40 results about "Open contact" patented technology

The utility model discloses a control system for soft start of a motor in the papermaking industry, which comprises a soft starter RQ, a terminal 7 and a terminal 10 of the soft starter RQ are in short circuit, a terminal 8 and a terminal 9 of the soft starter RQ are in short circuit, the terminal 8 and the terminal 9 of the soft starter RQ are both connected with one end of a normally open contact of a relay KA, and the other end of the normally open contact of the relay KA is connected with the terminal 7 and the terminal 10; and the terminals L11, L12 and L13 of the soft starter RQ are connected with one end of a contact of a contactor 2KM, and the other end of the contact of the contactor 2KM is connected with a motor M. The soft starter has the following advantages that the motor can continuously operate under the condition that the soft starter misreports a fault, and after the fault is misreported, the motor can still continuously operate and has circuit break protection, so that the condition that components are damaged cannot occur.

Provided is a two-degree-of-freedom ring frame repeated locking and circuit automatic switching gyro locking mechanism, which belongs to the technical field of inertial devices and comprises a shell, a shell cover arranged on the shell, an inner ring and an outer ring arranged in the shell, a limiting cam arranged on the inner ring, a locking pin elastically supported on the outer ring, and a locking cam arranged outside the outer ring; an electromagnet assembly is fixed on the shell cover, a torsional spring arm is installed in a U-shaped groove of the electromagnet assembly, an axle is positioned and installed through the torsional spring and a support arm hole to make the support arm generate a fixed shaft torque, an armature is installed in a hole of the electromagnet assembly, the armature is connected with the support arm through a pull rod, a pulley assembly and a limiting groove shaft are respectively riveted on a support arm bending space face positioning hole and are respectively used for precisely positioning the locking cam and the locking pin on the outer ring; the shell cover is symmetrically provided with two sides of an axis, and a normally open contact and a normally closed contact are respectively installed at an angle of 60° between the two sides. The gyro locking mechanism can realize the functions of gyro repeated locking reset, automatic switching and output of electric signals, and meets the requirements of automatic driving of a missile body.

The application discloses an OBD extension connecting line, which comprises a joint assembly, a switching circuit assembly, a circuit assembly and an extension assembly, the joint assembly comprises a male joint body, one side of the male joint body is fixedly connected with a trapezoidal socket, and a plurality of metal columns are embeddedly connected in the male joint body. The male joint body in the joint assembly is connected with the whole circuit of the device, a plurality of metal columns are arranged in the male joint body, the metal columns are connected with signals and main power supply, the main power supply is connected with the main power supply circuit through the contact metal wire, the main power supply circuit is connected with the first normally open contact and the second normally open contact, the first normally open contact and the second normally open contact are connected with the circuit connecting coil, the main power supply supplies power, the first normally open contact and the second normally open contact are adsorbed through the coil, the general power circuit is connected, when the main power supply is insufficient, the coil works, the first normally closed contact and the second normally closed contact are closed, and the auxiliary power supply is connected with the power circuit.

The application discloses an insulation protection structure and an electromagnetic relay, and relates to the technical field of electromagnetic relays. The application comprises an insulator, an installation cavity is formed in the insulator, a partition plate is arranged in the installation cavity, and an insulating sleeve is fixed to one side of the partition plate. The application separates the enameled coil from the normally open contact, the normally closed contact and the movable contact in another cavity by adopting the cooperation design of the insulating sleeve, the movable plate and the driving plate, and then when the enameled coil is powered off, the iron core stops adsorbing the magnetic adsorption plate, and the driving plate is reset under the action of the first torsional spring, the movable plate can be driven to slide to separate the movable contact from the normally open contact, and then the blocking assembly can be driven to move by the movable plate to block the electric arc between the normally open contact and the movable contact. Compared with the prior art, the application can solve the safety hazards of the discharge creeping of the electromagnetic relay and the safety hazards of the arc drawing of the electromagnetic relay.

