Abstract: An electromagnetic brake comprises an electromagnet arranged about a central axis SA; a slide movable with respect to the electromagnet in a slide actuation direction upon actuation of the electromagnet, and an air gap provided between the electromagnet and the slide through which a magnetic field passes when the electromagnet is actuated, wherein the slide is arranged radially inside or outside of the electromagnet with respect to the central axis SA. The electromagnetic brake is silent.

Abstract: A reed switch including a cylindrical enclosure with two ends, a first blade and a second blade is disclosed. The first blade has a first lead, a first web, and a first contact, and the first web is bent at a first angle as compared to the first lead. The second blade has a second lead, a second web, and a second contact, and the second web is bent at a second angle as compared to the second lead. The first contact is disposed adjacent to the second contact with a gap between them.

Abstract: A latching relay includes first and second coils and a common plunger operatively connected therebetween such that activation of the first coil moves the plunger in a first direction and activation of the second coil moves the plunger in a second direction, opposite the first direction, the first and second directions lying in a first plane. A limit switch includes a common contact and first and second coil contacts, where a position of the common contact is alternately switched between electrical connection to either the first or second coil contact based on a position of the plunger. A slide toggle accessible by a user is operatively connected to the plunger and slideable together with the plunger such that actuation of the slide toggle by the user causes manual actuation of the plunger. The slide toggle is slideable in a second plane parallel to the first plane.

Abstract: An electromagnetic device includes a spool having a cylindrical body with a through hole, a secondary coil formed in a spiral shape along an outer peripheral surface of the cylindrical body and formed with a closed circuit by metal plating, and a primary coil formed of a conductive wire wound around the secondary coil via an insulating material covering the secondary coil. An induced current, generated by applying a voltage to any one of the primary coil and the secondary coil, is allowed to flow to the other coil different from the one coil.

Abstract: A magnetic transfer module adapted to transfer a plurality of electronic elements. The magnetic transfer module includes an electromagnet and a plurality of transfer unit. The transfer units are connected to the electromagnet, each of the transfer units includes a ferromagnetic material element, and at least one of the transfer units includes a heating element. The electromagnet magnetizes the ferromagnetic material element, such that the ferromagnetic material element magnetically attracts one of the electronic elements. The heating element is disposed between the electromagnet and the ferromagnetic material element, and heats the ferromagnetic material element to demagnetize the ferromagnetic material element while being actuated.

Abstract: The invention relates to a rapid tri-state bidirectional switching device with three switching states of forward, backward and idle connection positions, comprising a shell and a movable electrode arranged within the shell for switching among the three states, wherein the movable electrode is provided with a movable contact point at either end thereof, the shell is provided with a fixed contact point at the front and rear sides thereof respectively corresponding to the movable contact points, a driving solenoid shaft is arranged above and connected to the movable electrode housing, and provided with a front locking notch and a rear locking notch, the device further comprises a release lock cooperating with a front locking notch and a rear locking notch to lock the movable electrode housing. The rapid bidirectional tri-state switching device is advantageous for its short switching time, small size and contact reliability.

Abstract: The present invention is provided with a fixed contact, a movable contact which selectively contacts with or separates from the fixed contact and a drive means which has at least an electromagnetic coil and drives the movable contact so that the movable contact comes into contact with the fixed contact. The drive means generates a first driving force for bringing the movable contact into contact with the fixed contact, and a second driving force larger than the first driving force for maintaining the contact state between the movable contact and the fixed contact.

Abstract: A method for controlling a normally closed relay includes: providing power to at least one of a first electromagnet and a second electromagnet via a power input port, then cause a first actuation member and a second actuation member to separate from each other, and the relay is then in an open state; and stopping providing power to the at lease one first electromagnet and the second electromagnet which being powered by the power input port such that the first actuation member and the second actuation member makes contact with each other, and the relay is then in a closed state.

