Motor protector

Abstract

A motor protector according to an embodiment of the present invention comprises an airtight container, two conductive terminal pins, two fixed contact support bodies, two fixed contacts, two movable contacts, and a thermally sensitive plate. The fixed contact support body is formed by bending a sheet material to integrally comprise: a conductive terminal pin-side region; a fixed contact-side region disposed across a space region and provided with fixed contacts; and a connection region extending across the space region and connecting the conductive terminal pin-side region and the fixed contact-side region. The combined width of the connection region is set to be smaller than the combined width of the space region.

Description

Technical Field

[0001] An embodiment of the present invention relates to a motor protector. Background Art

[0002] Various motor protectors have been proposed for protecting electric motors, particularly three-phase motors, built into hermetic electric compressors from burnout. These motor protectors are connected to the neutral point of a three-phase star connection within the hermetic electric compressor. The motor protector includes a thermal plate that activates due to the ambient temperature within the compressor or heat generated by the current flowing through the motor protector. This activation of the thermal plate interrupts the circuit, blocking power to all windings of the motor.

[0003] Here, the state in which one or more phases of the three-phase power supply to the motor are not energized due to a broken power line, poor contact at the wire connection or control switch, or a broken wire inside the motor is called "phase loss." When starting a compressor, if the motor is energized in the phase loss state, it will enter a locked state where the motor rotor does not rotate due to insufficient torque, and the starting current will continue to flow through the motor. Since the starting current is larger than the operating current, if the starting current continues to flow through the motor in the phase loss state, the phases at the neutral point will lose balance, causing an abnormal current to flow. Generally, the starting current when the motor is about to start from this phase loss state is called the "phase loss locking current."

[0004] If the rotor locks due to a phase loss, the flow of refrigerant, refrigerator oil, or lubricant will no longer cool the motor. Furthermore, if the phase loss lock current continues to flow through the motor while the rotor remains locked, the motor's temperature rises rapidly due to Joule heating, potentially causing the motor to burn out in the worst case. Therefore, it is important to detect the phase loss lock current and shut off power to the motor.

[0005] However, if the compressor's rated output is low, meaning the motor's rated current is low, the phase-locking current also decreases. Furthermore, a low phase-locking current also reduces the Joule heat generated by the current, requiring time for the temperature within the motor protector to rise. Consequently, if phase-locking occurs, the thermal plate cannot be quickly heated to operating temperature. Consequently, it takes time for the motor protector to operate and interrupt the phase-locking current. During this time, the motor temperature may rise to dangerous levels.

[0006] In this case, one method to shorten the time until shutdown is to lower the operating temperature of the thermal plate. However, motor protectors provide not only overcurrent protection but also overheat protection. Therefore, to ensure the overheat protection characteristics of the motor protector, the operating temperature of the thermal plate must be set to a level where it will not operate under the heat generated during normal compressor operation. Therefore, simply lowering the operating temperature of the thermal plate would compromise the overheat protection characteristics.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 2002-352685. Summary of the Invention

[0010] Problems to be solved by the invention

[0011] The present embodiment has been made in view of the above circumstances, and an object thereof is to provide a motor protector that can respond in a short time even to a relatively small phase loss lockout current without sacrificing overheat protection characteristics.

[0012] Solutions for solving problems

[0013] The motor protector of this embodiment comprises: an airtight container having an outer shell formed in a dome shape and a cover plate provided at the end of the opening side of the outer shell, and being airtightly constructed; two conductive terminal pins, which penetrate the cover plate and are provided in the airtight container, one end of which is inserted into the interior of the airtight container and the other end of which is exposed to the outside of the airtight container; two fixed contact support bodies, which correspond to each of the conductive terminal pins and are provided in the interior of the airtight container, one end of which is fixed to the end of the conductive terminal pin; two fixed contacts, which are provided in the interior of the airtight container and are provided at the two ends. The fixed contact support body includes an end opposite to the end on which the conductive terminal pin is provided; two movable contacts, which are provided inside the airtight container and correspond to the two fixed contacts; and a heat-sensitive plate, which is provided inside the airtight container and is equipped with the two movable contacts. When the movable contacts are not in operation, the movable contacts are brought into contact with the fixed contacts to close the two fixed contacts. When the ambient temperature inside the airtight container reaches a specified temperature and the device is in operation, the movable contacts are deformed in a direction away from the fixed contacts to open the fixed contacts. The fixed contact support body is formed by bending a plate material to integrally include: a conductive terminal pin side region, on which the conductive terminal pin is provided; a fixed contact side region, which is arranged with a space region formed by passing through the fixed contact support body between the conductive terminal pin side region and the fixed contact; and a connection region, which is provided across the space region and connects the conductive terminal pin side region and the fixed contact side region. The total width of the connection region is set to be smaller than the total width of the space region. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is an external view showing an example of a motor protector according to one embodiment.

