Abstract: A power switch includes switch contacts that are opened via a switch shaft, which, when the switch is triggered, is actuated by way of the trigger slider of a trigger unit, in particular a working current trigger unit. The trigger slider moves the switch shaft by way of the trigger shaft of a switch latch, the trigger unit including electric coil into which an armature extends that is drawn into the coil by electromagnetic forces of attraction when the switch is triggered. A stationary counter armature is disposed in the coil, which counter armature serves as a stop for the armature, so as to increase the forces of attraction. The movement of the armature is transmitted by way of a mechanism to the movement of the trigger slider so as to increase the displacement path of the trigger slider.

Abstract: A leakage protective plug comprises a case and electric contacts. A protective cap is fixed on the top of the case and includes a reset button protective cap and a test button protective cap. The reset button protective cap is interiorly provided with a reset button connected with a push rod which in order penetrates an electric contact upper panel, an upper spring, an electric contact lower panel and a lower spring. The electric contact upper panel is provided at a right side thereof with a locking member linked with a brake connecting rod which is linked with a brake plate. The brake plate is located at a lower right side of the locking member. Below the brake plate are disposed an electromagnet pole shoe, an electromagnet coil, and an electromagnet core. The test button protective cap is provided with a test button having a test electric contact.

Abstract: A polar electromagnet device has a drive shaft comprising an axis center supported so as to reciprocate in an axis center direction at a center hole of a spool wound with a coil, and a movable iron core attached to a lower end of the drive shaft on the axis center. The drive shaft is reciprocated with the movable iron core which reciprocates based on excitation and demagnetization of the coil. A permanent magnet is integrally arranged at the movable iron core on the same axis center.

Abstract: An electromagnetic switch includes an electromagnetic coil, a fixed core, a movable core, and a diode. The electromagnetic coil is configured to form an electromagnet when energized. The fixed core is arranged to be magnetized by the electromagnet. The movable core is arranged to be attracted by the magnetized fixed core to move in a movement direction toward the fixed core. The diode is electrically connected in parallel with the electromagnetic coil. The diode includes a main body and has a pair of leads respectively extending from a pair of ends of the main body which are opposite to each other in a lead arrangement direction of the diode. The lead arrangement direction of the diode is parallel to the movement direction of the movable contact.

Abstract: A disconnect mechanism for a power receptacle, which includes a disconnect block, a locking member slidably coupled to the disconnect block, and an electromagnetic device moveably coupled to the locking member. The disconnect block includes two side arms extending outwards. A pressing plate is disposed above the disconnect block, and a disconnect spring is disposed above the pressing plate. The moveable contact arms of the main switch of the receptacle are disposed between the pressing plate and the disconnect block, and the pressing plate pushes the moveable contact arms when the main switch is being opened when a current leakage is detected. The receptacle also includes an auxiliary switch disposed because the disconnect block and the circuit board.

Abstract: An electromagnetic switching device includes: a housing; first contacts coupled to the housing; a second contact which is brought into contact with the first contacts and separated from the first contacts; and an actuator for driving the second contact such that the second contact is brought into contact with the first contacts and separated from the first contacts, wherein any one of the first contacts and the second contact includes an elastic deformation portion elastically deformed when the first contacts and the second contact are brought into contact. Vibration and noise generated when contacts are brought into contact can be suppressed.

Abstract: An electromagnetic switching device including: a housing; fixed contacts disposed in the housing; a movable contact which is brought into contact with the fixed contacts and separated from the fixed contacts; and a driving unit disposed at one side of the housing and driving the movable contact, wherein the fixed contacts are disposed to be perpendicular to a direction in which the movable contact moves. Thus, noise generation can be suppressed and external size can be reduced.

Abstract: An installation switching device having at least one pole current path comprises two stationary contact pieces; a moving contact bridge including two moving contact pieces forming a double-break pole with the two stationary contact pieces; a contact pressure spring exerting a pressure on the moving contact bridge in a closing direction of the moving contact bridge; a pusher configured to act on the moving contact bridge counter to the pressure of the contact pressure spring in an opening direction, the pusher including a slide and a striking pin disposed moveably relative to the moving contact bridge and to one another in a movement direction of the moving contact bridge; a switch latch having a latching point; an operating lever configured to act on the pusher; and an electromagnetic release having an impact armature.