Abstract: A method for controlling a normally closed relay includes: providing power to at least one of a first electromagnet and a second electromagnet via a power input port, then cause a first actuation member and a second actuation member to separate from each other, and the relay is then in an open state; and stopping providing power to the at lease one first electromagnet and the second electromagnet which being powered by the power input port such that the first actuation member and the second actuation member makes contact with each other, and the relay is then in a closed state.

Abstract: An electric supply circuit is provided for a switch actuating device containing an actuator, an electromagnetic drive for displacing the actuator from a first switching position to a second switching position, and a mechanical return device for returning the actuator from the second switching position to the first switching position. A magnetic fixing unit is provided for fixing the actuator in the second switching position and an electromagnetic releasing device is provided for releasing the fixation. The electric supply device contains a first capacitor electrically connectable to the electromagnetic drive and used for supplying electric power thereto and a second capacitor that is electrically connectable to the releasing device and supplies electric power thereto for releasing the fixation. An electric switchable connection is provided between the first and second capacitors.

Abstract: For controlling a magnetic flux of an electromagnet with a relay pulling characteristic and at least two stabile levels of values of a magnetic flux in a magnetic guide, controlling pulses of electric current are supplied into a winding of a magnetizing coil with obtaining a pulling force of a moving part of a magnetic guide of the electromagnet at least with one air gap, wherein the magnetic guide is formed at least partially of a magnetically hard material, two short-term pulses having an opposite polarity are supplied into the magnetizing coil on the magnetic guides of the electromagnet, for closing a magnetic circuit and minimization of magnetic resistance of the magnetic guide due, and holding or attracting force is provided until a supply of a second controlling pulse of electric current of the opposite polarity transferring the magnetic guide into a second stabile condition. Also, an electromagnet is proposed for an electromagnetic drive of an executing device.

Abstract: Disclosed is a solenoid type electromagnetic operating device which needs a relatively large current only for a limited short period at an excitation start initial stage and is adapted to achieve the speeding up at an excitation start stage and an improvement in responsiveness as well as power saving without increasing a power load on each of a drive circuit and power supply.

Abstract: Method for control of a proportional magnet comprising a magnet core, a magnet armature, a magnet coil for operating a control element in a shift valve or a proportional pressure-control valve, particularly a pressure-control valve for clutch operation in an automatic motor vehicle transmission, and comprising an electronic control device, whereby the magnet core may be moved back and forth between a control region and a hold region with a magnetic hold position of the magnet armature and a defined transition from the control region to the hold position may be executed and whereby mechanisms are provided for recognition of the movements of the magnet armature.

Abstract: An electromagnetically operated valve assembly (28) has a first solenoid (58) and a second solenoid (60). An armature (56) having a valve stem (54) coupled thereto is positioned between the first solenoid (58) and second solenoid (60). A controller (12) is coupled to the first solenoid (58), the second solenoid (60). A current sensor (49) is coupled to the first solenoid and generated a signal corresponding to the induced current in the first solenoid. The controller (12) changes a voltage applied to the first solenoid from a first polarity to a second polarity. The controller (12) is further configured to hold the voltage at the second polarity for a predetermined time period and a predetermined amplitude to decrease the induced current. The predetermined time period or the predetermined amplitude is determined based on the first signal.

Abstract: An electrical circuit arrangement for controlling a unit, such as an adjustment system for windows or a sliding sunroof, that is driven by a motor and is situated in a motor vehicle. The arrangement guarantees that, in the case of a short-circuit of circuit components, especially a control device operation of a motor is still possible, especially in a preferred direction of motor rotation, whereby the direction of rotation results in an opening of the unit and the short-circuit is caused by salt water for instance. Two circuit-breaker elements that operate the motor in either direction can be directly activated by an allocated circuit device which bypasses a failed control device. The remaining circuit-breaker element is blocked at least when the first circuit-breaker element is activated.

