Trip Device of Manual Motor Starter

Abstract

The present invention relates to a circuit breaker for motor protection, and more specifically, to a trip device for a circuit breaker for motor protection. According to the trip device of a circuit breaker for motor protection according to one embodiment of the present invention, unlike the method in which a shift lever acts on a latch holder of an opening / closing mechanism through a conventional compensation bimetal, the shift lever acts directly on the latch holder without passing through a compensation bimetal, thereby reducing operating errors and improving stability.

Description

Technology Field

[0001] The present invention relates to a circuit breaker for motor protection, and more specifically, to a trip device for a circuit breaker for motor protection. Background Technology

[0002] Generally, a manual motor starter (MMS) is a device used in circuits with an AC insulation voltage of 690V (frequency 50Hz or 60Hz) or less, installed at the front end of a motor, and is a device that protects the system and load equipment by operating to interrupt the system when a fault current occurs due to overcurrent, phase loss, phase reverse, short circuit, ground fault, etc.

[0003] FIG. 1 shows an external perspective view of a circuit breaker for motor protection according to the prior art, and FIG. 2 shows an internal perspective view of a circuit breaker for motor protection according to the prior art.

[0004] The above-described motor protection circuit breaker is equipped with a detecting unit (tripping unit) (30) that detects fault currents such as overcurrent, phase loss, reverse phase, short circuit current, and ground fault when they occur inside the enclosure (2), an operating mechanism (20) that trips the circuit breaker according to the detection signal of the detecting unit, a contact unit (10) that opens and closes the line in conjunction with the operation of the operating mechanism, and an arc extinguishing unit (40) that extinguishes the arc generated when the contacts of the contact unit are separated during interruption and discharges it to the outside. Additionally, an auxiliary contact unit that sends a control signal to an auxiliary device according to the operation of the operating mechanism may also be provided.

[0005] In the above-described motor protection circuit breaker, when normal current is supplied, the moving contact (12) and the fixed contact (11) of the contact part (10) are connected to allow the current flowing into the power side terminal (3) to flow to the load side terminal (4). However, when a fault current occurs, the detection part (30) detects this and drives the switching mechanism part (20), and by the operation of the switching mechanism part (20), the moving contact (12a) of the moving contact (12) is separated from the fixed contact (11a) of the fixed contact (11), thereby blocking the current from flowing to the load side.

[0006] The detection unit (trip unit) (30) of a circuit breaker for motor protection according to the prior art has the following configuration.

[0007] The detection unit (30) has a trip unit body (31) forming the base of the detection unit (30), a fixed contactor (11) coupled to the lower part of the trip unit body (31), a heater assembly (bimetal (39), a heater (38), and a bimetal supporter (40)) coupled to the upper part of the trip unit body (31) and detecting heat, an instantaneous coil (35) coupled to the upper part of the bimetal supporter (40), a core unit (fixed core (32), a movable core (33), and a core spring (34)) inserted into the instantaneous coil (35), a terminal rod (41) coupled to the fixed core (32) and the trip unit body (31), and an instantaneous trip lever (36) rotatably coupled to the trip unit body (31).

[0008] At this time, the instantaneous operation of the detection unit (30) is as follows.

[0009] When an instantaneous current is applied to the circuit, current flows through the terminal load (41) to the instantaneous coil (35), and the fixed core (32) is magnetized by the magnetomotive force.

[0010] As the fixed core (32) becomes magnetized, the movable core (33) is attracted to the fixed core (32) and moves upward. As the movable core (33) moves upward, it pushes one end of the instantaneous trip lever (36) to rotate the instantaneous trip lever (36). The other end of the instantaneous trip lever (36) moves downward and presses the trip plate (25) downward. The trip plate (25) presses the latch holder (23) of the opening / closing mechanism (20) to operate the opening / closing mechanism (20) and presses the crossbar (29) to separate the movable contact (12a) and the fixed contact (11a).

[0011] Here, instantaneous operation refers to a function that rapidly cuts off power when a massive instantaneous current flows due to a short circuit in the load or lightning strike, and the instantaneous setting current is set from 2 times to as much as 20 times the rated current. When an abnormal current exceeding the instantaneous setting current is detected by the detector, the cutoff operation is performed in a very short time.

