encloses a stroke armature in such a fashion that it can be swiveled by the stroke armature from a rest position into a position in which the stroke armature may be rapidly moved to impact on the latch.

Abstract: A circuit breaker capable of breaking an associated circuit when an overcurrent higher than a rated current keeps flowing through the breaker or upon a short-circuit current. Electric power path in the breaker is partly inserted through an arm of a magnetic material and holding a movable contactor plate of make-and-break contact means, an armature means is provided as pivoted at one end to the holding arm, and a tension spring means is provided between the other end of the armature means and the movable contactor plate to provide a contact pressure. The overcurrent flowing through the path causes a magnetic force to be induced in the holding arm, whereby the armature means is rotated to change the direction in which the force of the tension spring means acts on the movable contactor plate and the latter breaks the contact means.

Abstract: A circuit breaker having an automatically adjusting magnetic armature is provided. The magnetic armature includes a spring-biasing means to automatically maintain one end of the armature in the contact with the electromagnet and the other end away from an adjacent electromagnet. The magnetic armature includes a pair of slightly curved arms which are disposed about a pivot guide post. When current through the circuit breaker exceeds a predetermined amount, the end of the armature normally biased away from the adjacent electromagnet is suddenly attracted to the electromagnet. The force from the spring-biasing means is overcome, and the slightly curved arms of the armature pivot about the pivot guide post so that the armature contacts the adjacent electromagnet. A latch holder at the end of the armature becomes disengaged from a latch means to cause the circuit breaker to open.

Abstract: A tripping solenoid is used in connection with a lockout relay and has an adjusting means for positioning a plunger end with respect to a coil of the solenoid to predetermine threshold voltage, reluctance, and response time to activation of the plunger by a magnetic field of the coil. A spring opposes movement of the plunger in a first direction toward a push rod which is separated from the plunger and mounted coaxially therewith.

Abstract: In the cut-on position of the protective switch a movable contact element engages with a stationary contact element and at the same time is exposed to the action of a force displacing such movable contact element into a cut-off position. The movable contact element is arrestable in the cut-on position by means of a locking device which can be activated by an excess current. In order to reduce the number of movable parts to a minimum as well as to avoid parts which generate heat due to appreciable thermal losses, such locking device is provided with a substantially U-shaped locking element formed of a soft magnetic material. This locking element surrounds the movable contact element with play or clearance and is displaceably mounted transversely with respect to the flow of current in such movable contact element. At least one free leg end of the locking element is provided with a stop which in the cut-on position cooperates with a stop nose which is movable together with the movable contact element.

Abstract: An electromagnet has a movable core which is locked in rest position by magnetic effect. The movable core cooperates with portions of the magnetic field structure in such a manner as to form three sets of polar surfaces and gaps, of which one situated between the other two, can become saturated when the energizing flux of the winding achieves a certain threshold level. The device is particularly adapted to the actuation of circuit-breakers.

Abstract: A circuit breaker having a larger separation distance between a stationary contact 4 and a movable contact 6 in the automatic mode than in the manual mode. The pivot shaft 24 of a crank 13 is placed in a higher position than in a conventional circuit breaker, to thereby enable the arm 7 carrying the movable contact 6 to rotate through a greater angle. A stop plate 26 is provided to prevent the flex angle .theta. formed between a first link 11 and a second link 12 of a toggle mechanism 10 from becoming too small when the contacts are opened, which enables easy manual closure with the normal stroke of a switch handle 16 and avoids the need for a stronger spring 17.

Abstract: An automatic trip device for a circuit breaker includes a U-shaped stationary iron core disposed around a current-carrying conductor. The stationary core includes a semicircular recess on one leg thereof having V-shaped bearing surfaces formed at each end of the recess. A movable iron core is positioned across the legs of the stationary core and includes semicircular projection fitted into the recess of the stationary core. A shaft extends through the projection and pivots at each end in one of the V-shaped bearing surfaces. Tension springs connected between the stationary core and one end of the movable core produce opening rotational bias on the movable core. Electromagnetic force produced by an over-current flow through the conductor causes closing rotational movement of the movable core. The disclosed construction results in elimination of undesireable sound vibrations produced in prior art devices under conditions of current flow below overload level.