Abstract: The apparatus and method of regulating a control valve for a Diesel injection system comprises a fuel injector having a pressure amplifier preceded by the control valve (10), the slide (20) of the control valve (10) being moved by two spatially separated magnet coils (30, 32). During an electrical triggering of one of the two magnet coils (30, 32) with a control current, the respective other magnet coil (32, 30) is switched as a sensor, detecting the current induced in the sensor by a motion of the valve slide (20).

Abstract: An electromagnetic operator includes first and second coils wound coaxially. An armature partially surrounds the coils for channeling flux during energization of the coils. The armature may be formed of a bent plate and secured to a ferromagnetic support. A control circuit applies energizing signals to the coils during operation. Both coils are energized during an initial phase of operation. One of the coils is subsequently released or de-energized automatically. A timing circuit removes current from the second coil after a variable time period. The time period may be a function of the configuration of the timing circuit, such as an RC time constant, and of the energizing signal.

Abstract: An electrical control module and circuit for controlling a solenoid. The control circuit provides a constant voltage to a solenoid for a predetermined time period after which a pulse width modulated voltage is supplied. The circuit further includes components for reverse polarity protection, transient voltage protection, low gate drive voltage protection, reduced heat dissipation and improved magnetic drive under low input voltage conditions during application of the pulse width modulated voltage. The module may be used in conjunction with a single coil or a dual coil solenoid. The circuit may be utilized on a 12 volt or a 24 volt electrical system without adjustment.

Abstract: An actuating device for a motor used in a power window of an automobile which can drive the motor reliably to open the window even when the automobile is submerged in water. This device has a simple configuration is relatively small and inexpensive. This activating device comprises a drive circuit for a motor which has first and second relays to allow electric current to flow so as to drive the motor in either the forward or reverse direction. The contact of the second relay, which drives the motor in one direction, is used in such a way that the contact forms a part of an electronic circuit for the magnetic coil of the first relay. When the second relay operates, the electric circuit for the magnetic coil of the first relay is closed off. This activating device can ensure that a power window will be opened even if the automobile is submerged, and the first and second relay are switched ON at the same time.

Abstract: A permanent magnet device includes a permanent magnet having north and south pole faces with a first pole piece positioned adjacent one pole face thereof and a second pole piece positioned adjacent the other pole face thereof so as to create at least two potential magnetic flux paths. A first control coil is positioned along one flux path and a second control coil is positioned along the other flux path, each coil being connected to a control circuit for controlling the energization thereof. The control coils may be energized in a variety of ways to achieved desirable motive and static devices, including linear reciprocating devices, linear motion devices, rotary motion devices and power conversion.

Abstract: The invention relates to an electromagnetic actuator for a rapid linear motion with a limited length of stroke. The electromagnetic actuator includes a stationary arranged first coil (1, 6) and a second movable coil (2), with the winding of the stationary coil connected to controllable power source (7) and the winding of the movable coil is short-circuited without any galvanic connection to an external power source The ends of the winding of the movable coil of the electromagnetic actuator is short-circuited via a rectifier element (9), preferably a diode. The diode allows a current to be developed in one direction only in the winding of the second coil, said current being induced from an electromagnetic field generated by a current through the first coil. In this manner is a double-acting electromagnetic actuator with very low weight obtained, resulting in very rapid response and high reliability, due to the lack of any external electrical connections to the movable coil.

Abstract: An electromagnetic actuator has a large driving force and a good response speed and an image pickup apparatus obtains an image of a high resolution even by using a solid state image pickup device with a small number of pixels. The actuator comprises permanent magnetic field generating units for generating permanent magnetic fields and a current path forming unit which is relatively movable for the permanent magnetic field generating units and forms a current path which crosses the permanent magnetic fields by a current according to an input control signal. The permanent magnetic field generating units of the actuator generate two permanent magnetic fields in the directions which cross each other by, for example, two pairs of magnets. The current path forming unit has two coils each crossing the permanent magnetic field and winding shafts of those coils exist almost on the same line.

