476results about "Protective switch terminals/connections" patented technology

The invention provides a miniature breaker with a novel current detection assembly. The miniature breaker with a novel current detection assembly includes a breaker main body and a novel current detection assembly, wherein the novel current detection assembly includes a Hall magnetic field sensor, a current detection wire, and a Hall magnetic field sensor detection circuit board; a detection Hallmagnetic field sensor in the Hall magnetic field sensor without a magnetic core is used to detect a magnetic field which is generated from the current detection wire, and an environment Hall magneticfield sensor in the Hall magnetic field sensor is used to detect a background magnetic field in the environment; and the difference values detected by the detection Hall magnetic field sensor and theenvironment Hall magnetic field sensor are processed to obtain the magnitude of the current, so as to eliminate the interference of the background magnetic field and enable the detected current to bemore accurate. Therefore, the breaker with the novel current detection assembly can accurately perform opening and closing.

The invention discloses a magnetic rotation arc extinguishing circuit breaker contact structure, and belongs to the technical field of high-voltage electric connectors. Comprising an arc extinguishing device, a connecting device and a circuit breaker contact, the arc extinguishing device can be connected with the circuit breaker contact through the connecting device, the arc extinguishing device is integrally of a cylindrical structure, a longitudinal magnetic field is generated when current flows through the arc extinguishing device, and when an arc passes through the middle area of the arc extinguishing device, the arc is effectively stretched and rapidly extinguished under the action of the magnetic field. The connecting device comprises a centering piece and a fixing assembly, the centering piece can fix the arc extinguishing device on the axis of the centering piece, and the fixing assembly can fix the arc extinguishing device. Through the arc extinguishing assembly, a longitudinal magnetic field is formed when current passes through the arc extinguishing assembly, and the arc rotates and stretches along a spiral path under the action of magnetic field force, so that the arc extinguishing efficiency of the circuit breaker is remarkably improved, and the problem that the magnetic field direction is inconsistent with the arc flowing direction in the prior art is solved.

The invention relates to the field of circuit breakers, and particularly discloses a grounding circuit breaker, which comprises a box body structure, a fixing piece and a clamping piece, the use of the box body structure not only can limit the sliding of the fixing piece, but also can tighten the clamping piece, thereby clamping the electric wire and preventing the electric wire from falling off and inclining. The fixing piece is used to replace the original mode of fixing the wire by screws, so that the operation steps are simplified, the wire is more quickly and conveniently fixed, the wire is effectively prevented from sliding left and right, and the problems of unstable wire installation, wire loosening, poor contact and the like are avoided; the use of the clamping member not only can clamp the wire, improve the stability of the fixing member for fixing the line and prevent the wire from loosening, but also can wrap the wire, so that the wire cannot move left and right, the fixing member can accurately clamp the wire, and the reliability of the fixing member is improved.

The object of the present invention relates to an electromechanical system for interrupting (1) an electric current exhibiting an overload anomaly and / or a short circuit and / or a residual current, comprising - at least one set (2) of current input connection terminals comprising at least, on the one hand, a connection terminal (2a) dedicated to the phase current and, on the other hand, a connection terminal (2b) dedicated to the neutral current, - at least one thermal relay (3) and / or an electromagnetic relay (4) and / or a differential current measuring device (5) coupled to a switch, characterized in that the interruption system (1) also comprises at least two sets (6) of current output connection terminals, each comprising at least one connection terminal (6a) dedicated to the phase current and one connection terminal (6b) dedicated to the neutral current, so that, on the one hand,Each output phase current connection terminal (6a) is connected to the input phase current connection terminal (2a) at a common node (7a), and, conversely, each output neutral current connection terminal (6b) is connected to the input neutral current connection terminal (2b) at a common node (7b).

The invention relates to an N-pole module assembly of a circuit breaker and the circuit breaker. The N-pole module assembly of the circuit breaker comprises a main body function module and a current detection module, and further comprises a first N-pole conductive plate fixedly integrated on the main body function module and a second N-pole conductive plate fixedly integrated on the current detection module, and the main body function module and the current detection module are respectively two independent modular structures. And the first N-pole current-conducting plate and the second N-pole current-conducting plate are fixedly and electrically connected to form an N-pole electric loop. According to the invention, the complicated bending and wiring process of the soft wire in the N-pole module assembly in the prior art is avoided, the assembly is convenient, and the automatic assembly can be realized. Moreover, through the special arrangement of the relative positions of the N-pole electric loop and the L-pole electric loop, the Lorentz force generated by the magnetic field generated by the current on the N-pole electric loop on the electric arc in the circuit breaker unit can assist the electric arc to be further pushed and lengthened, and the effect of enhancing the magnetic quenching function can be achieved.