[0015] Figure 2 This is a cross-sectional view showing an example of a motor protector according to one embodiment.

[0016] Figure 3 An example of an embodiment of a motor protector is along Figure 2 A cross-sectional view taken along line X3-X3.

[0017] Figure 4 This is an exploded perspective view showing an example of a motor protector according to one embodiment with a case removed.

[0018] Figure 5 This is a plan view showing an example of a motor protector according to one embodiment, with a case and a movable contact mechanism removed.

[0019] Figure 6 This is an enlarged view showing a portion of a fixed contact mechanism of an example of a motor protector according to an embodiment.

[0020] Figure 7 An example of an embodiment of a motor protector is along Figure 6 A cross-sectional view taken along the X7-X7 line.

[0021] Figure 8 An example of a motor protector according to an embodiment is shown in an enlarged manner. Figure 7 An enlarged view of the X8 portion.

[0022] Figure 9 This is a plan view showing an example of a fixed contact support body of an example of a motor protector according to an embodiment.

[0023] Figure 10 An example of an embodiment of a motor protector is along Figure 9 Cross-sectional view taken along the X10-X10 line.

[0024] Figure 11 This is a development view showing a state before bending of a fixed contact support body of an example of a motor protector according to an embodiment.

[0025] Figure 12 This is a plan view showing an example of a spacer as an example of a motor protector according to an embodiment.

[0026] Figure 13 An example of an embodiment of a motor protector is along Figure 12 Cross-sectional view taken along line X13-X13.

[0027] Figure 14 An example of an embodiment of a motor protector is along Figure 12 A cross-sectional view taken along the X14-X14 line.

[0028] Figure 15 This is a plan view (part 1) illustrating an example of a method of attaching a spacer of an example of a motor protector according to an embodiment.

[0029] Figure 16 An example of an embodiment of a motor protector is along Figure 15 Cross-sectional view taken along the X16-X16 line.

[0030] Figure 17 This is a plan view (part 2) showing an example of a process of attaching a spacer of an example of a motor protector according to an embodiment.

[0031] Figure 18 This is a diagram schematically showing an example of a connection state when a motor protector according to an embodiment is applied to a three-phase motor. DETAILED DESCRIPTION

[0032] Hereinafter, one embodiment of a motor protector to which the present invention is applied will be described with reference to the drawings. Figure 1 The motor protector 10 shown in FIG. 1 is suitable for a motor, particularly a three-phase motor, built into a hermetic electric compressor used in, for example, an air conditioner, etc. The motor protector 10 is used by being connected to the neutral point of the three-phase motor, for example.

[0033] When a specified abnormal current flows through the motor protector 10 and generates heat, or when the motor itself generates heat due to some abnormality, resulting in the ambient temperature rising to a specified temperature, the motor protector 10 operates to disconnect the circuit. Thus, the motor protector 10 has the function of cutting off the neutral point of the three-phase motor and blocking the power supply to all the windings of the motor. Figures 2 to 4 As shown, the motor protector 10 includes an airtight container 20, a movable contact mechanism 30, two conductive terminal pins 40, and a fixed contact mechanism 50. The movable contact mechanism 30 and the fixed contact mechanism 50 are both disposed within the airtight container 20.