Abstract: Control circuit for electromagnet with two coils used to determine a call phase and a hold phase, and powered from a DC power source. The energy source comprises a current generator and a capacitor powered by this current generator. A control device controls two switches, in which the first switch controls discharge of the capacitor in the first coil during the call phase, and the second switch sets up current passing through a second coil during the call phase and the hold phase. The required current output from the current generator is thus reduced.

Abstract: A method for controlling armature movement in an electromagnetic circuit includes the steps of providing two spaced, facing electromagnets and an armature movable between the two electromagnets along a motion path; alternatingly energizing the two electromagnets for causing a reciprocating motion of the armature; detecting the actual moments of passage of the armature during each motion from one electromagnet to the other at least at two consecutive locations along the motion path; comparing signals representing the actual moments of passage with signals representing desired moments of passage of the armature at the two locations; and dependent upon deviations determined in the signal-comparing step, controlling the moment of de-energizing the momentarily releasing electromagnet and controlling the moment of energizing the momentarily catching electromagnet.

Abstract: An electromagnetic actuator includes an electromagnet having a yoke and an operating coil supported by the yoke and connectable to a controllable current supply for effecting a current flow through said operating coil. An armature is movable from a first position remote from the pole face of the electromagnet to a second, pole face-engaging position in response to a first electromagnetic force generated by a current flow through the operating coil. A resetting spring is coupled to the armature and opposes the first electromagnetic force. Further, a circuit is provided which is formed of a braking coil supported by the yoke and a switching element having open and closed states. The circuit is closed in the closed state of the switching element and is in the open state of the switching element.

Abstract: A driver circuit having logic circuitry which controls the coil and assoced contacts of a four pole double throw relay. The four pole double throw relay is toggled such that a large latching current flows through a first of a pair of solenoid coils of the magnetic-latching solenoid, while a relatively small current flows in the second solenoid coil of the magnetic latching solenoid in an opposite direction. Toggling the relay's coil causes the latching current to now flow through the second solenoid coil of the valve, while the relatively small current flows in the first solenoid coil of the magnetic latching solenoid again in the opposite direction.

Abstract: A solenoid driver circuit adapted for use with a digital magnetic latching olenoid which has first and second solenoid coils. The solenoid driver circuit includes a bridge circuit which receives a logic signal and first and second pulse signals. The solenoid driver circuit also includes a voltage source which provides a direct current and first and second resistors respectively connected to the first and second solenoid coils. The bridge circuit, responsive to the logic signal and the first pulse signal, provides a first current path from the voltage source through the first solenoid coil and the first resistor to ground and a second current path from the direct current voltage source through the second solenoid coil to ground.

Abstract: A switching circuit for use in a subterranean probe for switching between to two modes of operation used to perform a survey of a well borehole. The switching circuit comprises a first voltage bias network which is biased to a predetermined overvoltage criterion; a second voltage bias network which is biased to a predetermined negative voltage criterion; a switch; and a negative voltage blocking diode for blocking the predetermined negative voltage criterion for allowing the first voltage bias network to fully realize the negative voltage criterion.

Abstract: A method of adjusting the position of rest of an armature of an electromagnetic actuator, reciprocated against the force of resetting springs by an alternating energization of two spaced electromagnets; the position of rest being assumed by the armature in the de-energized state of the two electromagnets. The method includes the steps of detecting and determining actual values of an impact indicator representing an impact behavior of the armature as the armature impacts on the pole face of the capturing electromagnet; comparing the actual values derived from both electromagnets with predetermined desired values to form deviation values between the actual and the desired values; and, if deviation values are present, shifting the position of rest of the armature by an adjusting device until the actual values derived from both electromagnets correspond to a predetermined desired value.

Abstract: An electromagnetic circuit for controlling armature movement includes a holding magnet having a magnet yoke provided with a pole face; a solenoid connected to the magnet yoke; a movably supported armature arranged for reciprocating motion toward and away from the pole face along a motion path; an energizing arrangement for passing a current through the solenoid; a measuring pole leg attached to the magnet yoke; and a measuring pole carried by the measuring pole leg. The measuring pole is situated along the motion path of the armature and generates a signal upon passage of the armature by the measuring pole.