Electrical protection device, distribution assembly, and associated electrical switchgear. This electrical protection device (300), configured to electrically connect an electrical load (M) to an electrical power source (S), includes incoming terminals (302), outgoing terminals (304), and switching means (310) actuated by a bistable actuator (324). A microcontroller (320) is provided to generate a fault signal (S320), which triggers the actuator, and an output signal (S321), which is different from the fault signal. The protection device includes a supervisory circuit (500), which is interposed between the microcontroller (320) and the actuator (324) and which includes an oscillator (510) configured to generate a periodic signal (S510).The monitoring circuit is configured to generate a trigger signal (S324) when, alternatively, the output signal (S321) of the microcontroller (320) is absent, or the periodic signal (S510) of the oscillator (510) is absent, or when a fault signal (S320) is emitted. See Figure 6 for abbreviations.

The invention provides a circuit breaker execution module and an assembly process thereof. The circuit breaker execution module comprises a first side cover, a second side cover, a tripping execution mechanism, a test device and an electronic component board, the first side cover is provided with a first mounting position close to the first side in the thickness direction and a second mounting position close to the second side in the thickness direction; the tripping execution mechanism and / or the test device are / is assembled on the first mounting position, and the tripping execution mechanism is provided with a first pin group extending towards the second side direction; the test device is provided with a second pin group extending towards the direction of the second side; the electronic component board is assembled on the second mounting position; the first pin group and / or the second pin group are / is connected with the electronic component board; the problems that wire electric connection operation is tedious, unreliable and incapable of achieving automation are solved.

The utility model relates to the technical field of electric connectors, in particular to a quick connector which comprises a connector body, the connector body comprises a connecting end used for being connected with a circuit breaker and a plugging end used for being connected with a wiring copper bar on a bus adapter, the connecting end and the plugging end are integrally formed in a bending mode, and the connecting end is connected with the wiring copper bar. The plugging end comprises a first clamping piece and a second clamping piece, the first clamping piece and the second clamping piece are symmetrically arranged on the two sides of the connecting end, the first clamping piece and the second clamping piece are provided with a first clamping groove and a second clamping groove respectively, and the first clamping groove and the second clamping groove are used for simultaneous plugging of wiring copper bars. According to the utility model, the connection structure of the wiring copper column is optimized through the connector which can be rapidly plugged, the connector is a detachable independent connector, the connection direction can be changed through bending, the connector is connected with the wiring copper bar in a plugging manner, and the connection steps are simple.

The utility model discloses a residual current operated circuit breaker, which relates to the technical field of circuit breakers and comprises a shell and a contact box assembled in the shell, a wire outlet end static contact and a wire inlet end static contact are respectively assembled on two sides of the contact box, the wire outlet end static contact comprises a connecting part, an extending part and a mounting part, and the connecting part is connected with the extending part. Wherein the mounting part is integrally of a U-shaped structure, a cavity matched with the U-shaped mounting part is formed in the contact box, the extension part is located between the connecting part and the mounting part, the extension part, the connecting part and the mounting part are integrally formed through extrusion, the extension part is additionally arranged to connect the connecting part and the mounting part, and the extension part, the connecting part and the mounting part are integrally formed through extrusion, so that the length of the wire outlet end static contact is effectively increased; and large current can pass through.

The invention discloses a safe power distribution device and system, and the device comprises a power distribution cabinet, the side wall of the inner cavity of the power distribution cabinet is provided with a pedestal, the side wall of the pedestal is provided with a plurality of circuit breaker assemblies, each circuit breaker assembly comprises a circuit breaker body, the side wall of each circuit breaker body is provided with an operation handle, and the bottom of the inner cavity of the power distribution cabinet is provided with a zero line bar assembly. According to the safe power distribution device and the safe power distribution system, the plug seat is inserted into the connector circuit breaker for overall plugging, so that the replacement is safer and faster, and the maintenance is more convenient; through the design of combining a plurality of pins with the connector assembly, synchronous, rapid and one-time establishment and separation of all electrical connections can be realized, the risk of electric shock caused by frequent operation can be avoided, secondly, the connection male seat and the connection female seat are spliced to splice the bus bar to realize on-demand expansion of the power distribution capacity and the number of loops, wire arrangement inspection is facilitated, and the working efficiency is improved. The zero line bare wire head is pressed through resilience force of the conductive reed, so that wiring is more convenient and stable.