[0034] The airtight container 20 forms the outer shell of the motor protector 10 and is configured to be airtight and watertight. Figure 2 As shown in FIG. 1 , the airtight container 20 includes a housing 21 and a cover 22. The housing 21 is made of, for example, metal and has a dome-shaped elongated shape with one end open. The cover 22 is a plate-shaped member made of, for example, metal and is formed to conform to the opening of the housing 21. The cover 22 is fixed to the end of the housing 21 on the opening side by welding around its entire circumference, thereby sealing the opening of the housing 21 in an airtight and watertight manner.

[0035] The movable contact mechanism 30 has a function of operating to cut off the electrical connection with the fixed contact mechanism 50 when the ambient temperature inside the airtight container 20 reaches a predetermined temperature or above. Figure 4 As shown, the movable contact mechanism 30 includes a heat-sensitive plate support 31 , a heat-sensitive plate 32 , two movable contacts 33 , a fixing piece 34 , an elastic plate 35 , a pressing piece 36 , a stopper 37 , and an insertion piece 38 .

[0036] The thermal plate support 31 is fixed to the inner side surface of the housing 21 and has the function of supporting the thermal plate 32. The thermal plate support 31 is formed by bending, for example, a rigid, long metal plate. The thermal plate support 31 is formed into a shape that is symmetrical about the center of the longitudinal direction. The thermal plate support 31 has two fixing portions 311. The fixing portions 311 are formed by bending the two ends of the thermal plate support 31 so as to be parallel to the inner side surface of the housing 21. The fixing portions 311 are fixed to the inner surface of the housing 21 by welding or the like. In addition, the thermal plate support 31 is formed into a shape that does not interfere with the elastic plate 35 or the pressing piece 36.

[0037] The thermosensitive plate 32 has a function of moving the movable contact 33 when the ambient temperature in the airtight container 20 reaches a predetermined temperature or above, that is, when the temperature of the thermosensitive plate 32 reaches a predetermined temperature or above. The thermosensitive plate 32 is a member formed by drawing a thin conductive bimetal or trimetal into a shallow disk shape. The thermosensitive plate 32 is formed into an elliptical shape that is long in the longitudinal direction of the motor protector 10 as a whole. The two movable contacts 33 are respectively provided on the surface of the cover plate 22 side at the two ends of the elliptical shape of the thermosensitive plate 32 by welding or the like. The thermosensitive plate 32 has a fixing portion 321. The fixing portion 321 is formed so that the central portion of the thermosensitive plate 32 in the longitudinal direction protrudes outward in a roughly rectangular shape in the width direction of the thermosensitive plate 32. A fixing piece 34 is provided on the surface of the cover plate 22 side of the fixing portion 321 by welding or the like.

[0038] When the heat-sensitive plate 32 is not in operation, each movable contact 33 is kept in contact with a fixed contact 51, which will be described later, thereby closing the two fixed contacts 51. Furthermore, when the ambient temperature inside the airtight container 20 reaches a predetermined temperature, the heat-sensitive plate 32 is activated, thereby deforming each movable contact 33 away from each fixed contact 51, thereby opening the fixed contacts 51.

[0039] like Figure 2 As shown in FIG. 1 , with the center of the heat-sensitive plate 32 in the longitudinal direction as the vertex, the two longitudinal end sides, i.e., the two movable contacts 33, are bent toward the cover plate 22. Then, when the ambient temperature in the airtight container 20 reaches a predetermined temperature, the bending direction of the heat-sensitive plate 32 is reversed, and the movable contacts 33 move away from the cover plate 22.

[0040] The heat-sensitive plate 32 is fixed to the elastic plate 35 via a fixing piece 34. The fixing piece 34 is formed by, for example, bending a metal plate. The center portion of the fixing piece 34 on the side opposite the cover plate 22 is fixed to the fixing portion 321 of the heat-sensitive plate 32 by welding, etc., and the ends of the fixing piece 34 are fixed to the mounting portion 351 of the elastic plate 35 by welding, etc.