Abstract: When a trouble occurs in a cable, a feeding pass for another cable is ensured. In a feeding pass switching circuit, optical fibers are respectively connected to the terminals A, B and C. When a negative current is applied to the system in a state where a BRANCH2 is put in an open circuit and a TRUNK is grounded, a relay K1 is activated, and then a relay K2 is activated. Successively, when a positive current is supplied from the TRUNK, a cable connected to the TRUNK and a BRANCH1 is fed from both terminals. When the positive current is supplied from the BRANCH1 in a state where the TRUNK is put in a open circuit and the BRANCH2 is grounded, a relay K3 is activated. Successively, when the negative current is supplied to the BRANCH2, a relay K5 is activated. In such a manner, the power is fed to each feeding pass from one terminal.

Abstract: The arrangement for the control of an electromagnet is intended for an electromagnet consisting of a Stationary core 7, a pickup coil 1 through which current flows temporarily after the switch is closed, a holding coil 2 through which current flows during the operating state, as well as a moveable armature 8 moving in relation to the core 7. Within a magnetically responsive switching circuit 5, which is connected in series with the pickup coil 1, a coupling sensor 22 is included, consisting of at least one winding which is linked to at least a part of the magnetic field of the electromagnet at least then when the air gap is open. At the instant when the air gap is closed, the voltage spike induced in the sensor coil 22 switches a controllable semiconductor 11, connected in series with the pickup coil 1 into a state of high resistivity via an electronic switching circuit arrangement.

Abstract: A method of controlling a motion of an armature away from an electromagnet of an electromagnetic actuator includes the following steps: passing an electric current through a solenoid of the electromagnet for holding the armature at the electromagnet against a resetting force; interrupting the current flow through the solenoid at a desired moment for releasing the armature from the electromagnet; and impressing a current pulse of reverse polarity on the solenoid after interrupting the current flow for launching the armature from the electromagnet.

Abstract: Overcurrent protection arrangements including a relay comprising two coils wound on a common magnetic core and a PTC device coupled in parallel with the relay contacts. The arrangement comprises a circuit interruption element which has a normal state which permits the flow of a normal circuit current, I.sub.NORMAL, to pass through the system, and a fault state which permits the flow of at most a reduced current, I.sub.REDUCED, substantially less than I.sub.NORMAL. A first control element is coupled in series between the power supply and the load, and is functionally linked to the circuit interruption element so that when the current through the first control element increases from I.sub.NORMAL to a relatively high current, I.sub.FAULT, the first control element can convert the circuit interruption element into the fault state.

Abstract: An electromagnetic lock employs a pre-wound bobbin which is forced onto the E-shaped lamination stack of a magnetic core. The housing is configured in two longitudinal sections which are relatively pivotal to provide access for circuitry within the housing for both an outswinging and an inswinging door lock installation. The electromagnet also employs a circuit to sense the power supply to the electromagnet and to automatically select the operating voltage of the electrical coil.

Abstract: A solenoid actuator for controlling the flow of fuel used by an engine is provided. The solenoid actuator includes a solenoid housing, timing circuit housing and a solenoid connector. The solenoid housing contains a pull coil and a hold coil. First side and second side pull coil conductors are electrically connected to a first side and a second side of the pull coil, respectively. Similarly, first side and second side hold coil conductors are electrically connected to a first side and second side of the hold coil. The first and second side, pull and hold coil conductors all exit from the solenoid housing. A timing circuit housing containing a timing circuit receives the first and second side, pull and hold coil conductors. The second side pull coil conductor is connected to the timing circuit. A ground conductor extends from the timing circuit housing and is electrically connected to the timing circuit and the second side hold coil conductor.