The application discloses a socket power supply device and a connecting method which can prevent live plug-in and belongs to the technical field of design and manufacture of high-power load power supply socket. The socket power supply device comprises a power supply socket box, a plug and an electric machine. The connecting method which can prevent live plug-in comprises the following steps. The method for preventing the plug from being pulled out of the socket with electricity comprises the following steps: S11, unbuckling the buckle and providing external force to the plug to pull it out of the socket; S12, stroke impact rod is reset through a spring, the normally open contact of a micro switch is disconnected, and a power supply breaker is automatically tripped. The method for preventing the plug from being inserted into the socket with electricity comprises the following steps: S21, when the plug is not inserted into the socket, the normally open contact of the micro switch is disconnected, and the power supply breaker cannot be tripped; S22, providing external force to the plug to insert it into the socket and buckling the buckle; S23, stroke impact rod touches the micro switch, and the power supply breaker is normally tripped. The application can effectively prevent the problem of spark generated by live plug-in of the socket and increase the safety coefficient.

The utility model discloses a motor protection circuit and ventilation equipment, which are characterized in that a first power supply input end is connected with a normally open contact of a first relay and a first end of a coil, a second power supply input end is connected with a normally closed contact of the first relay, and a third power supply input end is connected with a second end of the coil; therefore, when the first power supply input end, the second power supply input end and the third power supply input end receive abnormal power supply input signals, the first optocoupler, the second optocoupler, the first triode, the second triode, the third triode or the fourth triode can be controlled to be switched on and off through the relay. According to the invention, damage to the motor caused by wrong connection of the power supply can be avoided, the operation safety of the motor is improved, and the service life of the motor is prolonged.

The utility model belongs to the technical field of brake switches of electric forklifts, and particularly relates to a novel double-contact brake switch which is mainly composed of a pressing rod, a mounting shell, a contact brake assembly, an upper protective shell, a lower protective shell, a T-shaped screw, a locking nut and the like. According to the utility model, through the arrangement of the contact braking assembly, under the pressing action of the pressing rod, the normally-closed contact of the contact braking assembly is switched off, and the normally-open contact is switched on; under the pressing action of the pressing rod, a normally-closed contact of the contact braking assembly is closed and a normally-open contact of the contact braking assembly is opened under the reset action of the reset spring, so that contact braking of the braking switch is realized; besides, two groups of normally-closed contacts and two groups of normally-open contacts are respectively arranged, so that the contact of the contacts is ensured, and the condition of brake failure caused by the fact that the contacts cannot be contacted is avoided.

This invention provides a multi-detection access control system for energy storage containers, including a detection device. Each container door is equipped with a mechanical limit switch. When the door is closed, the normally open contact of the corresponding mechanical limit switch is open, and the normally closed contact is closed. When the door is open, the normally open contact of the corresponding mechanical limit switch is closed, and the normally closed contact is open. The normally open contacts of each mechanical limit switch are connected in series and form a circuit with the coil of a first relay and a first battery. The normally closed contacts of each mechanical limit switch are connected in parallel and form a circuit with the coil of a second relay and a second battery. The first and second relays are connected in parallel and are both connected in series between the first and second signal input terminals of the detection device. The detection device determines the door status based on whether there is continuity between the first and second signal input terminals. This invention ensures accurate and reliable reporting of access control signals and reduces the risk of missed detections.

The utility model relates to the technical field of temperature controllers, in particular to a temperature controller capable of monitoring forward and reverse plugging of a plug. According to the utility model, when the circuit is positively connected, the normally open contact of the first relay is closed, the first indicating lamp is electrified, and the positively connected signal input end of the control panel receives a high-level signal, so that related personnel can conveniently carry out subsequent program design; the current flowing through the circuit is extremely small and is equivalent to a high-resistance resistor, at the moment, the piezoresistor is equivalent to a disconnected switch, the first indicator lamp cannot be powered on, and the positive connection signal input end of the control panel cannot receive a high-level signal, so that related personnel can conveniently carry out subsequent program design, and then monitoring of positive and negative plugging of the plug is realized; positive and negative plugging of the plug can be monitored under the condition that the circuit is not short-circuited, and related prompts can be given.

The invention relates to a CT automatic short circuit open circuit prevention contact structure, and belongs to the technical field of power system testing devices, the CT automatic short circuit open circuit prevention contact structure comprises a first reed, a second reed, at least one third reed and at least one fourth reed, the first reed comprises a first contact part, a second contact part, a third contact part and a connecting part, the second contact part and the third contact part are arranged on the connecting part, the second reed comprises a fourth contact part, the third reed comprises a fifth contact part and a sixth contact part, and the fourth reed comprises a seventh contact part; the first contact part, the second contact part and the fourth contact part are arranged in the same row of the socket; each third contact part corresponds to one third reed and one fourth reed, and the corresponding third contact part, third reed and fourth reed are located in the same row; the internal structure of the test socket is simplified, the assembly efficiency is improved, the number of conductive connection points is reduced, and the conductive reliability is improved.