[0012] The instantaneous current setting value of conventional motor protection circuit breakers is fixed. For example, the instantaneous current value is designed to operate at 13 times the rated current.

[0013] Meanwhile, the delayed trip operation of the motor protection circuit breaker is as follows.

[0014] When the bimetal (39) of the tripping unit (30) bends due to the heat generated when an overcurrent flows through the circuit, the shift lever (45) advances. The shift lever (45) contacts the compensation bimetal (46) to move the compensation bimetal (46), and the compensation bimetal (46) rotates the latch holder (23) of the opening / closing mechanism unit (20) counterclockwise. Accordingly, the restraint on the latch (24) is released. When the restraint by the latch holder (23) is released, the latch (24) rotates by the restoring force of the main spring (not shown). Subsequently, the components of the opening / closing mechanism unit (20) move sequentially in conjunction and press the crossbar (29), causing the movable contact (12) to be separated from the fixed contact (11) and the circuit to be cut off.

[0015] FIG. 3 shows a perspective view of a motor protection circuit breaker according to the prior art with the upper portion removed. FIG. 4A and FIG. 4B show perspective views of a shift lever.

[0016] The shift lever (45) is used for testing the product in addition to the delayed trip function. That is, when a user pushes the shift lever (45) in the direction of the compensation bimetal (46) using a tool, the latch holder (23) is released and the trip operation is performed.

[0017] Here, the shift lever (45) of the motor protection circuit breaker is composed of two lever plates (45b) arranged in parallel and a lever (45a) connected to the two lever plates (45b). Here, the two lever plates (45b) and the lever (45a) are joined to each other by a snap-fit ​​connection or a pin connection, etc. FIG. 4B shows that a snap-fit ​​hole (45b1) is formed in the two lever plates (45b), and a snap-fit ​​projection (45a1) is formed in the lever (45a).

[0018] Meanwhile, each of the two lever plates (45b) has an elongated hole (45c) formed therein and is inserted into the guide projection (2a) of the outer casing (2).

[0019] And, on one side of the shift lever (45), a contact portion (45d) that contacts the compensation bimetal (46) is formed protruding.

[0020] When the user inserts the tool into the insertion hole (5) of the outer casing (2) and moves the shift lever (45) in the forward direction, the contact part (45d) moves the compensation bimetal (46) forward, and the compensation bimetal (46) moves the latch holder (23), thereby performing a forced trip operation.

[0021] Meanwhile, the dial assembly (47) is provided to regulate the rated current of the compensation bimetal (46).

[0022] As described above, many parts are required to perform the trip test operation of the circuit breaker. A shift lever (46) consisting of two lever plates (45b) and a lever (45a) is provided to perform the forced trip operation, and a compensation bimetal (46) and a dial assembly (47) are involved to operate the latch holder (23). This is not an essential element for the forced trip operation. The problem to be solved

[0023] The present invention has been devised to solve the aforementioned problems, and its purpose is to improve operational stability by providing a trip device that directly contacts the opening and closing mechanism without passing through a compensation bimetal during a forced trip operation.

[0024] Another objective is to provide a trip device for a motor protection circuit breaker that improves operational stability by reducing the number of parts required to perform a forced trip operation, and achieves material cost reduction and increased productivity. means of solving the problem

[0025] A trip device for a circuit breaker for motor protection according to one embodiment of the present invention comprises: a latch holder that restrains a latch of an opening / closing mechanism; and a shift lever that is movably installed on a frame and moves in a forward / backward direction to allow or release the restraint of the latch holder.

[0026] An upper-facing upper-facing partition protrusion is formed on the upper-facing partition of the above frame, and

[0027] A guide projection for guiding the shift lever is formed on the protruding part of the upper partition wall.

[0028] In addition, the shift lever includes a first plate and a second plate arranged side by side.

[0029] In addition, the first plate and the second plate have a plurality of elongated holes formed along the length direction into which the guide projection is inserted.

[0030] In addition, among the above-mentioned slots, the first slot positioned at the front is formed to be longer than the second slot positioned at the rear.

[0031] In addition, the front portions of the first plate and the second plate are provided with a protrusion that protrudes upward.

[0032] In addition, an insertion portion is formed in the above-mentioned protrusion, into which the bimetal of the detection unit is inserted.

[0033] In addition, the first plate is formed with a front portion that is thicker than the rear portion.