Abstract: In one aspect of the present invention, an electromagnetic actuator is disclosed. The electromagnetic actuator includes a plunger adapted to move between first and second positions, a pull coil adapted to receive electrical energy and responsively produce a high electromagnetic force causing the plunger to move from the first position to the second position, and a hold coil adapted to receive electrical energy and responsively produce a low electromagnetic force for maintaining the plunger at the second position. A sensing device is included to detect the magnetic flux density produced by the coils and responsively produce a position signal having a magnitude responsive to the position of the plunger. Advantageously, signal conditioning circuitry receives the position signal, and de-energizes the pull coil in response to the position signal indicating that the plunger is at the second position.

Abstract: A contactor has an armature, a pull-in coil and a holding coil. When the system is energized through a first switch such as a thermostat, the low current holding coil is energized in preparation for holding the armature pulled in after the pull-in coil is energized and the armature has finished its power stroke. A solid-state switching device and the pull-in coil are connected in series between both terminals of a power source. A control circuit causes the solid-state switching device to be conductive the instant power is supplied to the circuit through the first switch. One embodiment of the control circuit is based on logic gates. RC circuits associated with the gates keep the solid-state switching device and pull-in coil conducting long enough for the armature to pull-in. After the solid-state switching device turns on, the transistor is controlled to turn off, deenergizing the pull-in coil while the holding coil holds the armature in until the first switch opens and power input is discontinued.

Abstract: A control system for an electromagnetic device prevents overheating of the coils to permit optimizing design parameters without the need for excessive safety factors. A pull coil circuit feeds a high current to pull windings for a preset time interval after receipt of an initiating voltage. A hold coil circuit feeds a holding current to holding windings with a reduced flux after receipt of an initiating voltage only if it exceeds a preset voltage threshold. The hold current is cut off when the initiating voltage falls below a preset threshold. The pull coil circuit is rendered inoperative for a preset time interval after current is discontinued to ensure adequate cooling between operations.

Abstract: An electromagnetic actuator having an integral capacitor and secondary coil for reducing opening and closing response times without the need for switching circuits. The secondary coil produces a magnetic field during energization which aids the primary coil in opening the actuator. A capacitor progressively reduces the current flow through the secondary coil as it charges up. During deenergization, the capacitor discharges through the secondary coil, producing a magnetic field which opposes the primary coil's residual magnetic field and aids the closing of the actuator.

Abstract: The invention relates to an electronic circuit arrangement for triggering excitation windings of electromagnetic components, provided with supplementary circuit elements, in particular free-running circuit elements, preferably solenoid valves (MV.sub.1 to MV.sub.n), whereby in order to provide a flexible open-loop control, the components are each connected in series to a controllable contact element (3). To reduce the degree of complexity of the circuit, the manufacturing price and the space requirement, it is proposed that the connecting terminals (1, 4) of this series connection lead directly, and the connections (2) between the components (MV.sub.1 to MV.sub.n) and the contact elements (3) lead via diodes (D.sub.1 to D.sub.n), respectively, to a collecting point (A, B, C), to which collecting points (A, B, C) is linked one and the same supplementary circuit-element configuration (T.sub.F,C.sub.L,10,11) shared by all components.

Abstract: Control circuitry is disclosed for electrical starters, contactors and the like having a starting winding and a serially coupled holding winding wherein the holding winding is shorted until the separable main contacts have closed which includes circuitry which obviates the need for relatively precise sensing of the position of the separable main contacts to control the holding winding. In one embodiment of the invention, the unshorting of the holding winding is delayed a predetermined number of cycles after the separable main contacts have closed to avoid the necessity of relatively accurate mechanical sensing of the position of the separable main contacts. In this embodiment a relatively less expensive field effect transistor or the like is used to short out the holding winding until the separable main contacts have closed. This allows the use of a relatively less expensive limit switch with a substantially smaller DC capability.