Abstract: A circuit breaker comprising an electrically insulating housing, an overcurrent sensor in the housing, a stationary and a movable contact in the housing, and a latch mechanism coupled to the movable contact. The latch mechanism is tripped in response to a sensed overcurrent; an overcenter spring is coupled to the movable contact for opening and closing the contacts with a snap action when the latch mechanism is tripped. An elongated handle member extends through a handle opening in the housing and is movable axially between a contacts open position and a contacts closed position. Handle link means couples the handle member to the latch mechanism and translates a longitudinal movement of the handle member into a rotational movement of the handle link to urge the latch mechanism into the contacts closed position.

Abstract: A fast opening contactor comprising an electrodynamic repulsion trip device associated to a standard contactor unit so as to operate the contacts towards the open position against the electromagnetic attraction force in response of a short-circuit current.

Abstract: The common trip mechanism of a multi-pole circuit breaker is supplemented by individual breaker pole trip mechanisms operating independently of each other in response to fault current flowing in its breaker pole to unlatch the movable contact arm operating therein for uninhibited, independent opening movement from its closed circuit position to a tripped open position motivated by the electrodynamic forces associated with its breaker pole fault current.

Abstract: A trip-free contact operating mechanism is provided with a latching system for maintaining a releasable cradle in its reset position. The latching system includes a lever mounted on a fixed pivot and having one end latchable by a cam member movable by a fault current responsive automatic trip means. A latch pin mounted in slots at the other end of the lever is engageable with the cradle for maintaining the latter in reset position. The latch pin is movable mounted on the lever in a manner such that the former may rotate about its axis, it may move lengthwise of the mounting slots, and the pin may pivot about an axis perpendicular to the pin axis and in the vicinity of one end of the pin.

Abstract: A plunger is normally held in a retracted, non-indicating position by a permanent magnet against the force of a spring biasing the plunger to an extended, indicating position protruding through an indicator cap. An electromagnet is selectively energized to develop flux in opposition to the magnet holding flux, whereupon the plunger pops to its indicating position. The cap internally mounts a pair of contacts which are bridged by a plunger mounted shorting ring incident with the plunger assuming its indicating position, thereby completing an external electrical indication circuit.

Abstract: A magnetic trip unit for a circuit breaker having an armature and a plunger; the armature completes a magnetic path through the poles of a permanent magnet; the armature and plunger are biased toward trip position but are held by the permanent magnet and may be restored to the position where the armature completes the path through the poles of the permanent magnet. A trip coil is provided surrounding the permanent magnet and armature. A casing of magnetic material surrounds the trip coil and extends below the armature; this casing also has top and bottom walls of magnetic material and an inner cup shaped sleeve bearing against the bottom wall and against one pole of the permanent magnet. Energization of the trip coil establishes an additional magnetic path through the armature and the one pole of the permanent magnet which opposes the magnetic force of the first mentioned magnetic path and permits the bias on the armature and plunger to move them to trip position.

Abstract: A tripping device for a circuit breaker combines the functions of a current transformer and trip actuator. The device comprises a core member, and an armature disposed in relationship to the core member to establish first and second magnetic circuits. A primary winding carrying load current of an associated circuit interrupter is coupled to the first magnetic circuit and a secondary winding is coupled to the second magnetic circuit, the secondary winding having a temperature dependent switching resistor connected across its output. The armature is movable between normal and trip positions. Low to moderate overloads cause the resistor to heat and switch to a lower resistance, thereby permitting increased current to flow in the secondary winding. This generates magnetic flux opposing the flux produced by the primary winding to lower the net flux in the second magnetic circuit. Magnetic forces on the armature thereby become unbalanced, allowing the armature to move to the trip position.

Abstract: A manually operable circuit breaker is provided with a spring powered trip-free contact operating mechanism. A fault current responsive thermal-magnetic automatic trip means is included as in an auxiliary means for operation of the circuit breaker from a remote location. Both the auxiliary means and the operating mechanism operate to open and close the same set of contacts.