[0034] In addition, it includes a connecting part that connects the first plate and the second plate.

[0035] In addition, an insertion groove is formed in the above-mentioned connecting portion into which the upper portion of the bimetal is inserted.

[0036] And, the above protrusion is provided with a pressure portion that protrudes in the direction of the latch holder. Effects of the invention

[0037] According to the trip device of a circuit breaker for motor protection according to one embodiment of the present invention, unlike the method in which a shift lever acts on a latch holder of an opening / closing mechanism through a conventional compensation bimetal, the shift lever acts directly on the latch holder without passing through a compensation bimetal, thereby reducing operating errors and improving stability.

[0038] In addition, the shift lever consists of a single component, which improves consistency and enhances productivity during operation.

[0039] In addition, production costs are reduced as the compensation bimetal and dial assembly are omitted. Brief explanation of the drawing

[0040] FIG. 1 is an external perspective view of a circuit breaker for motor protection according to the prior art. FIGS. 2 and FIGS. 3 are internal perspective views of a circuit breaker for motor protection according to the prior art. FIG. 2 shows the front portion cut off, and FIG. 3 shows the top portion removed. FIGS. 4A and FIGS. 4B are perspective views of a trip shift lever applied to a circuit breaker for motor protection according to the prior art. FIG. 5 is an external perspective view of a circuit breaker for motor protection according to one embodiment of the present invention. FIG. 6 is an internal perspective view of a circuit breaker for motor protection according to one embodiment of the present invention. It shows the On state. FIG. 7 is a cross-sectional view of a circuit breaker for motor protection according to one embodiment of the present invention. It shows the Off state. FIG. 8 is an internal perspective view of a circuit breaker for motor protection according to one embodiment of the present invention. It shows a state in which the upper frame has been removed. FIGS. 9A and FIGS. 9B are perspective views of a shift lever applied to a circuit breaker for motor protection according to one embodiment of the present invention. FIGS. 10 to 13 are operational diagrams of a switching mechanism in a circuit breaker for motor protection according to an embodiment of the present invention. FIG. 10 shows an Off state, FIG. 11 shows an On state, and FIGS. 12 and 13 show a Trip state. FIG. 12 shows an Instant Trip state, and FIG. 13 shows a Delayed Trip or Forced Trip state. Specific details for implementing the invention

[0041] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, this description is intended to be detailed enough for a person skilled in the art to easily practice the invention, and it does not imply that the technical scope and concept of the present invention are limited by these drawings.

[0042] The terms "part" or "part" used to refer to components in this invention are not used for any limiting purpose and may be omitted.

[0043] FIG. 5 is an external perspective view of a circuit breaker for motor protection according to an embodiment of the present invention. FIG. 6 is an internal perspective view of a circuit breaker for motor protection according to an embodiment of the present invention. It shows the On state. FIG. 7 is a longitudinal cross-sectional view of a circuit breaker for motor protection according to an embodiment of the present invention. It shows the Off state. FIG. 8 is an internal perspective view of a circuit breaker for motor protection according to an embodiment of the present invention. It shows the state in which the upper frame is removed. With reference to the drawings, the trip device of the circuit breaker for motor protection according to each embodiment of the present invention will be described in detail.

[0044] A trip device for a motor protection circuit breaker according to one embodiment of the present invention comprises: a latch holder (147) that restrains a latch (143) of an opening / closing mechanism (140); and a shift lever (170) that is movably installed on a frame (102) and moves in a forward / backward direction to allow or release the restraint of the latch holder (147); wherein an upper-facing upper-facing partition protrusion (102a) is formed on the upper-facing partition protrusion (102a), and a guide projection (102b) that guides the shift lever (170) is formed on the upper-facing partition protrusion (102a).

[0045] A trip device for a motor protection circuit breaker according to one embodiment of the present invention includes a detecting unit (or trip unit) (150) that detects and trips when a fault current such as overcurrent, phase loss, reverse phase, short circuit current, or ground fault occurs, an operating mechanism (140) that trips the circuit breaker according to the detection signal of the trip unit (150), a contact unit (110) that opens and closes the line in conjunction with the operation of the operating mechanism (140), and an arc extinguishing unit (120) that extinguishes the arc generated when the contacts of the contact unit (110) are separated during interruption and discharges it to the outside.