This utility model relates to the field of micro switch technology and discloses a novel tension spring micro switch, including a base. A slot is provided in the middle of the base, which engages with the right side of a movable bracket. A movable contact component is located above the movable bracket and is connected to the upper part of the movable bracket via a tension spring. A sliding groove is provided on the upper left side of the base, through which a button that cooperates with the movable bracket is slidably connected. Normally closed and normally open contact components, respectively, are located on the upper and lower sides of the right end of the movable contact component and engage with the base. A support foot is provided at the bottom of the base, with one side of the support foot located inside the base and connected to the left side of the movable contact component. This utility model applies to a novel tension spring micro switch, using a tension spring to connect the movable bracket and the movable contact component. The fulcrum of the movable bracket is located on the right side of the base, significantly increasing the switch lever arm length and ensuring contact pressure at the switch contacts while achieving the light pressure requirement of the overall switch.

The utility model relates to the field of microswitch, the utility model discloses a waterproof microswitch, include: casing, insulating button and pin subassembly, the lower end side of insulating button is equipped with trigger part, and the trigger part includes the trigger recess and non-trigger area that set gradually from top to bottom, and the pin subassembly includes common contact, normally closed contact and normally open contact, and the upper end of normally closed contact and normally open contact is equipped with normally closed contact point and normally open contact point respectively, and the upper end of common contact is equipped with elastic end, and the lower end of elastic end extends the setting along the direction of away from insulating button, and the one end of elastic end close to insulating button is abutted in trigger part, and the one end of elastic end away from insulating button is equipped with common contact point, and common contact point sets up between normally closed contact point and normally open contact point, when elastic end abuts at non-trigger area, common contact point abuts at normally closed contact point, when elastic end abuts in trigger recess inner wall, common contact point abuts at normally open contact point. Improved waterproof performance, prolongs the life.

The invention provides a laser protection circuit, and relates to the technical field of laser driving and safety protection. The protection circuit is arranged between a laser driver and a laser, and comprises a first interface connected with the laser driver; the first interface is provided with a first pin; the second interface is connected with the laser; the second interface is provided with a second pin; the relay array module comprises a double-pole double-throw relay with a common contact, a normally open contact and a normally closed contact; wherein the common contact is connected to the second pin; the normally open contact is connected to the first pin; the normally closed contact is connected to a grounding point; when the relay array module is in a power-off state, the common contact and the normally-closed contact are conducted, and the second pin is connected to the grounding point.

The application discloses an electromagnetic relay with reduced occupied space, comprising a base, a magnetic circuit part and a contact part, the contact part comprising at least one normally open contact group and at least one normally closed contact group, the normally open contact group and the normally closed contact group each comprising a dynamic spring part and a static spring part matched with each other, the dynamic spring part comprising a dynamic spring sheet and a dynamic contact; the normally open contact group and the normally closed contact group are arranged along a horizontal first direction on the base, and the free end of each dynamic spring sheet is respectively provided with a dynamic contact; the free end of the dynamic spring sheet of the normally open contact group and the free end of the dynamic spring sheet of the normally closed contact group are towards different sides of a second direction perpendicular to the first direction, and the dynamic spring sheet of the normally open contact group is inclined to extend to the direction of disconnecting the contact, and / or the dynamic spring sheet of the normally closed contact group is inclined to extend to the direction of closing the contact. The contact groups are more compact, and the occupied space of the product in the first direction is reduced.

The utility model provides a switch test circuit and device. The switch test circuit comprises an input port, a leakage protector, a first fuse, a contactor contact switch, a transformer and a second fuse. The output end of the input port is sequentially connected with the leakage protector, the normally open contact switch, the transformer and the output port in series; a first fuse is connected in series between the leakage protector and the normally open contact switch; a second fuse is arranged between the transformer and the output port; and a control circuit is connected in parallel between the first fuse and the contactor contact switch. During use, a secondary test wire of a transformer of tested equipment is removed and connected with an output port, so that the equipment can be comprehensively detected by using safety voltage, including closing, opening, near and remote control, short circuit test, electric leakage test, comprehensive protector test, parameter modification, power-on test of part of components and maintenance of a control circuit. Through the switch test circuit, maintenance difficulty and time can be reduced, and personal and equipment safety can be guaranteed.

