Abstract: A relay coil associated with a pair of contacts connects an electrical source to a load. Actuation of a coil sensing element by a trigger input signal supplies current to the coil. In response to the trigger input signal the load sensing element supplies a latch maintain signal to a switching element which becomes conductive to establish current flow to the load. As long as the load sensing element detects current to the load the switching element remains conductive for a "latched" state. Interruption of current to the load converts the elements to an "off" state until another trigger input signal is transmitted to the load sensing element.

Abstract: Solenoid activation circuitry utilizing a high voltage for energizing a low voltage solenoid from a low voltage source of power comprising a capacitor having first and second terminals with the second terminal being connected to ground. A converter is provided having an input and an output. The input of the converter is adapted to be connected to the low voltage source of power and the output of the converter is connected to the first terminal of the capacitor. A device is provided for sensing the voltage on the first terminal of the capacitor to ascertain when the voltage on the first terminal of the capacitor has reached a predetermined high voltage which is substantially above that of the low voltage of the power source. A switch is provided and is adapted to be connected to the solenoid for causing the capacitor to discharge into the solenoid when the predetermined high voltage has been reached on the capacitor to overcome the initial air gap in the solenoid to move the solenoid to an actuated position.

Abstract: A bistable relay circuit adapted to be operated from a two polarity supply of predetermined voltage, includes a control relay having a coil exhibiting hysterisis, and at least a first single pole, double throw switch, having one pole contact and two non-pole contacts. The control relay coil has a resistance value which is low compared to the resistance value of the first resistor, while a current operatively flowing therethrough is insufficient on its own to energize the control relay. A first resistor is in series with the coil of the control relay. The series combination of the control relay coil and of the first resistor are connected to the power supply. The circuit also includes a second single pole, double throw switch, having one pole contact and two non-pole contacts. A second resistor is connected to the pole contact of the first switch, and to one of the non-pole contacts of the second switch, and a capacitor is connected to the pole of the second switch and to one polarity of the power supply.

Abstract: An advanced latching circuit (14) is used for latching a compressor (16) to a power source (18). The circuit includes the solenoid (32) of a compressor relay. A first set of contacts (28) of the compressor relay, a capacitor (34) and a resistor (36) are connected in parallel with each other and in series with the solenoid (32). Power supplied to the latching circuit (14) with the capacitor discharged energizes the solenoid (32) and latches the circuit. The opening of the latching circuit (14) by a safety switch (38, 40) deenergizes the solenoid to disconnect the compressor from its power source and charges the capacitor (34). The solenoid cannot be reenergized to reactivate the compressor until service personnel remedy the heat pump malfunction and interrupt power to the latching circuit (14).

Abstract: A mobile storage system includes movable carriages that are stoppable by solenoid operated mechanical safety brakes. The solenoids are controlled by an electrical circuit that includes a safety floor and/or a safety sweep. Actuating the respective safety switches activates the circuit to energize the solenoids for operating the brakes. The safety floor portion of the circuit is designed to energize the brake as long as a safety floor switch is actuated. The safety floor circuit portion contains a timing device that holds the solenoid in the energized condition for at least 3 seconds after deactuation of the actuated safety switch, so that a person walking across the floor does not cause the solenoids to chatter. The safety sweep circuit contains first timing means for deenergizing the solenoid approximately 3 seconds after safety sweep switch actuation. If the actuated switch remains open after approximately 5 minutes, or if a safety sweep switch fails, an audio alarm sounds.

Abstract: An electronic postage meter which has a computer and apparatus for printing a postage value, wherein the computer includes instrumentalities for authorizing printing the postage value, and has shutter apparatus which is operable for alternately preventing and permitting operation of the postage printing apparatus, and has interposing apparatus which is operable for alternately preventing and permitting operation of the shutter apparatus, is provided with an improvement for controlling the operation of the interposing apparatus.