[0046] The enclosure (101) of the motor protection circuit breaker installs and supports component units or components inside. The enclosure (101) may be formed of a synthetic resin.

[0047] The outer casing (101, 102, 103) is composed of an upper frame (101), a middle frame (102), and a lower frame (103).

[0048] A part of the opening and closing mechanism (140) is inserted and installed inside the upper frame (101), and a handle (141) is installed on the upper surface of the upper frame (101) to receive the user's operating force.

[0049] Inside the intermediate frame (102), an opening / closing mechanism (140) and a tripping mechanism (150) are installed. Additionally, terminal sections (105, 106) are configured at both ends along the longitudinal direction of the intermediate frame (102) and connected to a power source or a load. Meanwhile, a fixed contact (111) in the contact section (110) is fixedly installed on the lower surface of the intermediate frame (102).

[0050] In the intermediate frame (102), a phase-interval partition protrusion (102a) is formed to partition each phase. For example, in a three-phase circuit breaker composed of R phase, S phase, and T phase, two phase-interval partition protrusions (102a) are provided.

[0051] A guide projection (102b) is formed on the upper portion of the inter-partition wall protrusion (102a). The guide projection (102b) guides the linear movement of the shift lever (170). Multiple guide projections (102b) are formed on each inter-partition wall protrusion (102a) to guide the linear movement of the shift lever (170).

[0052] A contact part (110) and an arc extinguishing part (120) are installed in the lower frame (103).

[0053] Let's examine each component unit.

[0054] The contact portion (110) includes a fixed contact (111) that is fixedly installed in a part of the enclosure (101, 102, 103) and connected to a power side terminal portion (105) or a load side terminal portion (106), and a movable contact (113) that contacts or separates from the fixed contact (111) to conduct or interrupt the circuit.

[0055] A fixed contact (111) is positioned adjacent to each terminal portion (105, 106). A fixed contact (112) is provided in each fixed contact (111). The fixed contact (112) is formed from a material having excellent electrical conductivity and strong heat resistance.

[0056] A movable contact (113) is positioned at a predetermined distance from a fixed contact (111). The movable contact (113) is installed on a guide mover (115) and can move in a straight line (up and down) toward the fixed contact (111) together with the guide mover (115). The movable contact (113) is provided with a movable contact (114) formed of a material having excellent electrical conductivity and strong heat resistance.

[0057] A contact spring (117) is positioned at the bottom of the movable contactor (113) to provide elastic force to the movable contactor (113) or the guide mover (115).

[0058] An arc extinguishing section (120) is provided around the contact section (110). The arc extinguishing section (120) is provided to extinguish the arc generated at the contact section (110) when the connection is cut off.

[0059] The arc extinguishing section (120) is provided with a side plate (121) and a plurality of grids (123) coupled thereto. An arc plate (125) that guides an arc to the arc extinguishing section (120) is provided at the bottom of the contact section (110).

[0060] A detection unit or a trip unit (150) is provided to detect and trip abnormal currents, such as overcurrent or fault current, flowing in the circuit. The trip unit (150) includes a delay trip device for detecting overcurrent and an instantaneous trip device for detecting fault current (short-circuit current).

[0061] The configuration overview of the trip device is as follows.

[0062] The delay trip device is connected to the load-side terminal (106) or heater (163) and moves a bimetal (161) that bends due to heat generated when an overcurrent flows, a shift lever (170) that moves due to the bending of the bimetal (161), and a latch holder (147) of the opening / closing mechanism (140) that rotates due to the shift lever (170).

[0063] The instantaneous trip device includes an instantaneous coil (157) that generates an induced electromagnetic force when a fault current flows through the load-side terminal (106), a fixed core (152) fixedly installed inside the instantaneous coil (157), a movable core (153) that moves by the induced electromagnetic force, an instantaneous trip lever (155) that moves by receiving the force of the movable core (153), and a trip plate (156) that moves in conjunction with the instantaneous trip lever (155) and moves the latch holder (147).

[0064] Let's take a closer look at the trip section (150).

[0065] A trip body (151) is provided. Delay trip device components and instant trip device components are installed in the trip body (151).

[0066] A heater assembly (161, 162, 163) is provided. The heater assembly (161, 162, 163) includes a bimetal (161), a heater (163), and a bimetal support plate (162).