The invention belongs to the technical field of circuit breaker performance testing, and particularly relates to a performance testing device for a circuit breaker and a frame circuit breaker, the performance testing device comprises a detection station, a conveying mechanism is arranged in the detection station, the frame circuit breaker is placed at the top of the conveying mechanism, and a centering mechanism is arranged at the top of the conveying mechanism. According to the invention, a fixed detection station is formed on the front side of the conveying mechanism through the detection table, and the conveying mechanism is matched with the transfer mechanism, so that the frame circuit breaker can move from the conveying mechanism to the fixed detection station for detection, and the frame circuit breaker in detection does not block other frame circuit breakers conveyed on the conveying mechanism; the conveying mechanism is ensured to have the conveying capacity all the time, the testing efficiency can be further improved, the conveying mechanism is matched with the transferring mechanism, the detected frame circuit breaker can be transferred to the conveying mechanism so that the detected frame circuit breaker can be conveyed to the next station, and the testing efficiency can be improved again.

The application provides a circuit breaker, comprising a shell, an incoming terminal, a solid-state circuit module, a circuit board, an operating mechanism, a release and a load terminal; the incoming terminal comprises a first input terminal and a second input terminal, the solid-state circuit module comprises an L-pole conductive part and an N-pole conductive part, the operating mechanism comprises a moving contact and a stationary contact, and the load terminal comprises a first output terminal and a second output terminal; wherein the L-pole conductive part is provided with a first extension part connected with the first input terminal and a second extension part connected with the moving contact, the N-pole conductive part is provided with a third extension part connected with the second input terminal and a fourth extension part connected with the second output terminal, and the stationary contact is provided with a conductive row connected with the first output terminal; since each module is connected by a single part, the influence of adjacent modules does not have to be considered when designing each module, and the difficulty is lower; each module can be machined and assembled respectively, and then assembled as a whole in the shell, so that the machining time is shortened.

The utility model relates to the field of circuit breakers, and discloses a mistaken touch prevention type electrical circuit breaker, which comprises a touch prevention mechanism arranged between two leads on a circuit breaker body and used for isolating the two leads; the anti-touch mechanism comprises a mounting seat arranged on the circuit breaker body; the isolation plate is arranged in the mounting seat in a lifting manner; the fixing pieces are arranged on the two sides of the isolation plate and used for fixing the isolation plate and the circuit breaker body, the circuit breaker body is provided with an installation groove for the isolation plate to move, and the installation base comprises an installation ring arranged in the installation groove and an elastic piece arranged in the installation ring. According to the utility model, the two lead wires can be isolated, and the situation that sundries fall between the two lead wires to cause short circuit of the circuit breaker body is avoided.

The circuit breaker comprises a circuit breaker body. The circuit breaker body is provided with a first sliding groove, a threaded hole and a terminal hole, wherein the first sliding groove and the threaded hole extend in the first direction, and the terminal hole extends in the second direction. The clamping and fixing component comprises a sliding pressing plate, a first transmission device and a pushing assembly, the sliding pressing plate is arranged in the first sliding groove in a sliding mode in the first direction, the sliding pressing plate is arranged on a screw rod of the screw in a sleeving mode, the pushing assembly comprises a first fixing ring and a plurality of clamping rods, and the first fixing ring is connected with the second side face; the first fixing ring is annularly arranged on the outer side of the terminal hole, the axial direction of the first fixing ring is a second direction, the multiple clamping rods are movably arranged on the first fixing ring, a clamping block is arranged at the end, close to the terminal hole, of each clamping rod, and the sliding pressing plate is connected with the end, away from the terminal hole, of each clamping rod through a first transmission device. Therefore, the circuit breaker according to the present invention can conveniently fix the wire and prevent the wire from loosening.