Abstract: An improved solenoid driver control circuit is disclosed in which solenoid current is sensed and provided as an input to a comparator means comprising two separate comparators (24, 25). The comparator means receives a solenoid current sense signal (45) and maximum and minimum reference threshold levels which determine maximum and minimum current limits (I.sub.max, I.sub.min ; H.sub.max, H.sub.min) for solenoid current during initial pull-in excitation and subsequent hold excitation. Pull-in time (T.sub.1) is defined by a monostable multivibrator (33) reacting to a control pulse (41) to produce a predetermined pull-in time pulse (43) such that the pull-in time is independent of sensed solenoid current. During pull-in time a boost driver switch (53) applies high boost voltage to a power source terminal (16) which supplies solenoid current, and in response to achieving the maximum pull-in current limit (I.sub.max) lower battery voltage is provided at the power source terminal.

Abstract: The system includes a battery state-of-charge monitoring circuit which is operable to produce a signal change when there is a change in the battery charge from an acceptable charge to a substantially reduced charge. The signal change from the monitor is connected to control a lock-out relay to disable a control circuit for a load controller for battery powered equipment which is to be locked out. A current detecting device is connected to detect the presence of current in the control circuit of the controller and is connected to hold off the lock-out operation of the lock-out relay while current is flowing in the control circuit to thereby assure that the lock-out of the load occurs after a normal interruption of the load control circuit.

Abstract: An electrical equipment controller is provided with a delayed turn-off capability. A thermostat is in series with a control relay. The thermostat is further in parallel with the series combination of a relay latch contact and a first positive temperature coefficient (PTC) device. A second PTC device is connected in parallel with the control relay. The arrangement of first and second PTC devices provides a predeterminable drop-out relay including compensation for ambient temperature changes.

Abstract: A new method of activating existing electric solenoids which reduces the power required up to 90%, reduces the size of wire required, extends solenoid life, and facilitates installation. This is accomplished by adding an encapsulated module at the end of the electrical line just ahead of the solenoid. The principles used are that a solenoid requires a much higher level of energy to actuate than to keep it actuated. Charging a capacitor slowly then allowing it to suddenly discharge into the coil eliminates the inrush load demanded on the source, while a series resistance then keeps the load at a low level by acting as a current limiter.

Abstract: A battery operated, portable actuator for an inductive load such as an electromagnetically actuatable photographic shutter includes an initiating capacitor for initiating acutation of the load, and a continuing holding circuit portion for continuing energizing the load after discharge of the initiating capacitor. The capacitor is connected to be charged by the output of a voltage multiplying rectifier which is alternately turned ON and OFF according to the instantaneous voltage across the capacitor, being turned ON when the voltage is low, and OFF when the voltage is high. The continuing circuit portion is arranged to feed time-spaced current pulses to the load, and a diode is connected across the load so that its own inductive nature holds it energized during the intervals between the pulses. The duration of the energizing current pulses is increased in response to fall-off of the battery output voltage.

Abstract: A method and apparatus for driving an electromagnetic device includes two coils which selectively attract and repel a moving body. In order to allow a quick switching of the moving body between being attracted by one coil and the other, the current through the coil which is not holding the moving body in its magnetic field can be made to be a level higher than the current to the coil which is holding the body in its magnetic field. By reducing the current to the coil that is holding the body, the body can be rapidly switched to be within the magnetic field of the other coil. In addition, the currents to the respective coils can be increased before this switching occurs. Structure can also be provided across the coils to quicken the time it takes for the magnetic field to dissipate.

Abstract: A bistable relay circuit adapted to be operated from a two polarity supply of a predetermined voltage, includes a control relay having a coil exhibiting hysterisis, and at least a first single pole, double throw switch, having one pole contact and two non-pole contacts. The control relay coil has a resistance value which is low compared to the resistance value of the first resistor, while a current operatively flowing therethrough is insufficient on its own to energize the control relay. A first resistor is in series with the coil of the control relay. The series combination of the control relay coil and of the first resistor are connected to the power supply. A steering relay has a coil and at least a second single pole, double throw switch, having one pole contact and two non-pole contacts. A single pole, single throw switch is in series with the coil of the steering relay. The series combination of the steering relay coil and the single pole, single throw switch is connected to the power supply.