[0041] The movable contacts 33 are made of, for example, a conductive metal material or a coating material such as silver oxide and copper or a copper alloy. The two movable contacts 33 are positioned opposite the two fixed contacts 51 described later relative to the thermal plate 32. The movable contacts 33 are formed into a substantially hemispherical shape that protrudes from the surface of the thermal plate 32 on the cover plate 22 side toward the cover plate 22.

[0042] The elastic plate 35 elastically supports the thermally sensitive plate 32 via the fixing piece 34. The elastic plate 35 is made of, for example, a thin, elastically deformable metal plate. It has a generally elliptical shape with a long, hole-shaped opening formed in the center. The elastic plate 35 has two mounting portions 351 protruding from the longitudinal center of the elliptical shape. The mounting portions 341 of the fixing piece 34 are fixed to the mounting portions 351 of the elastic plate 35 by welding or other means. This elastically connects the thermally sensitive plate 32 to the elastic plate 35 via the fixing piece 34.

[0043] Furthermore, the heat-sensitive plate support 31 is fixed to the central portion of the motor protector 10 in the longitudinal direction and on the opposite side of the mounting portion 351 in the width direction by welding or the like. Figure 2 As shown, when viewed in the longitudinal direction of the motor protector 10 , the elastic plate 35 is supported by the heat-sensitive plate support 31 in a double cantilever beam state with the center portion in the longitudinal direction as a fulcrum.

[0044] In addition, if Figure 3 As shown, when viewed in the width direction of the motor protector 10, the elastic plate 35 is supported on the thermal plate support 31 in a cantilevered configuration, with one side in the width direction being a fixed end and the other side being a free end. Thus, even if, for example, the thermal plate 32 is arranged slightly tilted relative to the cover plate 22, i.e., the two fixed contacts 51 described later, the elastic force of the elastic plate 35 can balance the pressing forces acting on the two movable contacts 33. In other words, any deviation in contact pressure between the two movable contacts 33 can be absorbed, resulting in a uniform contact pressure.

[0045] The pressing piece 36 is used to calibrate the operating temperature of the motor protector 10. The pressing piece 36 is, for example, a sufficiently rigid metal member formed into a shape elongated in the width direction of the motor protector 10. The pressing piece 36 is located in the longitudinal center of the motor protector 10. One longitudinal end of the pressing piece 36 is fixed to the inner surface of the housing 21 by welding or other means. Furthermore, when the thermal plate 32 is not operating, the other longitudinal end of the pressing piece 36 contacts the curved apex of the thermal plate 32, exerting a pressing force.

[0046] The temperature calibration of the motor protector 10 is performed in the following manner: the various components are assembled in the airtight container 20, the outer shell 21 and the cover plate 22 are welded to complete the airtight container 20, and then the portion of the outer shell 21 provided with the pressing piece 36 is pressed and deformed. When the portion of the outer shell 21 corresponding to the pressing piece 36 is pressed into the inner side of the airtight container 20, the pressing piece 36 moves toward the cover plate 22, the central portion of the thermal plate 32 is pressed, and the curved shape of the thermal plate 32 is deformed. By pressing and deforming the portion of the outer shell 21 provided with the pressing piece 36 in this way, the thermal plate 32 can be adjusted to deform at a desired temperature.

[0047] like Figure 3 As shown, the baffle 37 is composed of, for example, an L-shaped metal member and is provided at the center of the longitudinal direction of the cover plate 22, facing the fixing piece 34. When the elastic plate 35 bends toward the cover plate 22 to a predetermined amount about the connection portion with the heat-sensitive plate support 31 as a fulcrum, it contacts the baffle 37 via the fixing piece 34. Thus, the baffle 37 prevents the elastic plate 35 and the heat-sensitive plate 32 from bending beyond a predetermined amount.

[0048] like Figure 4 As shown, the insertion piece 38 is formed by bending a sheet-like member having, for example, electrical insulation into a U-shape. The insertion piece 38 is inserted between the thermal plate 32 and the pressing piece 36, and between the fixing piece 34 and the baffle 37. The insertion piece 38 has the function of preventing bypass current from flowing between the thermal plate 32 and the baffle 37 via the fixing piece 34, and between the thermal plate 32 and the pressing piece 36. The insertion piece 38 is preferably a member having electrical insulation, heat resistance, strength, and flexibility, such as polyamide paper, but is not limited thereto. In addition, as long as the above-mentioned bypass current does not substantially cause a problem, the insertion piece 38 can be omitted, or a structure in which the insertion piece 38 is only inserted between the thermal plate 32 and the pressing piece 36, or between the fixing piece 34 and the baffle 37 can be adopted.