This application relates to the field of circuit changeover switch technology, specifically a dual-redundant arc-shaped contact limit switch, comprising: a base, an internal mounting cavity, and a through hole communicating with the mounting cavity at the top; a combination button, an upper stationary contact assembly, and a lower stationary contact assembly are disposed within the mounting cavity; the combination button includes two sets of conductive sheet assemblies arranged vertically, each conductive sheet assembly including a semi-circular arc-shaped elastic sheet; both the upper and lower stationary contact assemblies include two sets of sickle-shaped stationary contacts, which form arc-shaped surface contact with the arc-shaped elastic sheet; the combination button has a free state and a full-stroke state along the axial direction: in the free state, the upper arc-shaped elastic sheet contacts the upper stationary contact assembly, and the two normally closed contacts are connected; in the full-stroke state, the lower arc-shaped elastic sheet contacts the lower stationary contact assembly, and the two normally open contacts are connected, while the upper arc-shaped elastic sheet separates from the upper stationary contact assembly, and the normally closed contacts are open. This application improves the stability and reliability of contact resistance.

The invention discloses a circuit breaker time difference test system. The system comprises a circuit breaker to be tested and a tester, wherein the circuit breaker is provided with a phase selection closing device; a port binding post on one side of a fracture of the circuit breaker is short-circuited and connected to an N binding post of the tester, and port binding posts A, B and C on the other side are connected to corresponding binding posts A1, B1 and C1 in a first connecting phase of the tester; in addition, a port binding post on one side of a pair of normally-open auxiliary contacts of the circuit breaker is connected with a wire connected to an N binding post of the tester, and a port binding post on the other side of the normally-open auxiliary contacts is connected to a binding post A2 of a second phase of the tester; when the tester is used for testing the characteristics of the circuit breaker, besides the action time and synchronism of three-phase contacts of the circuit breaker are measured, corresponding auxiliary contacts of the circuit breaker are connected at the same time, operation is carried out according to testing regulations, the time difference of the main contacts and the auxiliary contacts during closing and opening of the circuit breaker can be accurately measured, and a basis can be provided for setting of related fixed values such as fast switching.

The utility model discloses an armature reed assembly and a vacuum relay, and belongs to the field of vacuum relays. The armature reed assembly comprises an armature and a connecting support. The armature is provided with a mounting surface, a fixing part is arranged on the mounting surface, the connecting support is arranged on the mounting surface and comprises a support body and a connecting part, the connecting part is arranged at one end of the support body, the other end of the support body is arranged on the mounting surface, the support body is connected with the fixing part, and the fixing part supports the support body. In the embodiment of the invention, when the armature drives the bracket body to move and the bracket body drives the transmission rod to move through the connecting part, under the condition that the electromagnetic assembly applies the same force to the armature, the bracket body enables the transmission rod to be stressed more greatly, so that the normally open pressure of the normally open contact of the vacuum relay is increased.

The application relates to an anti-losing control safe driving circuit and a true safe anti-leakage protector, which is characterized in that: the safe driving circuit HAKM is used as a core device of the true safe anti-leakage protector, two trigger input ends V i1 , i2 of the core device are connected with two ends of a mutual inductor H secondary n3, a resistance R10 is connected between an e end and a driving end V DL of the secondary n3, an alternating current input end V S2 is connected with a series connection capacitor C9, a resistance R7, a fuse RD and a thermistor PTC, the series connection capacitor C9, the resistance R7, the fuse RD and the thermistor PTC are connected with a load line L2, the alternating current input end V S1 is connected with the load line N2, a relay J coil is connected between the driving end V DT and V DL , and two groups of normally open contacts of the relay J control the primary n1 and n2 of the mutual inductor H and the alternating current power supply of the load. If leakage or self failure occurs, the relay J can reliably disconnect the alternating current power supply. It can be seen that the application can prevent various fault losing controls and ensure that the power utilization is safe.