Abstract: A current controlling device comprises an input circuit for receiving a driving signal, means for supplying a first reference voltage or a second reference voltage lower than the first reference voltage, a detecting resistor for detecting current flowing through an electromagnetic winding, and means for supplying the electromagnetic winding with a starting current and a holding current. The starting current initially rises then is maintained at a constant value based upon the detected voltage of the detecting resistor and the first reference voltage. The second reference voltage is supplied in place of the first reference voltage after a predetermined period of time and continues to be supplied until the driving signal ends. The holding current is maintained at a constant value lower than said constant value of the starting current based upon the detected voltage and the second reference voltage. Both the first and second reference voltages are controlled to be constant voltages.

Abstract: An electromagnetic contactor for controlling the opening and closing of an electric circuit for an electric motor or the like, including a mounting pedestal including a rectifier circuit therein, a stationary iron core disposed thereon and having an operating coil wound around the same, and a movable iron core disposed oppositely to this stationary iron core to be spaced therefrom by a predetermined spacing thereby to change an AC voltage applied to the operating coil to a direct current. The stationary iron core is composed of a bar-shaped magnetic member while the movable iron core is substantially U-shaped.

Abstract: In a circuit for driving a latching relay for use in a telephone set, a capacitor is charged from a battery, and when the capacitor is charged to a predetermined value, the capacitor is disconnected from the battery. Thereafter the latching relay is driven by the discharge current of the capacitor. With this circuit, it is possible to prevent unnecessary consumption of the battery.

Abstract: A D.C. power control for a D.C. solenoid actuator which may be used for a D.C. solenoid operated valve uses a timer circuit for switching from an initial high pull-in power after a predetermined delay to a low hold power for the valve solenoid utilizing a pulse control where the valve "on" time is held constant and the "off" time is varied. The pulses are high frequency to prevent the valve from switching with each of the pulses while enabling the average current in the valve solenoid coil to be controlled independently between the pull-in and hold current values.

Abstract: A circuit for driving a solenoid valve having a valve which is driven by an exciting current flowing through a solenoid coil to open/close the solenoid valve comprises at least one ON-OFF switch which operates in response to the movement of the valve, and a stand-by exciting current to intermittently energize the solenoid coil is supplied whereby the valve is oscillated at a position just before starting to open or close the solenoid valve. The oscillating state of the valve reduces the static frictional force that would otherwise act on the valve can be eliminated and the high speed operation of the solenoid valve can be realized.

Abstract: A solenoid power control circuit provides full power during lifting and reduced power during maintaining a lift condition in a lifting solenoid of an electric arc stud welding gun. During the stud lifting portion of a stud welding process, relatively high power is provided to the lifting solenoid to effect work necessary to accomplish the lift; but after a lifted condition has been achieved, the invention phases back power to reduce the energy dissipated while the stud and the lifting solenoid are maintained in lifted condition. A relaxation oscillator having two different charging time constants that can be selected to provide long or short phase delay is employed for the phase modulation control of lifting solenoid energization.

Abstract: A device is provided that begins an electrical starting mode in a parallel circuit configuration providing an improved speed of response and after an interval of time, current is switched to a series circuit configuration for operation during a run mode. The device is initially energized at several times the power normally required to activate a coil and switching means is thereafter utilized to reduce power to a normal requirement soon after the coil is energized.

Abstract: A power-saving relay circuit for reducing power consumption from a power supply comprises a relay including a selectively energizable relay coil, a plurality of movable contactors, and a plurality of fixed contacts including first and second fixed contacts associated with each of the movable contactors. Each of the movable contactors is normally in electrical contact with the first fixed contact and responsive to energization of the relay coil for breaking the electrical contact with the first fixed contact and for making electrical contact with the second fixed contact. A current limiting circuit is coupled in electrical series circuit intermediate a selected one of the second fixed contacts and the relay coil. The movable contactor associated with the selected one of the second fixed contacts is capable of being coupled in circuit with the power supply for completing an electrical circuit through the current limiting circuit for energizing the relay coil.