Abstract: A contact device has a first yoke having a substantially U-shape, a second yoke bridged over both ends of the first yoke, a spool wound with a coil disposed between the first yoke and the second yoke, a movable iron core inserted into a center hole of the spool in a reciprocating mariner, and a contact mechanism unit formed above the second yoke driven with a drive shaft having a lower end fixed to the movable iron core, which reciprocates based on excitation and demagnetization of the coil, and an upper end projecting out from an upper surface of the second yoke. An insertion hole communicating to the center hole of the spool and through which the movable iron core reciprocates is formed in the first yoke. An annular auxiliary yoke including an insertion hole communicating to the insertion hole of the first yoke and through which the movable iron core reciprocates is provided at a lower surface of the first yoke.

Abstract: An electromagnetic relay has a movable contact arranged at one end of a drive shaft that reciprocates in an axis center direction based on excitation and demagnetization of an electromagnet block, and a pair of adjacently arranged fixed contacts with which the movable contact is operable to contact and separate. A first electromagnetic iron piece, a second electromagnetic iron piece and the movable contact are inserted to the drive shaft so that the first electromagnetic iron piece and the second electromagnetic iron piece sandwich the movable contact. The second electromagnetic iron piece is biased to one end side of the drive shaft with a coil spring inserted to the drive shaft. When the movable contact contacts to the pair of fixed contacts, the second electromagnetic iron piece forming a magnetic circuit with the first electromagnetic iron piece pushes the movable contact to the pair of fixed contacts.

Abstract: A circuit breaker and method includes a mechanical pole moveable between a latched position and an unlatched position to open an electrical connection between a pair of electrical contacts. An electronic tripping device is configured to respond to a sensor signal. The sensor signal is output from a condition sensor wherein upon receiving the sensor signal the electronic tripping device trips the mechanical pole into the unlatched position.

Abstract: An electromagnetic contact device has a contactor holder (40), which moves a mounted movable contactor (42a) according to a displacement of a movable core (32) forming an electromagnet (30) for operation. The contactor holder (40) is being housed together with the electromagnet (30) for operation in a case (1). The case (1) has a lower case portion (10) housing the electromagnet (30) for operation and an upper case portion (20) engaging with the lower case portion (10) while being stacked on the lower case portion and houses the contactor holder (40) advanced from above. The upper case portion (20) has a recess (21) with an upward opening and houses the contactor holder (40) placed on the bottom wall of the recess (21). The lower case portion (10) houses one selected either a DC-only electromagnet (30b) or an AC-only electromagnet (30a).

Abstract: A sealed contact device has a plate-like yoke having a center hole therein, a closed-ended cylinder having an opening edge portion that is integrated with a lower-surface edge portion of the center hole of the plate-like yoke to form a sealed space, an annular flange having an outer peripheral edge portion that is integrally welded to an upper surface of the plate-like yoke, a ceramic case having a lower end surface that is brazed to an upper surface of the annular flange, an electromagnetic unit disposed in an outer periphery of the closed-ended cylinder, a movable iron core that reciprocates in the closed-ended cylinder based on excitation and demagnetization of the electromagnetic unit, a movable shaft having a first end fixed to the movable iron core, a movable contact of a movable touch piece fixed to a second end of the movable shaft, a fixed contact disposed in the ceramic case, and an annular rib projected in the upper surface of the annular flange such that the brazed portion provided in the lower en

Abstract: A multi-pole circuit breaker and method include at least two breaker modules including circuit breakers therein. The circuit breakers include a moveable arm configured to connect and disconnect contacts therein. The at least two modules including armatures connectable to the moveable arms of each of the at least two modules. A center module connects the at least two modules. The center module includes an actuator and a beam connected to the actuator at a mid-portion. The beam connects to each armature of the at least two modules wherein under a trip condition the actuator displaces the beam to simultaneously trip the at least two modules using the armatures.

Abstract: An actuator comprising: a fixed part comprising a ferromagnetic yoke and a magnetized assembly mounted on a face of the yoke and extending substantially over the whole dimension of said face parallel to the axis of movement of a moving part, the moving part comprising a ferromagnetic element comprising a first air-gap surface to form a magnetic air-gap of variable thickness and a second air-gap surface parallel to the axis of movement to form a residual magnetic air-gap of constant thickness with a corresponding air-gap surface of the magnetized assembly. an excitation coil. An electric switch apparatus equipped with the actuator.

Abstract: An apparatus for auxiliary contact of circuit breaker is disclosed that is capable of preventing an erroneous operation of and damage to an ON/OFF switch caused by over-stroke of a linkage mounted at an auxiliary contact apparatus, and enhancing reliability despite repeated opening/closing thereof.