The invention relates to a relay (2) for mounting on a DIN rail (4), the relay comprising a base assembly (6) configured to be attached to the DIN rail, and a relay assembly (8) fixedly attached to the base assembly (6). The base assembly (6) comprises an engagement mechanism (10) for mounting the relay on the DIN rail (4), the engagement mechanism comprising a first engagement element (11) for engaging a first section (41) of the DIN rail (4) and a second engagement element (12) for engaging a second section (42) of the DIN rail (4). The first engagement element (11) is movably supported between an extended position and a retracted position, wherein the first engagement element (11) is biased to the extended position.

The application relates to the technical field of circuit breakers, and particularly discloses a plastic-clad circuit breaker protective cover which comprises a front protective plate, an upper protective plate and two side protective plates, the front protective plate, the upper protective plate and the side protective plates are vertically distributed in pairs, the side protective plates are arranged in an inverted L shape, positioning pin columns are arranged on the sides of the horizontal sections of the two side protective plates which are opposite to each other, the positioning pin columns are in sliding connection with the circuit breaker, a limiting pin column is arranged on the outer wall of the horizontal section of one of the side protective plates, a limiting groove is arranged on the outer wall of the horizontal section of the side protective plate which is away from the limiting pin column, and the limiting pin column is matched with the limiting groove. The butt joint of the plurality of protective cover bodies separates a plurality of wire-coupling cavities of the circuit breaker, the opening of the circuit breaker protective cover of the already-powered equipment in the electric cabinet is avoided, the efficiency of leading the wires of the copper nose or the copper-pipe cold-shrink tube insulating material is improved, the installation of the to-be-powered equipment is facilitated, and the safety is improved.

The embodiment of the utility model provides an interelectrode parallel assembly and a circuit breaker. The interelectrode parallel connection assembly comprises a first wiring terminal; the plurality of static contacts are respectively connected to the first wiring terminals; the plurality of moving contacts are suitable for being connected and disconnected with the corresponding static contacts; the bus piece comprises a bus part, a second wiring terminal and a plurality of connecting parts, one end of each connecting part in the plurality of connecting parts is connected to the bus part, the other end of each connecting part in the plurality of connecting parts is connected to the second wiring terminal, and the bus part is connected to the plurality of moving contacts; wherein the first wiring terminal is suitable for being connected to one of an external load and an external power supply, and the second wiring terminal is suitable for being connected to the other of the external load and the external power supply.

This utility model discloses a circuit breaker, belonging to the field of low-voltage electrical technology. The circuit breaker includes a contact structure and a leakage current test circuit. The contact structure includes a first moving contact and a conductive rod electrically connected to the first moving contact. The leakage current test circuit includes a test resistor and a spring contact. The test resistor has a first lead, and the first lead and the end of the conductive rod facing the spring contact are both abutted against and electrically connected to the first surface of the spring contact. The circuit breaker provided by this utility model adopts a lap-connection power extraction method to electrically connect the test resistor and the first moving contact, so as to realize the leakage current test circuit extracting power from the first end of the test resistor, effectively reducing the use of wires, that is, reducing the number of wire connection points and soldering points, reducing the risk of short circuit and leakage current test circuit failure, facilitating assembly, and effectively reducing manufacturing costs.

The utility model relates to a zero flying arc arc extinguishing chamber structure of circuit breaker, a zero flying arc arc extinguishing chamber structure of circuit breaker, including the casing formed by the upper cover, middle cover and base screw connection, install arc extinguishing chamber in the base, the upper and lower both ends of middle cover are equipped with corresponding several wiring terminals, the arc extinguishing chamber includes contact head support, the arc extinguishing grid piece of several connected in the both sides of contact head support and the peripheral baffle connected in the end of arc extinguishing grid piece, the peripheral baffle is equipped with the air outlet matched with the position of arc extinguishing grid piece, the base still is equipped with the baffle groove and the arc baffle of interference connection in baffle groove, the position of arc baffle corresponds with air outlet, is equipped with several through -holes on this arc baffle, the through -hole array forms the net -like structure, has realized arc baffle alignment air outlet, the arc baffle on the physical isolation blocks arc extinguishing chamber and does not completely extinguish the arc, the through -hole on arc baffle further separates arc, accelerates the remaining arc to extinguish, avoids the short circuit of circuit breaker because of the arc that sprays.