Abstract: An electric starting apparatus for cranking an internal combustion engine. The electric starter is of a type that has solenoid pull-in and hold-in coils that when energized cause a solenoid plunger to shift which in turn moves a pinion into mesh with the ring gear of the engine. The hole-in coil can be energized directly from a battery when a manually operable start switch is closed. The energization of the pull-in coil is controlled by a Darlington transistor located in the solenoid housing. The transistor is biased conductive when the start switch is closed and nonconductive when the start switch is opened.

Abstract: An irradiation device including a series arrangement of an ultraviolet radiation source (5), a first switch (3) and a second switch (4). Under normal conditions the radiation source (5) is switched on and off by the first switch (3). The second switch (4) is operative only if the first switch (3) fails. By means of a simple circuit (7, 20, 17, 6; R), the defective device cannot be switched on again.

Abstract: A magnetically operated AC switching device, such as an AC electrical contactor, is operable with a delay-on-dropout feature to permit safe shutdown of equipment energized therethrough in case of power failure. The device includes an AC pickup winding which is energizable from an AC power source and a DC holding winding which is electrically connected to a rectifier for energization of the holding winding with DC power from the AC source. A capacitor is also electrically connected to the rectifier in parallel with the holding winding for energization with DC power from the AC source. Upon energization of the device, the AC pickup winding moves fixed and movable contacts of the device into engagement, and the DC holding winding maintains them in engagement. The AC pickup winding can remain energized without burnout; and upon power dropout the capacitor supplies DC power to the holding winding for an instant to provide a slight delay in the separation of the contacts.

Abstract: An electrical circuit, controlled by an electromagnetic relay, comprising an electromagnetic relay having relay contacts for controlling current flow to a load in use, and a relay winding which, when energized, causes closure of said relay contacts. First manually operable switch means is provided for energizing said relay winding, and a feed connection is provided from said relay contacts to said relay winding whereby said winding is energized while said contacts are closed. A second manually operable switch means for short circuiting said relay winding is provided to permit said relay contacts to open. An overload protection winding is physically associated with the relay winding and connected in series with the contacts, said overload protection winding being such that when the current flowing therethrough exceeds a predetermined value the electromagnetic effect generated opposes the electromagnetic effect of the relay winding to a sufficient extent to permit said relay contacts to open.

Abstract: A circuit for automatically closing a backup remote feed loop upon interruption of the remote feed loop of a remote feed device for supplying electrical users by means of DC series feed has a holding winding and a response winding disposed in a longitudinal arm of a switching relay, the contact of the switching relay being disposed in a cross-arm in series with a choke coil. The relay operates with a very low voltage drop at the holding winding and occupies a relatively small volume. The circuit can be utilized as an auxiliary relay controlled by means of a delay circuit for selectively cutting in and cutting out the response winding of the relay, particularly in remote feed repeaters or regenerators.

Abstract: An electromagnetic contact device performs on-off operations for opening and closing an electrical path, without causing the hunting phenomenon between the two contact points in the device not only during closure of a fixed contact point and a movable contact point therein, but also when a voltage to be applied to an operating coil has lowered. An operating coil generates a predetermined energizing force in combination with a fixed iron core, a starting circuit rectifies a large capacity electric current from an AC power source when attracting a movable iron core and supplies the rectified current to the operating coil. A holding circuit supplies the large capacity current from the AC power source to the operating coil through means of converting the large capacity current to a small capacity current at the time of holding the movable iron core.

Abstract: A demand controller uses a sensor to detect the operation of an electric load. The sensor operates a relay which supplies power to a magnetic contactor. The magnetic contactor controls power available to a second electric load so that the total amount of power consumed is held below a predetermined maximum. An auxillary switch operates in conjunction with the magnetic contactor to control power available to other loads. A hierarchy is established so that the most important load always has power available, and loads of lesser importance are controlled.