Abstract: The present invention provides a switch suitable for efficient microfabrication. The switch elements are disposed in several layers. Various embodiments provide various switching capabilities and operational characteristics. The switches can be protected by suitable packaging, and can be efficiently fabricated in groups or arrays.

Abstract: An electromagnetic relay, includes a fixing contact; a movable contact configured to be moved to or from the fixing contact in an approaching and separating direction; a movable part; a driving part configured to drive the movable part; a pressing part configured to press the movable contact based on the driving of the movable part; and a magnetic body provided at an external periphery side of at least one of the fixing contact, the movable contact, and an air space in the approaching and separating direction of the fixing contact and the movable contact.

Abstract: A relay includes a contact point block having a support shaft with both ends spanning a contact point base, a plunger having a movable contact at a lower end thereof, and a movable iron piece configured to drive the plunger and to have a plate spring. The relay also includes an electromagnetic unit and a base block having a fixed contact point at a position opposite to the movable contact point. The movable iron piece is supported on the supporting shaft. The plunger is inserted through an operation hole of the contact point base. Upper and lower surfaces of the contact point block are held by the electromagnetic unit and the base block. The electromagnetic unit directly fixes the iron core to an upper surface of the contact point base.

Abstract: A hermetically sealed relay is provided having two circuits therein.

Abstract: A bypass device for bypassing a power cell of a multi-cell device. The bypass device includes a stationary portion of a first set of contacts connected to at least first and second output terminals of a power cell, a magnetically latching solenoid that, when energized, moves a moving portion of the first set of contacts from a first position to a second position or from the second position to the first position, and at least one added insulating material positioned between the solenoid and the first set of contacts, and configured to allow a voltage between the magnetically latching solenoid and the first and second output terminals of the power cell to exceed a voltage between said output terminals.

Abstract: An improved electromechanical switch designed to operate at frequencies from DC through microwave has terminal probe tips that are formed from an alloy of noble metal and contoured with a pattern of peaks and valleys in order to provide better contact wiping operation and capture of wear debris. The switch incorporates damper elements to reduce switching contact bounce, thus providing increased contact life as well as higher quality signal switching.

Abstract: An electromagnetic contactor has a stationary core; a coil arranged around the stationary core; a movable holder movable toward the stationary core; a movable core coupled to one end of the movable holder for being attracted to the stationary core by the excitation of the coil; and a nonmagnetic structural component arranged on the movable core facing the stationary core. The nonmagnetic structural component is a flat plate structural component with high flexural rigidity, overlaid on the surface of the movable core to face the stationary core. The nonmagnetic structural component and the movable core are held between a cushioning spring and a coupling pin. The cushioning spring is contained in the movable holder and buts the back face of the movable core not facing the stationary core. The coupling pin crosses the nonmagnetic structural component with both ends engaged with a pair of holder legs.

Abstract: Provided are a standby power cut-off device for automatically cutting off standby power according to power-on/off of an electronic product and a control method for the standby power cut-off device. By providing an electronic product to which the standby power cut-off device and the control method therefor are applied, the present invention can efficiently cut off standby power by using an existing general outlet without a need to use an outlet having a separate function added thereto. Moreover, the present invention automatically cuts off the standby power according to power-off of the electronic product without unplugging the electronic product, thereby maximizing user's convenience.

Abstract: A method and a device are disclosed for the secure operation of a switching device including at least two main contacts which can be switched on and off and which includes respectively, contact pieces and a displaceable contact bridge, and at least one control magnet which includes a displaceable anchor. The anchor acts upon the contact bridge when it is switched on and off such that the corresponding main contact is opened or closed. At least one embodiment of the inventive method includes the following steps: a) release device for a force element remains in a first state in order to interrupt the main contact as long as the main contacts are closed when switched on and open when switched off, and b) the release device are transferred into a second state if at least the main contact is welded after switching off.

Abstract: A drive device has a rotatable driving shaft and a driven shaft. The driving shaft, or input shaft, and the driven shaft, or output shaft, are joined to each other by way of a magnetic coupling. The driven shaft can be blocked in a direction of rotation such that magnetic forces emanating from the magnetic coupling cause the driven shaft to move in a direction opposite that of the direction of blocking. The driven shaft moves in a springing manner.