Abstract: A molded case current limiting circuit breaker includes separable contacts, an operating mechanism releasable to effect automatic separation of the contacts, and a high speed electromagnetic trip device operable upon overcurrent conditions to release the operating mechanism and separate the contacts. The trip device includes a U-shaped pole piece disposed about a conducting path through the circuit breaker and a movable laminated armature mechanically coupled to the operating mechanism and magnetically coupled to the pole piece. The thickness of the armature is substantially greater than the thickness of the pole piece. During extreme overcurrent conditions electrodynamic force is produced upon the armature by magnetic flux in the pole piece. Upon saturation of the pole piece, force upon the armature continues to increase with increasing current due to electrodynamic force produced between the armature and the conducting path.

Abstract: A circuit breaker having an electronic fault sensing and trip initiating unit which provides increased versatility and ability to coordinate the circuit breaker with other interrupting and protective devices in a wide variety of electrical distribution systems. Electronic circuits and components are provided to vary the ampere rating of the breaker, to adjust current carrying capacity, to provide a long time delay trip, a short time delay trip and an instantaneous trip depending on the amplitude of high fault currents, to provide a ground fault trip, to shorten or lengthen the trip time for short time delay faults and for ground faults, and to provide shunt trip capability. The tripping mechanism is magnetic and mechanical, and includes a plunger movable between a trip and non-trip position controlled by an electronic switch in the electronic circuitry, and a toggle mechanism which is unlatched by the plunger when it moves to the trip position.

Abstract: An electromagnetic tripping device for protecting a printed circuit card by opening an electrical circuit of the card in response to an overcurrent of the circuit. The device includes contacts and an energizing coil which are connected in series with the circuit to be opened. When the contacts of the device are closed and the circuit current is normal, a magnetic holding flux provided by a bar magnet holds a plate in contact with two spaced and parallel side-walls between which is located the bar magnet. When an overcurrent occurs, the energizing coil produces a breaking flux which reduces the holding flux sufficiently so that the plate may be moved from the side-walls by a return spring, thereby opening the contacts and the circuit. When the plate is moved from the side-walls, an actuating rod which passes through an opening in the plate is projected out of the device housing to indicate the opening of the circuit.

Abstract: A bus-mountable, circuit-interrupting device, including an interrupting unit and a novel line-potential, manually-resettable operating mechanism for the unit, is usable in circuits in which faults may exceed the interrupting capability of the unit. A normally engaged pair of contacts in the unit is separable within an arc-extinguishing medium. The operating mechanism includes a robust, stored-energy operator, for separating the contacts, and a tripping mechanism, which selectively releases the stored operating energy. The tripping mechanism normally prevents release of the stored operating energy, and includes a high mechanical advantage lever-link system which permits a low latching force to counteract the stored operating energy. A ratchet-solenoid combination in the tripping mechanism selectively removes the low latching force.

Abstract: An actuation device which includes a holding magnet, an attracting magnet and an armature therebetween, both magnets being excitable by the same electromagnetic source. The armature comprises two half portions interconnected by a non-magnetic plate and operating such that upon saturation of the holding magnet with current, the armature will be disengaged by the holding magnet and drawn towards the attracting magnet.

Abstract: An electric wiring switch having an electromagnetic open-circuit shunt tripping device with a magnet armature that, when the tripping device is tripped, acts upon a latching shaft to release a latch upon the ocurrence of a fault current in an electrical circuit wherein the switch is connectible, and also having an indicating device lastingly indicating the tripping of the open circuit shunt tripping device, an operating button displaceable between a first position thereof wherein the switch is in an "on" condition and the operating button is spring loaded, and a second position thereof wherein the switch is in an "off" condition and the operating button is released from the spring loading, the operating button being formed with projection means extending therefrom which, in the "on" condition of the switch, are engaged behind corresponding extension means extending from the latching shaft for firmly retaining the operating button in the first position thereof, and which, in the "off" condition of the switch,

Abstract: A magnetic trip means for automatically opening a circuit breaker contact upon the occurrence of predetermined fault current conditions is constructed of a stationary yoke, an armature biased away from the yoke and movable toward the yoke for tripping of the switch, an actuating coil in series with the contacts, and a sealed capsule coaxial with the coil for obtaining selected tripping characteristics. Within the sealed capsule there is a movable magnetic core biased to a normal position extending substantially outside the coil. The core is movable inside of the coil toward the armature upon the occurrence of overload current conditions with movements of the core toward the armature being retarded in a controlled manner. Control is obtained by closely spacing the outer cylindrical wall of the core and the inner cylindrical wall of the capsule, and additionally by utilizing a viscous fluid within the capsule.