This protection device (300) comprises at least two conduction paths (303) and cut-off means (310) arranged on each of the conduction paths. The device comprises a microcontroller (320), which is configured to measure a differential current in the conduction paths with detection means (312), to evaluate a differential fault and to send a trip signal to the cut-off means when a differential fault of the first type is detected. The protection device (300) also includes a test loop (360), which is different from the detection means. The microcontroller (320) is configured to inject, into the conduction paths by means of the test loop, a first test signal representative of the electrical fault of the first type and, together with detection means, to measure the first test signal thus injected into the conduction paths.

This utility model relates to the field of positioning device technology and provides a circuit breaker installation and positioning device, including: a base, a support tray, a mounting plate, a contact plate, and a positioning mechanism. In this solution, by setting up a positioning mechanism, the rotation of the support tray allows the synchronous rod to slide within the limiting groove. The limiting groove, through its limiting effect, drives the docking groove to move up and down. The docking groove then drives the lever to move axially, thereby driving the active rod to slide axially. Simultaneously, the first and second linkage rods drive the linkage slider and the driven slider to slide synchronously. The symmetrically arranged driven slider and the centrally located active slider then position the circuit breaker in three directions and lock it against the contact plate, achieving rapid installation and positioning of the circuit breaker. Furthermore, the synchronous rod and limiting groove allow multiple positioning mechanisms to move synchronously during rotation, ensuring circuit breaker positioning accuracy while significantly improving production cycle time.

The invention relates to an overload protection device (1) for protecting electrical components (2), comprising at least two electrical components (2), comprising a carrier (3), which has a plurality of connecting elements (31) for connecting the electrical components (2), and comprising at least one actuator (4), at least one separating element (6) is displaceably arranged on the carrier (3), which separating element (6) is applied by the actuator (4) with a force (F) such that the separating element (6) can be moved by the actuator (4) from a first position into a second position, and the separating element (6) interacts with the two electrical elements (2) in such a way that the separating element (6) can be moved by the actuator (4) from the first position to the second position. In the event of a thermal overload, the two electrical components (2) can be transferred by the separating element (6) to the second position thereof.

Protective device, protective assembly, electrical panel, and associated test method. This protective device (300) includes at least two conduction paths (303) and switching means (310) arranged on each of the conduction paths. The device includes a microcontroller (320), which is configured to measure a differential current in the conduction paths with detection means (312), to evaluate a differential fault, and to send a trip signal to the switching means upon detection of a first-type differential fault. The protective device (300) also includes a test loop (360), which is separate from the detection means.The microcontroller (320) is configured to inject, via the test loop, a first test signal representative of a first type electrical fault into the conduction paths and, simultaneously, to measure, using detection means, the first test signal thus injected into the conduction paths. See Figure 5 for abbreviations.

The utility model relates to the technical field of circuit breakers, in particular to a monitoring type immersion electric shock prevention circuit breaker, which comprises a circuit breaker, a sealing element and a sealing ring, and is characterized in that the circuit breaker comprises a mounting seat, the outer wall of the mounting seat is provided with a wiring hole, the two sides of the inner wall of the wiring hole are both provided with limiting holes, and the sealing element is mounted in the mounting seat, the sealing piece comprises an insulating plate, and the circumferential wall of the insulating plate protrudes outwards to form two extending parts. According to the device disclosed by the utility model, the fastening bolt is rotated to spirally move into the second threaded hole, at the moment, the fastening bolt extrudes the insulating plate inwards, the sealing ring on one side, close to the wiring terminal, of the insulating plate extrudes the connecting sheet, the sealing ring is pressed in the first pressing groove, and the second pressing groove in the fastening bolt extrudes the sealing ring on the other side of the insulating plate; therefore, the connection part of the connection sheet and the wiring terminal can be sealed, and the oxidation phenomenon of the wiring terminal and the wire wiring end can be avoided.

The utility model relates to the technical field of circuit breakers, and discloses a circuit breaker convenient to install in a narrow space, which comprises a circuit breaker body and wire slots arranged at the upper end and the lower end of the circuit breaker body, the circuit breaker is firstly installed on a sliding rail, a connecting block is pulled out from an installation slot, a wire is inserted into the wire slots, and the circuit breaker is installed on the sliding rail. At the moment, a connecting block can be pushed into a wire inserting groove, a sliding block in the connecting block in an initial state is stored in a sliding groove, when the connecting block is pushed back into a mounting groove, a first spring can automatically push the sliding block outwards to slide into the wire inserting groove, and an inserted wire is automatically fixed and limited; according to the convenient-to-install circuit breaker suitable for the narrow space, multiple limiting can be carried out when the connecting block is pushed in through the arrangement of the multiple sliding blocks, the fixing effect is enhanced, when the convenient-to-install circuit breaker suitable for the narrow space is used, wires can be fixed by moving the connecting block, the convenient-to-install circuit breaker suitable for the narrow space is suitable for installation of wires of different thicknesses, and no auxiliary fixing tool needs to be used.