[0067] The bimetal (161) is bent by heat flowing through the terminal portion (106) or the heater (163). The bimetal (161) can be formed integrally with the bimetal support plate (162).

[0068] The heater (163) is heated by the heat flowing through the terminal (106).

[0069] The bimetal support plate (162) is connected to the trip body (151).

[0070] The heater assembly (161, 162, 163) is used as a delay trip device.

[0071] Let us examine the instantaneous trip mechanism. The instantaneous trip mechanism includes an instantaneous coil (157), a movable core (153), a fixed core (152), a core spring (154), an instantaneous trip lever (155), and a trip plate (156).

[0072] An instantaneous coil (157) is provided. The instantaneous coil (157) generates an induced electromagnetic force according to the amount of change in current occurring in the terminal portion (106). The instantaneous coil (157) is mounted on the trip portion body (151). The instantaneous coil (157) generates an induced electromotive force to cause magnetic force to be generated in the fixed core (152) and the movable core (153).

[0073] A core section (152, 153, 154) is provided. The core section includes a fixed core (152), a movable core (153), and a core spring (154). The core section is inserted and installed inside an instantaneous coil (157).

[0074] A fixed core (152) is provided. The upper part of the fixed core (152) is fitted onto the terminal rod (160) to be fixed. At this time, the fixed core (152) can be fitted onto the terminal rod (160) by a screw connection method or the like to be fixedly connected.

[0075] A movable core (153) is provided. The movable core (153) is positioned apart from the fixed core (152) and is capable of linear movement. When there is no external force, the movable core (153) is separated from the fixed core (152) by the core spring (154). When an induced electromagnetic force is generated in the instantaneous coil (157), a magnetic force is generated in the movable core (153) and the fixed core (152), causing the movable core (153) to overcome the force of the core spring (154) and be pulled toward the fixed core (152).

[0076] A lever pressing portion (153a) is formed at the lower end of the movable core (153) to actuate the instantaneous trip lever (155). The lever pressing portion (153a) may be formed in the shape of a pin protruding from the lower surface of the movable core (153). When the movable core (153) rises, the plate portion of the lever pressing portion (153a) can push up the instantaneous trip lever (155).

[0077] A core spring (154) is inserted between the fixed core (152) and the movable core (153). The core spring (154) causes the movable core (153) to be positioned away from the fixed core (152) in a normal situation where no external force is applied.

[0078] The terminal rod (160) connects the trip section (150) and the terminal section. The terminal rod (160) is connected to the load-side terminal (106). The terminal rod (160) is fixedly coupled to the trip section body (151).

[0079] The terminal rod (160) may be formed into a stepped plate shape. A fixed core (152) may be fitted onto the upper surface of the terminal rod (160). The upper surface of the terminal rod (160) is positioned above the instantaneous coil (157). The lower surface of the terminal rod (160) may form a load-side terminal portion (106).

[0080] An instantaneous trip lever (155) is provided. The instantaneous trip lever (155) has a rotating shaft portion formed thereon and is fitted into the trip portion body (151). The instantaneous trip lever (155) rotates around the rotating shaft portion.

[0081] The front end of the instantaneous trip lever (155) is inserted into the through hole of the trip plate (156). Therefore, when the instantaneous trip lever (155) rotates, it causes the trip plate (156) to operate downward.

[0082] A driven part (155a) is provided at the rear end of the instantaneous trip lever (155) and is positioned in the space formed by the lever pressing part (153a) of the movable core (153). When the movable core (153) moves upward, it pushes the driven part (155a) to rotate the instantaneous trip lever (155), and accordingly, the front end of the instantaneous trip lever (155) descends, causing the trip plate (156) to move downward.

[0083] The switching mechanism is to be described. Further reference will be made to the switching mechanism illustrated in FIGS. 10 to 12. FIGS. 10 to 12 are operational diagrams of the switching mechanism in a circuit breaker for motor protection according to an embodiment of the present invention. FIG. 10 shows the Off state, FIG. 11 shows the On state, and FIG. 12 shows the Trip state.

[0084] An opening / closing mechanism (140) is provided. The user operates the opening / closing mechanism (140) to open / close the contact part (110) and turn the circuit on or off.