[0049] The conductive terminal pins 40 are made of a conductive member such as metal and are, for example, formed into a cylindrical rod shape. The two conductive terminal pins 40 are respectively inserted through holes 221 formed in the cover plate 22 and mounted on the cover plate 22, with one end inserted into the interior of the airtight container 20 and the other end exposed outside the airtight container 20. An electrically insulating filler material 231, such as glass, is provided between the inner side of the hole 221 and the conductive terminal pins 40. As a result, the conductive terminal pins 40 are fixed to the cover plate 22 in an electrically insulated state and in an airtight and watertight manner.

[0050] The fixed contact mechanism 50 is disposed within the airtight container 20 and includes two fixed contacts 51, two fixed contact supports 60, and two spacers 70. Each fixed contact 51, each fixed contact support 60, and each spacer 70 constitutes a set. The two sets of fixed contacts 51, fixed contact supports 60, and spacers 70 correspond to the conductive terminal pins 40, respectively, and are symmetrically arranged relative to the cover plate 22.

[0051] The fixed contacts 51 are made of, for example, a conductive metal material or a coating material such as silver oxide and copper or a copper alloy. The two fixed contacts 51 are fixed by welding or the like to the end of the fixed contact support 60 opposite to the end on which the conductive terminal pin 40 is provided and to the surface opposite to the surface on which the conductive terminal pin 40 is provided.

[0052] The fixed contact support 60 electrically connects the conductive terminal pin 40 and the fixed contact 51. The fixed contact support 60 is made of a conductive plate material, such as a metal plate. One end of the fixed contact support 60 is fixed to the end of the conductive terminal pin 40 located inside the airtight container 20, for example, by welding. Furthermore, the fixed contact 51 is provided at the other end of the fixed contact support 60.

[0053] In this case, when the thermal plate 32 is not operating, each fixed contact 51 is in contact with the opposing movable contact 33. Therefore, in this case, electrical conduction is established between the two fixed contacts 51 via the movable contact 33 and the thermal plate 32. In other words, in this case, the two conductive terminal pins 40 are electrically connected via the fixed contact support 60, the fixed contacts 51, the movable contact 33, and the thermal plate 32.

[0054] For example, Figure 9 As shown, the fixed contact support 60 is formed symmetrically about a line extending in the longitudinal direction and passing through the center of the fixed contact support 60 in the width direction. The conductive terminal pin 40 is fixed to one end of the fixed contact support 60 by welding, for example, while the fixed contact 51 is fixed to the other end by welding, for example. In this configuration, the fixed contact support 60 is in a cantilevered state, with the end on the side with the conductive terminal pin 40 serving as the fixed end and the end on the side with the fixed contact 51 serving as the free end. Therefore, the free end of the fixed contact support 60, where the fixed contact 51 is located, can swing with the fixed end on the side with the conductive terminal pin 40 serving as the fulcrum.

[0055] like Figures 6 to 9As shown, the fixed contact support 60 includes a conductive terminal pin side region 61, a fixed contact side region 62, and a connection region 63. The conductive terminal pin side region 61 is a region where the end of the conductive terminal pin 40 is disposed and is located closer to the conductive terminal pin 40 than the fixed contact side region 62. The fixed contact side region 62 is a region where the fixed contact 51 is disposed and is located closer to the fixed contact 51 than the conductive terminal pin side region 61.

[0056] The following, such as Figure 6 As shown, the direction in which the conductive terminal pin side region 61 and the fixed contact side region 62 are connected to each other is defined as the length direction of the fixed contact support 60, and the direction perpendicular to the length direction and parallel to the cover plate 22 is defined as the width direction of the fixed contact support 60. Furthermore, the length direction and width direction of the fixed contact support 60 are consistent with the length direction and width direction of the motor protector 10 when viewed from above.