The application relates to the low-voltage electrical field and particularly relates to a circuit breaker, a first contact system of which comprises a first moving contact mechanism, a first static contact and a second static contact arranged on the two sides of the first moving contact mechanism respectively, a first arc extinguishing system comprising a first arc extinguishing chamber and a second arc extinguishing chamber, a button mechanism, an operating mechanism and the first moving contact mechanism being sequentially and drivingly connected; the button mechanism, the operating mechanism and a first incoming line end are sequentially arranged along the length direction of the circuit breaker and are all located on one side in the width direction of the circuit breaker; the first outgoing line end, the second arc extinguishing chamber, the first moving contact mechanism and the first arc extinguishing chamber are sequentially arranged along the length direction of the circuit breaker and are located on the other side in the width direction of the circuit breaker, the first outgoing line end and the button mechanism are located on one end in the length direction of the circuit breaker, and the first arc extinguishing chamber and the first incoming line end are located on the other end in the length direction of the circuit breaker; the circuit breaker is reasonable in layout and compact in structure.

The invention discloses a circuit breaker assembling platform which is used for assisting installation of a circuit breaker and comprises a bottom plate assembly, an end limiting assembly, a rotation limiting assembly, a support fixing assembly, a wire clamping assembly and a guide placement assembly, the end limiting assembly is provided with an adjusting hole, and the rotation limiting assembly comprises a rotation limiting main body and a rotating shaft assembly. The rotation limiting body is rotationally installed on the bottom plate assembly through the rotating shaft assembly, and a limiting protrusion is arranged at the front end of the rotation limiting body. The circuit breaker is placed in the clamping gap, the circuit breaker is fixed between the end limiting assembly and the rotation limiting assembly by rotating the rotation limiting main body, the support for auxiliary installation is fixed to the support fixing assembly, and the copper wire for auxiliary installation is arranged on the wire clamping assembly and the guide placement assembly. By the adoption of the device, the effect of positioning installation can be achieved, the copper bars, the supports and the wires can be installed in an auxiliary mode, installation is convenient, and the problems that installation efficiency is low and installation is inconvenient are solved.

This electrical protection device (300), configured to electrically connect an electrical load (M) to an electrical power source(S), comprises incoming terminals (302), outgoing terminals (304), and cut-off means (310) actuated by a bistable actuator (324). A microcontroller (320) is provided to generate a fault signal (S320), which triggers the actuator, and an output signal (S321), which is different from the fault signal. The protection device comprises a supervision circuit (500), which is interposed between the microcontroller (320) and the actuator (324) and includes an oscillator (510) configured to generate a periodic signal (S510). The supervision circuit is configured to generate a trigger signal (S324) when, alternatively, the output signal (S321) of the microcontroller (320) is absent, or the periodic signal (S510) of the oscillator (510) is absent, or when a fault signal (S320) is emitted.

The invention relates to a modularized intelligent circuit breaker, which relates to the technical field of intelligent power grids and comprises a base, an operation assembly arranged on the base and a front cover fixedly arranged on the front side of the base and used for protecting the operation assembly. A protection assembly is arranged on the base, an installation cavity is formed in the base, the protection assembly comprises a lower shell arranged in the installation cavity and a top cover fixedly arranged on the front side of the lower shell, and an overload protection mutual inductor, a zero sequence mutual inductor and a metering mutual inductor are installed in the lower shell; a plurality of conducting strips penetrating through the overload protection mutual inductor, the zero sequence mutual inductor and the metering mutual inductor are installed on the lower shell, the two ends of each conducting strip are fixedly provided with a plug-in piece and a lug plate, and the side face, away from the protection assembly, of the installation cavity is provided with a receding notch; according to the utility model, the overload protection mutual inductor, the zero sequence mutual inductor and the metering mutual inductor are integrated and preassembled in the protection assembly formed by the lower shell and the top cover, and the conducting strip penetrating through the three mutual inductors and the plug-in piece and the lug plate at the two ends are matched, so that the modular design of the protection assembly is realized.