An Energy Reducing Maintenance Switch (ERMS) includes: a first switch that is normally open; a coil that is controlled by the first switch; a relay having instantaneous settings; a first normally-open contact that is controlled by the coil; a delay timer; and a second normally-open contact that is controlled by the delay timer. The coil is charged upon closing the first switch. The ERMS closes the first normally-open contact and energizes upon charging the coil. The delay timer starts to count from a first present time to a second preset time upon closing the first normally-open contact. The ERMS closes the second normally-open contact upon the delay timer starting to count. The ERMS activates the instantaneous settings of the relay, by activating an input signal to the relay, upon closing the second normally-open contact. While the delay timer counts from the first preset time to the second preset time, the second normally-open contact is closed.

To address the issue of different industrial equipment requiring different starters to adapt to various control systems and command settings, this invention discloses a flexible starter adaptable to a variety of high-power devices. This flexible starter comprises a first relay coil, a second multi-function relay coil, and a third relay coil connected in parallel. A jumper that can be selectively closed or opened is provided between the first relay coil and the second multi-function relay coil. The first relay coil controls a normally open contact of the first relay that can be shorted, the second multi-function relay coil controls a normally open contact of the second relay, and the third relay coil can selectively control a normally closed or normally open contact of the third relay.

The application discloses a three-phase open contact box, which comprises three contact box bodies and three static contacts and is integrally made by pressure injection of epoxy mixture gel, and a skirt is arranged on the outer wall of each contact box body, and the three static contacts are embedded in the corresponding contact box bodies. The three-phase open contact box comprises three-phase insulation bodies of A, B and C, and the static contact is integrated with the epoxy mixture gel. One end of the static contact is used for fixing the outgoing busbar, and the other end is matched with the breaker contact arm. The three-phase open contact box can accurately ensure the distance between the phases on the switch cabinet, so that the static contact and the breaker contact arm are not deviated or stuck when matched, thereby achieving the effect of high assembly precision and solving the discharge phenomenon caused by the misalignment or improper engagement of the contact arm.

The utility model relates to the technical field of cold shearing, in particular to a shearing protection device of a cold shearing machine, which comprises a clutch electromagnetic valve control loop and a brake electromagnetic valve control loop which are connected in parallel. And the clutch electromagnetic valve control loop and the brake electromagnetic valve control loop are respectively connected with the control unit. The utility model has the advantages that the normally open contact I of the relay KA1, the normally open contact I of the relay K2 and the coil of the relay K1 are connected in series to form a safety interlocking loop, and the design can effectively prevent the situation that the brake does not act but the clutch acts again; a normally open contact I of the relay KA2 is connected in series with a coil of the relay K2, and a normally open contact II of the relay KA1 is connected in parallel with a normally open contact of the relay KA2 I, so that the electromagnetic valve of the brake cannot be powered off when the electromagnetic valve of the clutch is powered on to work.

This application provides an anti-tipping structure for a beam pumping unit. Its irregularly shaped housing is detachably mounted on the top surface of the beam. A first mercury switch and a second mercury switch are respectively mounted on the inner wall of one side plate of the irregularly shaped housing. The angle between the first mercury switch and the first plane is 173°, and the angle between the second mercury switch and the first plane is 7°. The first plane is parallel to the plane containing the top plate of the irregularly shaped housing. One end of a cable is electrically connected to the first mercury switch and the second mercury switch, respectively. The low-voltage power supply at the output of the power converter is electrically connected to the other end of the cable and a relay. The normally open contacts of the relay, specifically the first and second control output terminals, are electrically connected to the control circuit of the pumping unit's motor for controlling the motor's operation. This device is low-cost, highly practical, and can detect whether the horizontal tilt of the pumping unit's beam exceeds the limit.

The invention discloses a switch with high safety and high availability, which comprises a plurality of independent switch components integrated together, each independent switch component is at least provided with a normally open contact and a normally closed contact, and the normally open contact and the normally closed contact are linked through a first mechanical component. The normally-open contact and the normally-closed contact control the switch action through a second mechanical part, the normally-open contact of each independent switch part is connected to an external function loop in series, and the normally-closed contact of each independent switch part is connected to an external monitoring loop in series. The switch provided by the invention has four high-safety advantages: (1) when a fault occurs, the switch is oriented to a safety design and has high availability; (2) no single-point fault exists; (3) the dangerous fault rate is lower than 1E-8 / h; and (4) the danger of multiple redundant channels can be detected, and fault safety monitoring under complex conditions can be realized.