Abstract: An electrical contactor includes a moveable core member having a first moveable core surface and a second movable core surface. The second moveable core surface is angled relative to the first moveable core surface. A stationary core member is mounted relative to the moveable core member. The stationary core member includes a pole arm having a first stationary core surface and a second stationary core surface. The second stationary core surface is angled relative to the first stationary core surface. In response to a magnetic field traversing a path defined by the stationary core member and the moveable core member, the first stationary core surface is magnetically biased to mate with the first moveable core surface and the second stationary core surface is magnetically biased to mate with the second moveable core surface to bring into contact an electrical contact member and an electrical contact element.

Abstract: There is provided an electromagnetic switch, for a starter, that is capable of preventing a defect caused by the formation of a leakage circuit between the battery terminal and the motor terminal, even in the case where the electromagnetic switch is flooded with water. On the outer surface of a switch cap, there is provided a diaphragm disposed between the battery terminal and the motor terminal that are arranged in such a way as to be exposed outside the switch cap; the diaphragm is formed in such a way that a wall face thereof that faces one terminal, out of the battery terminal and the motor terminal, which is disposed upper than the other terminal has a protrusive shape.

Abstract: An electromagnetic relay has an overtravel adjustment to set the gap in the contact arrangement. The armature is actuated by a relay coil and linked to a pusher to drive the pusher to operate the contact system. The pusher includes a rotary dial disposed in a slot on the pusher adjacent to the armature. The rotary adjustment increases or decreases a gap of the contacts to provide an over-travel adjustment. The pusher includes bifurcated tines defining the slot for receiving an armature linkage and the rotary adjustment. The rotary adjustment includes a head and a post depending from the head. The post is disposed within the slot and the head portion in contact with the armature linkage portion. The rotary adjustment sets the distance between the forward edge and the armature to achieve the desired overtravel for the contact arrangement.

Abstract: A switching device for selectively switching electrical power from an electrical power source to a load circuit comprises a housing. An electromechanical actuator is in the housing. A fixed contact is fixedly mounted in the housing. A contact arm is pivotally mounted in the housing. The contact arm carries a movable contact and has a lever. The contact arm is operatively connected to the actuator to be selectively positioned thereby for selectively electrically contacting the moveable contact with the fixed contact. A rotational actuator is rotationally mounted to the housing. The rotational actuator includes a leg proximate the lever so that rotational movement of the rotational actuator pivotally moves the contact arm to override the electromechanical actuator.

Abstract: A remote operation includes an electromagnetic linear actuator that has a moving part linked to a handle of a circuit breaker, and drives the handle according to a remote operation command to perform change-over operations on the handle to ON, OFF, and RESET positions. The electromagnetic linear actuator is composed of permanent magnet type linear pulse motors each including a field section having a plurality of permanent magnets arranged in a row and a coil section having a three-leg type magnetic yoke and actuation coils wound around the legs of the magnetic yoke and opposing the field section. Electric current in the actuation coils is controlled by sequentially changing-over excitation patterns during the operation process, and the moving part is driven in a stepwise motion to drive the handle of the circuit breaker to the end position of the changeover operation process.

Abstract: Magnetically latching and releasing a voice coil actuator for controlling electrical switchgear. The voice coil actuator includes a voice coil magnet disposed on a common longitudinal axis with respect to a voice coil assembly. A coil of the voice coil assembly exerts a magnetic force on the voice coil assembly, thrusting the voice coil assembly towards the voice coil magnet. At least one pair of latching members mounted to the voice coil assembly creates a permanent magnet circuit between the latching members and the voice coil magnet. The permanent magnet circuit maintains the position of the voice coil assembly relative to the voice coil magnet, even when power to the coil is removed. This latch can be released by applying a current in the coil or by applying an external, physical force to a member coupled to the voice coil assembly.

Abstract: An electromagnetic relay enables current to pass through switch termini and comprises a coil assembly, a rotor or bridge assembly, and opposing, balanced switch assemblies. The coil assembly comprises a coil and a C-shaped core. The coil is wound round a coil axis extending through the core. The core comprises core termini parallel to the coil axis. The bridge assembly comprises a bridge and a pair of actuators. The bridge comprises medial, lateral, and transverse field pathways. The actuators extend laterally from the lateral field pathway. The core termini are coplanar with the axis of rotation and received intermediate the medial and lateral field pathways. The actuators are cooperable with the switch assemblies. The coil creates a magnetic field directable through the bridge assembly via the core termini for imparting bridge rotation about the axis of rotation. The bridge rotation displaces the actuators for opening and closing the switch assemblies.