Abstract: A shutdown circuit for a TV projection monitor includes a standby power supply energizing a main power supply through contacts controlled by a relay winding in the load circuit of a control transistor that is cut off by a pair of latch transistors that receive operating power through the relay winding. Closure of a momentary contact switch effectively disables the latch transistors and grounds one end of the relay winding which is thereby energized to enable the main power supply. Disabling the latch transistors permits the control transistor to become conductive and hold the relay winding energized. A subsequent closure of the momentary contact switch applies sufficient potential to the latch transistors to drive them conductive and disables the relay winding for deenergizing the main power supply.

Abstract: A transient over-voltage suppressor circuit for a motor vehicle power supply system that includes a diode-rectified alternating current generator. The suppressor circuit comprises a dual coil relay, a Zener diode and a small resistor having a positive temperature coefficient of resistance. The Zener diode and relay coils are connected across the output terminals of a bridge rectifier connected to the generator and when a transient over-voltage occurs the contacts of the relay are closed. When the relay contacts close they connect the resistor and one of the relay coils across the output terminals of the bridge rectifier. The relay contacts open when the resistance of the resistor increases to a predetermined value.

Abstract: This disclosure relates to methods and apparatus for providing in a tool, appliance, or other electrically operated device the safety feature of requiring that the trigger or ON-OFF switch be in or returned to the OFF position before the tool will respond to placing the trigger or ON-OFF switch in the ON position.

Abstract: A wired program distribution tamper detection circuit useful in CATV including pay T.V. systems which is connected in the subscriber drop cable between the trunk and a subscriber's pay T.V. security device, e.g. descrambler, filter, or converter, or T.V. set and cuts off the program signal in the event the cable is momentarily disconnected as would occur during tampering. The circuit detects an abnormal impedance, in its general form, or the interruption of a d.c. path through the cable, in its preferred embodiment, and inhibits the application of the signal upon such detection. A complaint by the subscriber thus effects an announcement of the tampering.

Abstract: An automatic power reduction circuit having a single silicon controlled rectifier in one leg of a bridge rectifier which is gated off when a capacitor reaches a predetermined voltage level so as to switch automatically the bridge output from a full-wave rectifier to a half-wave rectifier. An auxiliary silicon controlled rectifier is also provided to facilitate the quick discharge of the capacitor so as to reset the circuit to its initial state, thereby allowing fast, repeated operations and preventing malfunctioning upon a loss of power.

Abstract: A hydraulic actuator and valve are used for the control of fuel to a burner. The actuator is energized to open the valve through a manual start switch and a manual reset switch to prevent the manual start switch from being held in either accidentally or intentionally to overcome a safety monitoring control, such as a flame safeguard programmer.

Abstract: A two stage positive shift starter drive system for an internal combustion engine is disclosed. A pair of electrical switches are sequentially actuated by an actuator solenoid engaging the starter drive's pinion gear with the engine's ring gear. The first switch actuated after a predetermined displacement of the solenoid's armature applies electrical power to the cranking motor through a resistance connected in series with the cranking motor and connected in parallel with the solenoid pull-in coil. The resistance reduces the electrical power applied to the cranking motor and the potential across the solenoid pull-in coil thereby reducing the rotational speed and the engagement force applied to the pinion gear. The end of the armature travel closes the second switch applying full power to the cranking motor permitting normal cranking of the engine with the pinion gear fully engaged with the ring gear.

Abstract: Apparatus is disclosed for controlling the operation of electrically operated equipment, such as power tools and the like. The apparatus includes circuit connectors, including first and second spaced terminals, in which the first terminal is connected to a source of electricity and the second terminal is connected to the equipment itself so that electricity can be supplied to the equipment by electrically connecting the spaced terminals.