Abstract: Current-limiting device having a movable contact vigorously moved in the open circuit position by an electromagnetic repulsion device at the appearance of a short-circuit current. A retarding member is mechanically linked to the movable contact to delay the reclosing of the contact and to prevent a reclosing before tripping of the circuit breaker.

Abstract: A molded case multi-pole circuit breaker is provided with a solid state trip unit constructed to automatically open the breaker responsive to predetermined fault current conditions by actuating a permanent magnet latch. The latch and main conductors of the circuit breaker are constructed and arranged so that at very high short circuit currents, even if the solid state circuitry malfunctions, flux generated directly by current flow in the main conductors will buck the permanent magnet flux sufficiently to actuate the magnetic latch directly.

Abstract: An accessory apparatus package for electric circuit breakers includes a pivotal lever for latching a spring powered trip slide in a reset position. Either of two shunt trip solenoids acts on this lever to unlatch the slide, which springs to an actuated position, initiating tripping of the breaker. A UVR solenoid can also act on this lever to unlatch the slide. A powerful reset spring, controlled by the breaker operating mechanism, discharges as the breaker trips to return the slide to its reset position and, in the process, causes the lever and the solenoid plungers to be reset. All parts are operatively mounted by a common support affixed to the breaker.

Abstract: A motor controller having a single set of contacts and two contact operating systems is provided for operation and protection of a motor and the associated circuitry over a complete range of possible currents. For a normal motor starter operation and for fault current up to a predetermined value, an electromagnetic actuator is used to open the contacts a relatively small distance such as 1/4 inch. For higher fault currents a magnetic drive or linear slot motor opens the contacts to a greater spacing such as 1 inch. The slot motor opens the contacts very rapidly giving rise to good current limiting. The disclosed integral motor starter utilizes a bridging contact arm on which are mounted a pair of movable contacts which are aligned to engage a pair of stationary contacts when the disclosed motor starter is closed, completing an electric circuit to the controlled motor.

Abstract: An actuator having an armature plate urged to a stable position by a spring and which may be held in another stable position by a permanent magnet. Application of an appropriate current pulse to a coil within the actuator reduces the flux flow through and the magnetic force on the armature sufficiently to release the armature to the former stable position under the influence of the spring. Two magnetic circuits, one of which includes a non-working air gap, are employed, the non-working air gap serving to maintain a flux path, of a predetermined maximum reluctance, for the permanent magnet when the armature plate is in the former stable position.

Abstract: A manually operated snap acting switch having contacts in a circuit connecting an electric source to an electric load. The switch has contacts operated by a toggle mechanism and includes elements and mechanisms for causing the levers of the toggle mechanism to move to a tripped position and the contacts of the switch to open whenever the current in the circuit exceeds a predetermined value or in event of a power failure of the source. The elements and mechanism causing the movement of the levers to the tripped position and an opening of the circuit in event the source has a power failure include a spring-biased lever, a solenoid, which is continuously energized by the source, and a latch which is moved to released position by the solenoid plunger when the solenoid is de-energized. The lever which causes the toggle levers to move to the tripped position is held in an inactive position by the latch and moves to an active position when the solenoid is de-energized and the latch is moved to its released position.

Abstract: A circuit breaker which is characterized by its simplicity and the reduction of its parts. The direction of its manual operation and the direction of the movement of its contacts are at right angles. The contact operating mechanism and the latching mechanism interact by abutment of an overdrawn over-center toggle link with the latch lever of the device.

Abstract: Tripping devices, more particularly for circuit-breakers, in which a single model tripping device can be transformed by a simple operation, not requiring any dismantling, to obtain either a shunt or undervoltage type of operation. This result can be obtained by changing the relative position of a catch part of the striker, for example by rotation through 180 degrees in relation to a locking part.