[0057] The conductive terminal pin side region 61 integrally comprises a semicircular portion 611, a trapezoidal portion 612, a rectangular portion 613, and at least one protrusion 614, in this case, two protrusions 614. In this specification, "integrally" refers to a seamless structure formed through sheet metal processing, various molding processes, etc. Within the conductive terminal pin side region 61, the semicircular portion 611, the trapezoidal portion 612, the rectangular portion 613, and the two protrusions 614 are arranged in this order from the conductive terminal pin 40 side toward the fixed contact 51 side.

[0058] The semicircular portion 611 is formed into a roughly semicircular shape that is flat and bulges toward the opposite side of the fixed contact 51. The radius of the semicircular portion 611 is larger than the radius of the conductive terminal pin 40. The end of the conductive terminal pin 40 is fixed to the central part of the semicircular portion 611. The trapezoidal portion 612 is formed into a flat trapezoidal shape that widens toward the rectangular portion 613 side, that is, the fixed contact side area 62 side. That is, the trapezoidal portion 612 is configured such that the boundary portion between the semicircular portion 611 and the trapezoidal portion 612 serves as the upper base of the trapezoidal portion 612, and the boundary portion between the trapezoidal portion 612 and the rectangular portion 613 serves as the lower base of the trapezoidal portion 612. Moreover, in the trapezoidal portion 612, the lower base is set to be longer than the upper base. In addition, the trapezoidal portion 612 is connected between the semicircular portion 611 and the rectangular portion 613, forming an inclined surface that descends from the semicircular portion 611 toward the rectangular portion 613 side.

[0059] The rectangular portion 613 is formed into a flat, generally rectangular shape that is elongated in the width direction of the fixed contact support 60. The rectangular portion 613 is located closer to the cover plate 22 than the semicircular portion 611. Two protrusions 614 are provided, each protruding in a generally semicircular shape from the edge of the rectangular portion 613 toward the fixed contact 51. The two protrusions 614 are spaced apart from each other in the longitudinal direction of the rectangular portion 613, i.e., the width direction of the fixed contact support 60. The protrusions 614 are formed on the same surface as the rectangular portion 613.

[0060] The fixed contact side region 62 is the area where the fixed contacts 51 are located. It is formed so that the center portion of the fixed contact support 60 in the width direction is bulged into a circular shape. Furthermore, the fixed contact side region 62 includes a circular portion 621 and side portions 622. The circular portion 621 is formed so that the center portion of the fixed contact support 60 in the width direction is bulged into a circular shape in the fixed contact side region 62. The side portions 622 are located on either side of the circular portion 621 in the width direction of the fixed contact support 60. The length of the side portions 622 in the length direction of the fixed contact support 60 is smaller than the length of the circular portion 621 in the length direction of the fixed contact support 60. In other words, in the fixed contact side region 62, the length of the fixed contact support 60 in the width direction is smaller at the two end portions than at the center portion of the fixed contact support 60 in the width direction.

[0061] The fixed contact side region 62 is arranged with a space region 64 sandwiched between it and the conductive terminal pin side region 61. The space region 64 is a hole or cutout formed through the fixed contact support 60 in the thickness direction. In this embodiment, the space region 64 is formed by a hole formed through the fixed contact support 60 in the thickness direction. The fixed contact side region 62 is formed on the same surface as the rectangular portion 613 and the protruding portion 614. In this embodiment, the space region 64 is formed across the entire width of the fixed contact support 60. In other words, the conductive terminal pin side region 61 and the fixed contact side region 62 do not contact each other.

[0062] In this case, the shortest distance between the conductive terminal pin side region 61 and the fixed contact side region 62, including the protrusion 614 and the circular portion 621, is set to a distance that prevents short circuits even when a phase-loss lockout current flows. In other words, a distance is maintained between the rectangular portion 613 and the protrusion 614, which form part of the conductive terminal pin side region 61, and the circular portion 621, which forms part of the fixed contact side region 62, to prevent short circuits even when a phase-loss lockout current flows through the fixed contact support 60.