Abstract: A switching assembly to be incorporated in a window-regulator for a motor vehicle and the like, which includes paired units of switching members, each of which is arranged to serve for operating an electric motor in either of two rotational directions in a manual mode or in an automatic mode subject to the displacing amount of a single switching knob, and an electric circuit means including a solenoid for selectively self-retaining and self-releasing the automatic operating mode. The switching assembly is arranged to be capable of selectively energizing and de-energizing the electric motor incorporated in the window-regulator together with operating the solenoid simultaneously.

Abstract: A control device for a solenoid valve including a valve body provided with a fluid inlet and fluid outlet ports, a valve member provided in the valve body and movable between a closed and open positions and a solenoid coil for electromagnetically actuating the valve member. The control device includes a switching circuit which is adapted to alternatively direct an energizing electric current to the solenoid coil in one direction so that the valve member is moved toward the open position and in the opposite direction so that the valve member is maintained in the closed position. Since the valve member is maintained in the closed position by the electromagnetic force, it is possible to prevent the valve member from being moved out of the closed position even under vibrations to which the valve may be subjected in use.

Abstract: A circuit for turning on the constantly energized loads in a microwave oven in response to the initial energization of the magnetron to begin the cooking operation. The circuit includes a delay start relay having a relay coil and a first normally closed relay switch connected in series with a magnetron switching element across a source to respond to the initial turn-on of the magnetron by the switching element. The relay coil also controls a second normally open relay switch connected to close, in response to energization of the relay, a current path including at least one constantly energized microwave oven load. The second relay switch also closes a holding current path for the relay coil to maintain it in an energized condition during the remainder of the cooking cycle. The first relay switch opens after the second relay switch has closed to electrically isolate the relay coil from the switching device.

Abstract: An apparatus is proposed for controlling the electric current through inductive consumers, in particular through a fuel metering valve in internal combustion engines, this apparatus representing a two-point closed-loop controller and functioning with a single threshold switch for an upper and a lower threshold. The apparatus includes one current-measuring resistor each in the freerunning circuit and in the main current circuit, both measuring resistors being members of a voltage divider between the two supply voltage lines and whose middle junction is carried to the threshold switch. By means of a resistor-diode network in combination with the threshold switch, a correction can be made in the individual switching thresholds in accordance with supply voltage.

Abstract: Comparator means respond to the current levels through an inductive load to generate HIGH and LOW level outputs causing first switch means to connect and disconnect power to the load. When the load current initially exceeds a peak load actuation level, flip-flop means responsive to the corresponding change in comparator output levels change the current through an auxilliary sense resistor coupled to the sense input of the comparator means. In one embodiment, a one-shot multivibrator prevents a change in the current to the auxilliary sense resistor for a fixed period after the commencement of a load actuation signal. The subsequent HIGH and LOW comparator output levels are fed back to the comparator reference input to switch the reference voltage thereat so as to represent first and second levels of the current sufficient to maintain actuation of the load.

Abstract: A control circuit for alternately actuating a pair of loads includes a voltage doubling circuit having a capacitor common to a pair of charge storage devices and switch means which are alternately actuated to discharge the charge storage devices through a pair of loads. Coupled to the circuit is a holding current power supply for maintaining the loads in an actuated position once the charge storage devices are discharged. The circuit thus provides an initially high current pulse for rapidly actuating inductive loads such as solenoids.

Abstract: A catch for a spring loaded hinged lid of a Jack-in-the-box consists of lever, one end of which obstructs an inclined lip on the edge of the lid opposite the hinge. The other end of the lever is held by magnetic attraction to a ferromagnetic plate which is fixed with respect to the box.In the vicinity of the magnet is an electrical solenoid which when pulsed by charge stored in a capacitor produces a magnetic field which opposes the field of the permanent magnet and releases the lever. This in turn releases the lid. When the solenoid is pushed the magnet momentarily releases the plate. Once separated the force of attraction is no longer sufficient to overcome the force exerted on the other end of the lever by the lid spring via the inclined lip.