[0085] The opening and closing mechanism (140) is equipped with a handle (141), a joint gear (142) that converts the movement of the handle (141) in an orthogonal axial direction, a first U-pin (149) that is sequentially connected to and interlocked with the joint gear (142), a latch (143), a second U-pin (144), and a push link (145).

[0086] The first U-pin (149) is provided between the joint gear (142) and the latch (143) and pushes or pulls the latch (143) according to the movement of the joint gear (142).

[0087] A second U-pin (144) is provided between the push link (145) and the latch (143) to mediate interaction. That is, the second U-pin (144) pushes or pulls the latch (143) according to the movement of the push link (145), or pushes or pulls the push link (145) according to the movement of the latch (143).

[0088] The latch (143) moves according to the relative movement of the first U-pin (149) and the second U-pin (144) and has an on / off locking part (143a) that contacts the latch holder (147).

[0089] The on / off locking portion (143a) is the part where the latch (143) is constrained to the latch holder (147) during on / off operation. The on / off locking portion (143a) is formed to protrude partially from the body of the latch (143). The on / off locking portion (143a) has an on / off contact surface that meets the side of the latch holder (147) at an acute angle.

[0090] The push link (145) presses the crossbar (146), and the crossbar (146) moves the guide mover (115) to open and close the contact portion (110).

[0091] The latch holder (147) restrains or releases the latch (143). In normal operation, the latch holder (147) holds the on / off locking part (143a) of the latch (143) in a restrained state, and when an overcurrent or short-circuit current occurs, it rotates to release the restraint of the on / off locking part (143a) of the latch (143) so that a trip operation occurs.

[0092] A shift lever (170) is provided for a delayed trip or a test trip. A perspective view of the shift lever (170) is shown in FIG. 9A and FIG. 9B.

[0093] The shift lever (170) is positioned on the upper surface of the upper partition protrusion (102a) of the intermediate frame (102). A plurality of guide projections (102b) are formed on each of the upper partition protrusions (102a) of the intermediate frame (102) to guide the shift lever (170) to move in a straight line.

[0094] The shift lever (170) is installed to be able to move linearly in the forward and backward direction (a direction perpendicular to the direction from the power side terminal to the load side terminal).

[0095] The shift lever (170) includes a first plate (172), a second plate (177), and a connecting part (173) connecting them.

[0096] The shift lever (170) has the first plate (172) and the second plate (177) arranged side by side.

[0097] Two elongated holes (172a, 172b) into which guide projections (102b) are inserted are formed along the longitudinal direction in the first plate (172). Here, the first elongated hole (172a) positioned at the front is formed to be longer than the second elongated hole (172b) positioned at the rear. This is to provide clearance in the first elongated hole (172a) so that movement does not become stiff.

[0098] In the first plate (172), the front portion (172c) is formed to be thicker than the rear portion. This is to support the pressure portion (175).

[0099] Two elongated holes (177a, 177b) into which guide projections (102b) are inserted are formed along the length of the second plate (177). Here, the first elongated hole (177a) positioned at the front is formed to be longer than the second elongated hole (177b) positioned at the rear. This is to provide clearance in the first elongated hole (177a) so that movement does not become stiff.

[0100] A connecting portion (173) is provided to connect the first plate (172) and the second plate (177). At this time, an insertion groove (173a) into which the upper end of the bimetal (161) is inserted may be formed in the connecting portion (173). Accordingly, when the bimetal (161) bends due to overcurrent, a delayed trip operation is performed.

[0101] An upwardly protruding portion (174) is provided at the front portions of the first plate (172) and the second plate (177).

[0102] An insertion portion (176) into which a bimetal (161) is inserted is formed in the protrusion (174). Accordingly, when the bimetal (161) bends due to overcurrent, a delayed trip operation is performed.

[0103] The user can insert a tool into the insertion hole (101a) and push the protrusion (174) forward.

[0104] A pressure portion (175) is provided on one side of the protrusion (174). The pressure portion (175) is positioned slightly below the protrusion (174). The pressure portion (175) protrudes to the extent that it touches the latch holder (147).

[0105] When the user pushes the protrusion (174) forward using a tool, the pressurizing part (175) rotates the latch holder (147), and accordingly, the tripping operation of the opening and closing mechanism is performed.