Abstract: A core for an electromagnetic device includes a yoke and at least two legs extending from the yoke. The yoke and at least two legs are formed of steel plates laminated together. Each of the legs has a free end face forming a magnetic pole face, a first groove extending from the magnetic pole face and a second magnetic groove on a side face thereof. Also, the core includes a shading coil having a metal ring shape, and including a first linear section and a second linear section extending in parallel with each other. A part of the first linear section is accommodated in the first groove, and a part of the second linear section is accommodated in the second groove and locked therein. A bottom face of the second groove forms an angle with respect to a bottom face of the first groove.

Abstract: An electrical switch for connecting and breaking a circuit including a connecting and breaking mechanism for connecting and breaking the circuit provided with at least a set of movable contacts and stationary contacts; a electromagnetism drive mechanism for controlling the contacts to be actuated so as to realize closed circuit; a housing for accommodating the movable contact and stationary contact; an arc-extinguishing mechanism disposed in the housing and corresponded to the movable and stationary contact; a case connected to a base for accommodating the electromagnetism drive mechanism; a bedplate associated with the case; and a holding mechanism disposed on the bedplate for holding the contacts to connect the circuit, the electromagnetic holding mechanism is electromagnetic and has a set of electromagnetic attracting mechanism in which the movable iron core is made to be a pothook or a baffle mechanism, the movable iron core is attracted so that the pothook or baffle keeps the switch closed by means of hi

Abstract: A switching contact, an electromagnetically operated electromagnet for driving the switching contact, and a drive power source device for driving the electromagnetically operated electromagnet. The electromagnetically operated electromagnet includes a movable core coupled to a movable contact of the switching contact, a fixed core located in a peripheral portion of the movable core, and coils wound around the movable core and the fixed core. Currents are supplied to the coils to drive the movable core. Capacitors store charges for supplying the current to the coils. Resistors are arranged in series with a path through which the capacitors are connected with the coils of the electromagnetically operated electromagnet and through which a current for closing operation flows. Capacitances of the capacitors and values of the resistors are controlled to adjust a supplied current characteristic to the electromagnetically operated electromagnet.

Abstract: An electromechanical switching device, especially a contactor or a multifunctional device including a contactor, includes at least one stationary contact piece, at least one movable contact piece movable to and from the at least one stationary contact piece for opening or closing a current path and an electromagnetic drive unit including a yoke and a coil and a movable armature. In at least one embodiment, the electromagnetic drive unit is adapted to displace the movable contact piece in response to a voltage applied to the coil. The at least one movable contact piece and the at least one stationary contact piece are adapted to limit movement of the armature after activation of the electromagnetic drive unit.

Abstract: An electromagnetic switch for use in actuating a starter for automotive vehicles is provided. The switch includes fixed contacts, a moving contact, and a plunger shaft. The moving contact is joined to a plunger shaft through an insulator. The plunger shaft is to be moved magnetically to bring the moving contact into abutment with the fixed contact to establish electric communication between the fixed contact. The switch also includes a rotation holder working to hold the moving contact and the insulator from rotating relative to each other. Use of the rotation holder results in a decrease in wear of the insulator. This eliminates the need for the insulator to have an additional thickness which would be worn down, thus permitting the insulator to be reduced in thickness to shorten the overall length of the switch.

Abstract: A relay includes a magnetic system provided with an armature and a contact system provided with a first contact and a moveable second contact. An electrically insulating base plate is arranged between the magnetic system and the contact system and has an opening therein. First and second walls extend from the base plate and are arranged between the opening and the magnetic system or the opening and the contact system. An actuator extends between the armature and the contact system through the opening and transfers movement of the armature to the second contact to move the second contact into electrical engagement with the first contact. The actuator has a third wall that extends toward the base plate and between the first and second walls. The first, second, and third walls extend a leakage path of an electrical leakage current between the contact system and the magnetic system.

Abstract: An actuator comprising: a fixed part comprising a ferromagnetic yoke and a magnetized assembly mounted on a face of the yoke and extending substantially over the whole dimension of said face parallel to the axis of movement of a moving part, the moving part comprising a ferromagnetic element comprising a first air-gap surface to form a magnetic air-gap of variable thickness and a second air-gap surface parallel to the axis of movement to form a residual magnetic air-gap of constant thickness with a corresponding air-gap surface of the magnetized assembly. an excitation coil. An electric switch apparatus equipped with the actuator.