Abstract: An electrical circuit for allowing electrical power to be applied to the ctro-mechanical sensors of an automatic flight control system of an aircraft only when either the Engine Start switch or AFCS Engage switch is closed separately or simultaneously. Upon the closing of either one or both of the switches, a pair of latching relays are energized which in turn provide electric power to the electro-mechanical sensors.

Abstract: A solenoid-operated fuel valve opens automatically when the engine is started to allow fuel to flow from a fuel tank to the engine and closes automatically when the engine throttle is moved to fuel-off position to shut down flow of fuel through the governor for the engine. In the event of an emergency, operation of a manual shutdown control will de-energize the fuel valve solenoid to shut off flow of fuel to the engine compartment and will also shut down the engine by energizing a solenoid to move the fuel rack for the governor to fuel-off position. Actuation of a fire-extenguisher system for the engine will automatically de-energize the fuel-valve solenoid and energize the fuel-rack solenoid. The fuel-rack solenoid remains energized for a timed period sufficient to ensure engine shutdown in emergency situations.

Abstract: A solenoid control circuit includes a first switching element which connects one side of the solenoid load to earth via a current sensing resistor. The other side of the solenoid load is connected by a second switching element to a supply rail. This second switching element is biased to conduct but can be turned off by either of two comparators which are connected to compare the voltage across the current sensing resistor with two different reference voltages. Each comparator has hysteresis and the circuit operates so that one comparator operates to switch off the second switching element when a predetermined current level is reached and the other comparator operates to switch the second switching elements on and off at lower current levels between said predetermined current level and the lower threshold level of the first comparator.

Abstract: A method for extending the range of operation of an electromagnetic fuel injector for an internal combustion engine employs a technique for reducing the time required for the injector to open while at the same time allowing the injector to maintain a minimum closing time. Prior art techniques have utilized a regulated voltage supply to determine the precise voltage applied to the inductive element of the injector to cause it to open. The present invention does not regulate the applied voltage, but instead the invention allows an unregulated battery or other DC supply voltage to be applied to the inductive element to cause the injector to open as rapidly as possible. The current in the injector is sensed to allow a reduction in the applied voltage when a predetermined maximum current occurs in the inductive element. The voltage reduction permits a holding current to be established in the inductive element to maintain the injector open.

Abstract: An electromagnetic relay comprising an electromagnetic device connectable to a power source, utilized to repel a movable blade and thus separate its movable contact from a fixed contact, driving the blade into another configuration in which it is maintained by a permanent magnet. The current in the energizing circuit of the electromagnetic device flows through the movable contact and through the fixed contact so that when the blade is driven into the second configuration, such energizing circuit is interrupted.

Abstract: A method is proposed for operating an electromagnetic load device with a movable armature, especially an injection valve of an internal combustion engine. The load device is supplied, at the beginning of trigger pulse, with a high amperage current and, at least toward the end of the pulse, with a reduced current. This method is characterized in that, starting with a certain amperage, at which preferably the armature is set into motion but has not as yet reached its final position, the current rise is at least reduced. The apparatus aspect comprises a measuring element and switching element connected in series with the load device. A threshold switch is associated with the measuring element to control the switching element. The switching thresholds of the threshold switch can be controlled in dependence on current and/or on time. The first current threshold is at a value at which the armature of the load is preferably being moved, but has not yet reached its final position.

Abstract: A security device for a fuel such as natural gas having a series circuit of a relay switch, a hazard detecting switch, a relay switch operating coil and a timer. A valve coil is adapted to open and close a main fuel supply valve. The valve coil is connected in parallel to the series circuit. A reset switch is adapted to excite the valve coil and is connected in parallel with the relay switch. In one embodiment, the hazard detecting switch, the relay switch operating coil and the valve coil are coupled through a transformer in series with an electric source. The hazard detecting switch the relay switch operating coil and the valve coil are disposed on a secondary side of the transformer. The main fuel supply valve is normally closed such that in case of a power failure, the valve will close and remain closed.