Abstract: A magnetic trip assembly for use in a device such as an electric circuit breaker. The magnetic trip assembly includes a magnet and an armature arranged with respect to the magnet to coact with a pole face of the magnetic member which is in a plane normal to the magnetic plane of the magnetic member. An electrical load conductor is coupled to the magnetic member and establishes together with the magnetic member a magnetic field for closure of the armature in response to specified, excessive values (short circuit or overload values) of current passing through the load conductor. When the armature is operated to its closed position, a first portion of an actuating and latch member abutting against the armature is caused to move, in turn causing a captive, generally-cylindrical portion of the actuating and latch member to rotate.

Abstract: A combination motor-starter circuit breaker comprising a single set of separable contacts and providing the function of motor starting, circuit interruption, and current limiting. The combination employs three separate means for separating the contacts to provide these functions; a solenoid, an overcurrent trip mechanism, and a magnetic drive device for high overcurrent conditions. Arc rails and spaced conductive plates are provided to aid in extinguishing any arcs established. Movable contacts are mounted on a bridging contact arm which can be provided with two open positions, a first position for use during motor control wherein the contacts are separated by a relatively small distance and a second position for use during circuit interruption and current limiting.

Abstract: A circuit breaker with contacts which are not engageable when the electrical sensing unit thereof is energized above a predetermined level (at which the contacts would be tripped open if closed) even though the handle of the linkage mechanism of the circuit breaker is moved to the contacts closed (or contacts engaged) position.

Abstract: An electrically releasable permanent magnet latch includes a magnetic tube disposed within a U-shaped magnetic form. Disposed within the tube are a lightweight armature and a coil spring biasing the armature forward. An electromagnet coil is wound about the rear portion of the tube and a pair of permanent magnets are inside the frame along side the front portions of the tube. Energization of the coil creates a flux which bucks the permanent magnet flux to permit the spring to overcome the armature holding force whereby the spring operates the armature.

Abstract: An electrically releaseable permanent magnet latch includes a magnetic tube disposed within a U-shaped magnetic frame. Disposed within the tube are a lightweight armature and a coil spring biasing the armature forward. An electromagnet coil is wound about the tube and a pair of permanent magnets are inside the frame outboard of the tube. Magnetic diverter plates abut the magnets and are interposed between the magnets and coil. A collar on the tube provides a direct magnetic bridge to the diverters. Energization of the coil creates a flux which bucks the permanent magnet flux to permit the spring to overcome the armature holding force whereby the spring operates the armature.

Abstract: A plurality of single pole circuit breakers stacked side-by-side are interconnected by a tie rod connecting the magnetic armatures of their respective instantaneous trip means. When one pole is caused to trip because of a fault condition a driving cam formation on the releasable cradle of the faulted pole engages the armature moving it in the tripping direction substantially beyond the point required for releasing the cradle latch in the faulted phase. Substantial movement beyond cradle release is permitted even though the magnetic air gap at the armature is small in that after this gap is closed the magnet is moved bodily in the tripping direction. This added movement assures that the tie rod shall transmit sufficient motion to all non-faulted poles to cause tripping thereof.

Abstract: This trip device comprises a permanent magnet of cobalt-rare earth material and a plunger which is normally held in a withdrawn position by the permanent magnet. A tripping coil surrounds the plunger and, upon energization, develops tripping flux that opposes the holding flux from the permanent magnet, thereby to effect release of the plunger. In a position between the tripping coil and the permanent magnet, flux-diverting structure of highly permeable magnetic material is provided for shunting a portion of the tripping flux through a shunt path bypassing the permanent magnet. This shunt path contains a relatively large non-magnetic gap for limiting the tripping flux through the shunt path sufficiently to cause 30 percent or more of the tripping flux to pass through the permanent magnet in a direction opposite to the direction of the holding flux.

Abstract: A current limiting circuit breaker having for each pole, a pair of main contacts separable upon operation of a thermally and electromagnetically operable tripping device and a pair of auxiliary contacts for current limiting in series with the main contacts and in parallel with a transformable resistor having a positive temperature coefficient of resistance. The auxiliary contacts are separable when an electromagnet is energized by a fault current which simultaneously energizes a field magnet to produce a transverse magnetic field across the auxiliary contacts and the arc formed between them when separating. This simultaneous action of electromagnet and field magnet coacting for rapid contact separation and lengthening of the arc upon flow of a fault current serves to increase arc voltage almost instantaneously to that of the source, about which time the fault current is totally shunted into the resistor.