[0106] The operation of the trip device according to one embodiment of the present invention is as follows. First, the operation of the opening / closing mechanism (140) and the trip unit (150) will be examined.

[0107] First, the normal state operation without the intervention of the trip unit (150) is as follows. When the user turns the handle (141) in the Off state as shown in FIG. 10, causing the joint gear (142) to rotate clockwise, the on / off catch portion (143a) of the latch (143) is caught on the side of the latch holder (147) and is in a restrained state. Therefore, the latch (143) rotates around the on / off catch portion (143a), and the first U-pin (149) and the second U-pin (144) are pushed to the left in the drawing, causing the push link (145) to rotate counterclockwise. When the push link (145) rotates counterclockwise, the force pressing down on the crossbar (146) is removed, and the movable contactor (113) contacts the fixed contactor (111) by the elastic force of the contact spring (117), so that the circuit is energized and the handle is in the On state. That is, it switches to the state of FIG. 11. Refer to Fig. 6 for the state of the contact portion.

[0108] At this time, the latch holder (147) restrains the latch (143) to maintain the energized state. That is, the on / off locking part (143a) of the latch (143) is engaged with the latch holder (147). The opening / closing mechanism (140) maintains the state of FIG. 7 during a normal circuit energized state.

[0109] Likewise, when the user turns the handle (141) in the opposite direction to switch from the ON state to the OFF state, the ON / OFF locking part (143a) of the latch (143) is engaged with the latch holder (147).

[0110] That is, in a normal on / off operation by user operation, the on / off catch portion (143a) of the latch (143) is caught on the latch holder (147) and is in a restrained state. That is, during a normal on / off operation, it moves between the states of FIG. 10 and FIG. 11.

[0111] Next, we will examine the trip operation. First, we will look at the overcurrent trip process.

[0112] When the bimetal (161) of the tripping part (150) bends due to heat generated when an overcurrent flows through the circuit in an energized state as shown in FIG. 11, the shift lever (170) fitted with the bimetal (161) advances, and the pressing part (175) of the shift lever (170) rotates the latch holder (147) counterclockwise (see FIG. 13). Accordingly, the restraint on the latch (143) is released. When the restraint on the latch holder (147) is released, the latch (143) returns to its original state as the restraining force of the main spring (148) is removed. Receiving the restoring force of the main spring (148), the push link (145) rotates clockwise, and the second U-pin (144) is pulled. The latch (143) rotates counterclockwise by the second U-pin (144). At this time, the push link (145) presses the crossbar (146), so that the movable contact (113) is separated from the fixed contact (111), and the circuit is cut off. (Transition to the state of FIG. 13)

[0113] Subsequently, as the joint gear (142) rotates further counterclockwise by the restoring force of the joint gear spring (142a), the latch (143) rotates clockwise through the first U-pin (149) and returns to the Off position. (Transition to the state of FIG. 10)

[0114] Next, we will examine the short-circuit current (fault current) tripping process. We will refer further to Fig. 12. Fig. 12 shows an instantaneous tripping state.

[0115] When a short-circuit current flows through the circuit in the energized state as shown in FIG. 11, an induced electromagnetic force is generated in the instantaneous coil (157). Due to this induced electromotive force, the movable core (153) is attracted to the fixed core (152). In conjunction with the movement of the movable core (153), the instantaneous trip lever (155) rotates counterclockwise and the trip plate (156) moves downward to press the trip action part (147a) of the latch holder (147), causing the latch holder (147) to rotate counterclockwise (see FIG. 12). Accordingly, the restraint on the latch (143) is released. When the restraint on the latch holder (147) is released, the latch (143) rotates counterclockwise by the force of the main spring (148). Receiving the force of the main spring (148), the push link (145) rotates clockwise and the second U-pin (144) is pulled. The latch (143) rotates counterclockwise by the second U-pin (144). At this time, the push link (145) presses the crossbar (146), causing the movable contact (113) to be separated from the fixed contact (111), thereby blocking the circuit. The contact portion is switched to the state of FIG. 7.