Abstract: A switching apparatus and method, the apparatus comprising a relay including a relay coil and at least one normally open relay contactor that closes when the relay coil is energized, a normally closed stop contactor and a stop member moveable between a deactivated position in which the stop contactor is closed and an activated position wherein the stop member forces each of the stop contactor and the relay contactor open.

Abstract: Multipole circuit breaker comprising single-pole breaking units in the form of cases with two large side faces and having at least one movable contact which operates in conjunction with at least one stationary contact, an operating mechanism common to a set of breaking units to command opening or closing of the contacts of said units, first line-side electrical connection means, second load-side electrical connection means; the breaking units are grouped on two superposed layers, at least one layer comprising at least one pair of units, the operating mechanism comprising mechanical connecting means to simultaneously actuate the single-pole breaking units of each layer.

Abstract: A simple and low-cost electronic function relay is specified, for example an overload relay with a bistable printed circuit board relay module. The relay includes an engagement point for mechanical operation. The relay further includes a separate reset mechanism, which can be coupled to the printed circuit board relay module, and a switching lever, which corresponds with the engagement point, for manual resetting of the printed circuit board relay module to a switched-on position.

Abstract: Switching device comprising a contact block having a fixed part connected to at least one electric terminal and having at least one electric contact zone able to be in contact with a contact zone of a movable part, an actuating device enabling the movable part to be moved from a closed position to an open position of said contact zones. The fixed part comprises two bases. The actuating device is formed by at least one electric coil placed between the bases. The movable part comprises a magnet able to move between two stable positions. The magnet comprises an electric contact zone electrically connected to a first electric terminal and able to be electrically in contact with contact zones connected to a second electric terminal.

Abstract: A system and method for resetting a tripped circuit breaker are provided. The system includes a monitoring mechanism for monitoring a state of at least one electrical circuit breaker and for generating at least one monitoring signal indicative of the state of the at least one electrical circuit breaker; an actuating mechanism for actuating the at least one electrical circuit breaker in a plurality of positions; and a controller for receiving the at least one monitoring signal and for generating and transmitting at least one control signal to the actuating mechanism for resetting the at least one circuit breaker. The breaker reset system is self-contained and dimensioned as an add-on component to previously installed circuit breaker enclosure or as an integrated component of a circuit breaker enclosure. Additionally, the system allows for manual over-ride of the reset function.

Abstract: A high-temperature shutdown protecting relay comprises a base; a L copper pin and a N copper pin are provided on the base with resting contacts provided at their bottoms respectively; stretchy copper blades are provided on the base, which are fit to the L copper pin and the N copper pin respectively, with movable contacts provided thereon, which are fit to said resting contacts; a stand is provided on the base and above the stretchy copper blades; grooves are provided on the lower side of the stand with ceramic rods for insulating the stand from the stretchy copper blades embedded therein. The high-temperature shutdown protecting relay provided by the present utility model can keep normal operating property under high temperature.

Abstract: A switching device includes a latching mechanism and is cheap to produce and easy to assemble. To this end, the construction is essentially formed from a three-part modular unit including metallic material, and has a spring which supports the back-latching of the latching mechanism, and forces which extend essentially in one plane in the latching mechanism.

Abstract: An operating mechanism assembly for a circuit breaker that includes a frame assembly, a metal pivot structure, and a trip device. The trip device has a cradle member structured to pivot about a pivot point and a trip assembly. The trip assembly is coupled to the frame assembly. The cradle member is pivotally disposed on the metal pivot structure.

Abstract: The aim of the invention is to protect an electromagnet switching device when a load is switched to a supply voltage. A current that flows through the load contact is monitored. The electric circuit is interrupted when the current exceeds a threshold value that is below the current carrying capacity of the load contact. The electric circuit is automatically closed again after the current which flows through the load contact has decreased.

Abstract: An electromagnetic switch includes a contact holding member connected to a plunger in order to hold a first movable contact. The contact holding member is disposed outside a switch case covering a periphery of an excitation coil. A return spring pushes the plunger back in the opposite direction to a fixed iron core through the contact holding member when electric power supply to the excitation coil is stopped. The return spring is disposed outside the switch case. In this structure, a spring holding portion does not need to be disposed in the fixed iron core and the plunger. Therefore, an area where the fixed iron core attracts the plunger can be increased, so that an attraction force can be increased.