[0063] The connection region 63 is provided across the space region 64 and connects the conductive terminal pin side region 61 and the fixed contact side region 62. The connection region 63 is formed into a rectangular shape that is long in the longitudinal direction of the fixed contact support 60, and connects the two end side portions of the rectangular portion 613 in the width direction of the fixed contact support 60 and the two end side portions, i.e., the side portions 622, of the fixed contact side region 62 in the width direction of the fixed contact support 60.

[0064] In this embodiment, the connection regions 63 are provided on both sides of the space region 64 in the width direction of the fixed contact support 60. That is, the fixed contact support 60 has two connection regions 63 provided at both ends in the width direction of the fixed contact support 60. Furthermore, in this embodiment, the conductive terminal pin side region 61 and the fixed contact side region 62 are physically and electrically connected only via the two connection regions 63 provided at both ends in the width direction of the fixed contact support 60.

[0065] In this case, a spatial region 64 exists on the straight line connecting the conductive terminal pin 40 and the fixed contact 51 along the surface of the fixed contact support 60. Therefore, the current flowing between the conductive terminal pin 40 and the fixed contact 51 does not flow through the path connecting the conductive terminal pin 40 and the fixed contact 51 in the straight line, but rather flows through a path that bypasses the spatial region 64, that is, the connection region 63.

[0066] In addition, in this embodiment, if Figure 9 and Figure 10 As shown, the sum of the width dimensions L1 of the two connection regions 63, i.e., 2×L1, is set smaller than the sum of the width dimensions L2 of the space region 64 (in this case, L2). In other words, in this embodiment, the relationship between the sum of the width dimensions 2×L1 of the connection regions 63 and the sum of the width dimensions L2 of the space region 64 is 2×L1<L2.

[0067] Furthermore, in this embodiment, the total widthwise dimensions of the connection regions 63 (2×L1) are greater than ¼ of the total widthwise dimensions of the space regions 64 (L2), but less than ½ of the total widthwise dimensions of the space regions 64 (L2). In other words, in this case, the relationship between the total widthwise dimensions of the connection regions 63 (2×L1) and the total widthwise dimensions of the space regions 64 (L2) is L2 / 4 < 2×L1 < L2 / 2. Specifically, in this embodiment, the total widthwise dimensions of the two connection regions 63 (2×L1) are set to approximately ¾ of the total widthwise dimensions of the space regions 64 (L2). Alternatively, the connection regions 63 may be provided only on one side of the fixed contact support 60 in the widthwise direction.

[0068] In addition, the two connection areas 63 are formed by bending the conductive terminal pin side area 61 and the fixed contact side area 62 toward the movable contact 33 side. In this case, the two connection areas 63 are bent about 90° toward the movable contact 33 side at right angles to the conductive terminal pin side area 61 and the fixed contact side area 62. As a result, compared with the case where the connection areas 63 are not bent, the fixed contact support body 60 can have high rigidity, and in particular, can improve the rigidity in the direction of bending with the portion connected to the conductive terminal pin 40 as a fulcrum. In other words, the two connection areas 63 function as reinforcements or ribs that strengthen the fixed contact support body 60. And, in this case, the connection areas 63 are only Figure 11 The boundary c1 with the conductive terminal pin side region 61 and the boundary c2 with the fixed contact side region 62 are bent at approximately 90°.

[0069] In this case, if Figure 8 As shown, the edge 631 of the connection region 63 is located closer to the thermally sensitive plate 32 than the top 511 of the fixed contact 51. That is, the distance between the edge 631 of the connection region 63 and the thermally sensitive plate 32 is closer than the distance between the top 511 of the fixed contact 51 and the thermally sensitive plate 32. In other words, the distance H1 from the surface of the cover plate 22 to the edge 631 of the connection region 63 is greater than the distance H2 from the surface of the cover plate 22 to the top 511 of the fixed contact 51.