The invention discloses a connecting device for an escalator and a control method, the connecting device comprises double physical safety links, and two completely independent and electrically isolated physical safety links, namely a link A and a link B, are laid in parallel on the whole line of the escalator; the distributed safety node comprises a safety relay unit which comprises two pairs of normally open contacts KA and KB which are forced to guide and are completely synchronous in state, and the two pairs of normally open contacts KA and KB are respectively connected in a physical safety link A and a physical safety link B in series; the physical link on-off detection circuit is used for directly detecting voltage / current of a link A and a link B and judging the on-state of the link A and the link B, and the diagnosis excitation and measurement circuit comprises a precise constant current source and a high-precision voltage sampling and demodulation circuit and can be switched to a diagnosis bus. A test signal is injected into a diagnosis loop formed by a plurality of node coils, and a response is measured, so that a tough and adaptive safety protection system is constructed, and potential network attacks and internal faults can be resisted.

The utility model relates to an anti-backflow quick-connection plug device, and belongs to the technical field of quick-connection plug devices. The female plug is in plug-in fit with the male plug; the auxiliary operating part is arranged on the female plug, a common end, a normally open contact and a normally closed contact are arranged on the auxiliary operating part, the common end is electrically conducted with the plug end of the female plug, the normally open contact is used for being connected with an emergency power supply, and the normally closed contact is used for being connected with a mains supply. According to the invention, the auxiliary operation member is arranged on the female plug, when the commercial power is interrupted, an operator switches power supply to the emergency power supply through the switch, the normally open contact is connected with the common end, the normally closed contact is disconnected with the common end, and the emergency power supply and the commercial power cannot be connected at the same time through physical isolation. The risk of reverse current generated when the emergency power supply is connected to the power grid is avoided, and power supply safety is ensured.

The utility model discloses a release device and a low-voltage electric appliance, and belongs to the technical field of low-voltage electric appliances. The release device comprises a connecting rod mechanism which is connected with the release device; the shifting rod mechanism is located on one side of the connecting rod mechanism and connected with the connecting rod mechanism. The normally open contact structure is located on one side of the driving lever mechanism and can abut against the driving lever mechanism. The normally-closed contact structure is located on the side, away from the normally-open contact structure, of the shifting rod mechanism and can abut against the shifting rod mechanism. The release device is provided with an independent normally-open contact structure and an independent normally-closed contact structure, the handle is pushed to drive the shift lever mechanism to move, and shift sheets of the normally-open contact structure and the normally-closed contact structure are pushed to move, so that opening and closing of the normally-open contact structure and the normally-closed contact structure are controlled at the same time; therefore, two independent auxiliary loops can be controlled at the same time, the problem that in the prior art, only one auxiliary loop can be controlled by one release device is solved, and the control efficiency and the safety of the circuit can be effectively improved.

The utility model provides a circuit unit, comprising a single-pole double-throw relay comprising a common terminal, a normally closed contact and a normally open contact; the switch resistor series branch comprises a first switch unit and a resistor unit which are connected in series, the first end of the switch resistor series branch is connected with the normally-closed contact, the second end of the switch resistor series branch is connected with the normally-open contact, the common end of the single-pole double-throw relay is used for being connected with a power supply circuit, and the common end of the single-pole double-throw relay is used for being connected with the normally-open contact. The second end of the switch resistor series branch is used for being connected with a power conversion circuit, and the output end of the power conversion circuit comprises a bus capacitor.

The embodiment of the invention provides a control circuit, a detection circuit, an adhesion detection method and a circuit topological structure of a relay. The detection circuit comprises a sixth resistor, two ends of which are respectively coupled with a third node and a second reference ground; two ends of the seventh resistor are respectively coupled with a fourth power supply end and a fourth node, and the fourth node is used for being coupled with the normally closed contact; the detection module is configured to enable a fifth node to be conducted with a third reference ground under the control of a first control signal of a fourth node under the condition that the common contact is coupled with the normally open contact, and an output end outputs a first detection signal; and the controller is further configured to enable the fifth node to be disconnected from the third reference ground under the control of a second control signal of the fourth node under the condition that the common contact is coupled with the normally closed contact, the output end outputs a second detection signal, and the second detection signal is different from the first detection signal. Through the detection circuit, whether the relay is adhered or not can be detected.