[0116] Subsequently, as the joint gear (142) moves due to the restoring force of the joint gear spring (142a), the latch (143) rotates clockwise through the first U-pin (149) and returns to the Off position. (Transition to the state of FIG. 10)

[0117] Next, we will examine the test trip or forced trip action. In the energized state as shown in FIG. 11, when a user pushes the protrusion (174) of the shift lever (170) using a tool, the shift lever (170) advances and rotates the latch holder (147) counterclockwise (see FIG. 13). Accordingly, the restraint on the latch (143) is released. When the restraint on the latch holder (147) is released, the latch (143) rotates counterclockwise by the force of the main spring (148). Receiving the force of the main spring (148), the push link (145) rotates clockwise, and the second U-pin (144) is pulled. The latch (143) rotates counterclockwise by the second U-pin (144). At this time, the push link (145) presses the crossbar (146), causing the movable contact (113) to be separated from the fixed contact (111), and the circuit is cut off. At the contact point, it switches to the state of Fig. 7.

[0118] Subsequently, as the joint gear (142) moves due to the restoring force of the joint gear spring (142a), the latch (143) rotates clockwise through the first U-pin (149) and returns to the Off position. (Transition to the state of FIG. 10)

[0119] According to the trip device of a circuit breaker for motor protection according to one embodiment of the present invention, unlike the method in which a shift lever acts on a latch holder of an opening / closing mechanism through a conventional compensation bimetal, the shift lever acts directly on the latch holder without passing through a compensation bimetal, thereby reducing operating errors and improving stability.

[0120] In addition, the shift lever consists of a single component, which improves consistency and enhances productivity during operation.

[0121] In addition, production costs are reduced as the compensation bimetal and dial assembly are omitted.

[0122] The embodiments described above illustrate the best embodiments for implementing the present invention, and those skilled in the art will be able to make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, these embodiments are merely for illustrative purposes, not for limiting the technical concept of the present invention. Consequently, it should be understood that the scope of the technical concept of the present invention is not limited by these embodiments. That is, the scope of protection of the present invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention. Explanation of the symbols

[0123] 101 Upper Frame 102 middle frame 103 Lower Frame 105 Power side terminal 106 Load-side terminal section 110 contact part 111 Fixed contact 113 movable contact 120 Soho Department 140 Switching mechanism 141 handle 142 Joint Gear 143 latch 144 2nd U-pin 145 Push Links 146 crossbar 147 Latch Holder 148 Main Spring 149 1st U-pin 150 Trips 152 fixed cores 153 operating cores 154 Core Spring 155 Instant Trip Lever 156 Trip Plate 157 Instantaneous Coil 160 Terminal Load 161 bimetal 163 heater 170 shift lever 172 First Plate 173 Connection 174 protrusion 175 Pressurizing part 177 Second Plate

Claims

Claim 1 A trip device for a circuit breaker for motor protection, comprising: a latch holder that restrains a latch of an opening / closing mechanism; and a shift lever that is movably installed on a frame and moves in a forward / backward direction to allow or release the restraint of the latch holder; wherein an upper-facing upper-facing partition protrusion is formed on the upper-facing partition protrusion of the frame, and a guide projection that guides the shift lever is formed on the upper-facing partition protrusion; wherein the shift lever includes a first plate and a second plate arranged side by side, and an upwardly protruding protrusion is provided on the front portions of the first plate and the second plate, and a pressure portion protruding in the direction of the latch holder is provided on the protrusion, so that when the pressure portion is pushed forward, it contacts the latch holder and rotates the latch holder to perform a trip operation. Claim 2 delete Claim 3 A trip device for a motor protection circuit breaker according to claim 1, wherein a plurality of elongated holes into which the guide projection is inserted are formed along the longitudinal direction in the first plate and the second plate. Claim 4 In paragraph 3, the first elongated hole positioned at the front among the elongated holes is formed to be longer than the second elongated hole positioned at the rear, forming a trip device for a motor protection circuit breaker. Claim 5 delete Claim 6 A trip device for a motor protection circuit breaker according to claim 1, wherein an insertion portion into which a bimetal of a detection unit is inserted is formed in the protrusion. Claim 7 In claim 1, the first plate is a trip device for a motor protection circuit breaker in which the front portion is formed thicker than the rear portion. Claim 8 In claim 6, a trip device for a motor protection circuit breaker comprising a connecting portion connecting the first plate and the second plate. Claim 9 In claim 8, the trip device of a motor protection circuit breaker in which an insertion groove is formed in the connecting portion into which the upper end of the bimetal is inserted. Claim 10 delete

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