Abstract: An electric clutch actuator includes a coil having first and second windings, a first end of the first winding being connected to a source of electrical power and a second end of the second winding being connected through a switch such as an FET (field effect transistor) to ground potential. The opposite ends of the windings are connected together through another FET switch to the ground potential. An actuation circuit is responsive to a control signal to turn on the FET switches and cause electrical current to flow primarily through the first winding. The actuation circuit includes a timing circuit which turns off the FET connected to the opposite ends of the windings after a predetermined period of time to cause electrical current from the power source to pass through both of the windings.

Abstract: In a d.c. solenoid in which a thermistor having a positive temperature coefficient is connected in series with a main coil, a subcoil is connected in parallel with the series connection of the main coil and the thermistor, so that a large magnetic force can be produced at the solenoid energization starting time, and generation of heat from the thermistor can be suppressed to prevent burn-out of the main coil due to continuous current supply. Both the main coil and the subcoil, when energized alone, are capable of actuating the solenoid. The d.c. solenoid is applied to a valve in a vaporized fuel absorption system.

Abstract: A power control relay has a pair of solenoids one of which is briefly energized to open a pair of contacts and the other is opened briefly to close the contacts. A mechanical linkage maintains the contacts in their closed and open positions in the absence of solenoid energization. In a preferred embodiment of the invention, the solenoids drive a cam back and forth between two stable positions. The cam toggles an arm which opens and closes the power switch contacts.

Abstract: In a wire cut electric discharge machine, a plurality of magnetic field generating coils are arranged on the path along which a wire electrode is introduced into a workpiece, currents different in phase from one another are applied to the magnetic field generating coils thus arranged, so that the wire electrode is driven by the electromagnetic induction caused by the shifting magnetic fields which are produced by the magnetic field generating coils, whereby the wire electrode is smoothly fed without deformation. The leakage of magnetic flux is reduced by using a wire electrode made of magnetic material. The magnetic field generating coils are wound coaxial with the wire electrode, or they are provided so as to form magnetic fields perpendicular to the direction of insertion of the wire electrode, whereby the resultant wire electrode feeding device is simple in structure, but can produce a strong force of driving the wire electrode.

Abstract: An undervoltage tripping unit for a power line circuit breaker features a holding solenoid and a boostig solenoid having their associated plungers coupled to move together so as to be retracted against the force of plunger biasing springs when both solenoids are energized. Release of the plungers from the retracted position is used to trip the associated power line circuit breaker when the line voltage falls below a tripping voltage level. The holding solenoid is continuously coupled to the circuit breaker power input terminals. The booster solenoid is energized through a plunger-actuated switch so as to be de-energized when the plungers are fully retracted or in a position proximate thereto.

Abstract: The present invention pertains to a multi-stage solenoid in a housing having a first set of electrical contacts and at least a second set of electrical contacts. The solenoid also has at least two coil windings electrically distinct from each other and disposed sequentially in the housing. Additionally, the solenoid uses a timing circuit separately connected through a first set of contacts to each of the coil windings to control when they each receive electricity thereby activating the corresponding magnetically responsive element. The solenoid also uses a plunger having a flange of an electrically conducting material. The plunger is disposed in an original position in the housing in contact with one of the magnetically responsive elements.

Abstract: Techniques for controlling the operation of an electro-magnetic switch are provided. The current supplied to an exciting coil of the electro-magnetic switch is gradually increased until the contacts of the switch are closed. After the closure of the contacts, the exciting current is reduced to the minimum level needed to hold the contacts closed.

Abstract: A relay driver circuit, suitable for controlling a bistable relay, includes .[.a storage device which is charged to a first voltage level by a low current flow voltage source..]. .Iadd.a transformer which handles both an information signal and a control signal and a storage device. The control signal is provided by a low current low voltage source. .Iaddend.A first switching circuit couples the storage device to the bistable relay when the first voltage level exceeds a predetermined value. The charge on the storage device is dumped into the relay and forces it into a first state (set). A second switching circuit is coupled to sense the voltage on the storage device and the voltage on the low voltage source. When the voltage on the low voltage source falls below the voltage on the storage device, current flows from the storage device and forces the relay into a second state (reset). The reset time is within 100 .mu.s.