[0070] In this embodiment, the fixed contact support 60 is Figure 11 The flat plate shown is subjected to bending processing, such as Figure 6 As shown in FIG. 1 , the conductive terminal pin side region 61, the fixed contact side region 62 and the connection region 63 are integrally formed. Figure 11 As shown, the fixed contact support body 60 before bending is formed by stamping a flat plate material using a die corresponding to the space area 64, thereby forming regions corresponding to the conductive terminal pin side region 61, the fixed contact side region 62, and the connection region 63. Then, the dotted line portion a is bent in a mountain fold of approximately 30°, the two-dot chain line portion b is bent in a valley fold of approximately 30°, and the two-dot chain lines c1 and c2 are further bent in a valley fold of approximately 90°, thereby completing the fixed contact support body 60.

[0071] The spacer 70 is positioned between the fixed contact support 60 and the cover plate 22, and serves a so-called positioning function, regulating the distance between the fixed contact support 60 and the cover plate 22. The spacer 70 is made of an electrically insulating material, such as ceramic, and provides electrical insulation between the fixed contact support 60 and the cover plate 22. Using a material such as alumina ceramic, which has excellent thermal conductivity, for the spacer 70 allows heat generated when an arc occurs in the fixed contact support 60 or the fixed contact 51 to be efficiently transferred to the cover plate 22 via the spacer 70, where it can be dissipated from the cover plate 22 to the outside. This reduces wear on the fixed contact 51 and extends the life of the motor protector 10.

[0072] like Figure 12 、 Figure 13 and Figure 14 As shown, the spacer 70 is formed into a plate-like shape that is generally elliptical. In addition, the spacer 70 has an inclined surface 71, a receiving portion 72, and a protrusion 73. The inclined surface 71 is provided on the surface of one side of the spacer 70, and is provided on both sides in the width direction relative to a center line that passes through the center of the width direction of the spacer 70 and extends in the length direction of the spacer 70. The inclined surface 71 is a surface that is inclined from the center portion in the width direction of the spacer 70 toward both end sides. In this case, as shown in FIG. Figure 14 As shown, the spacer 70 is thickest at the center in the width direction and becomes thinner toward both ends in the width direction.

[0073] The receiving portion 72 is located in the center of the width direction of the spacer 70, with one end in the longitudinal direction recessed into an arc shape. The diameter of the receiving portion 72 is set slightly larger than the diameter of the conductive terminal pin 40. As a result, a portion of the conductive terminal pin 40 can be inserted and received within the receiving portion 72.

[0074] The protrusion 73 is located at the center of the spacer 70 in the width direction and at the end opposite the receiving portion 72 in the longitudinal direction. The protrusion 73 is formed to project cylindrically from the surface of the spacer 70 facing the cover plate 22 toward the cover plate 22. When viewed from above, the protrusion 73 is located at a position that overlaps with the fixed contact 51. In this case, the cover plate 22 is formed with a recess 222 into which the protrusion 73 can be inserted in a position facing the protrusion 73. The depth of the recess 222 is slightly greater than the projection dimension of the protrusion 73.

[0075] like Figure 7As shown, with a portion of the conductive terminal pin 40 inserted into the inner side of the receiving portion 72 and the protrusion 73 inserted into the recess 222 of the cover plate 22, the spacer 70 is sandwiched between the cover plate 22 and the fixed contact support 60 and secured. The spacer 70 is pressed against the cover plate 22 by the elastic force of the fixed contact support 60 and secured. In other words, the spacer 70 of this embodiment is not secured by welding, bonding, or fastening components. Therefore, in this embodiment, the spacer 70 can be attached to and detached from the cover plate 22.

[0076] Furthermore, the spacer 70 is not limited to the above-described structure and can also be configured to be non-detachable from the cover plate 22. In this case, the spacer 70 can be installed as follows. Specifically, in this case, the spacer 70 has a hole through which the conductive terminal pin 40 can pass. The conductive terminal pin 40 is then inserted into the cover plate 22 through the hole in the spacer 70, and then the fixed contact support 60 and the conductive terminal pin 40 are welded.

[0077] In this embodiment, by inserting a portion of the conductive terminal pin 40 into the inner side of the receiving portion 72 and inserting the protrusion 73 into the recess 222 of the cover 22, the spacer 70 is restricted from moving in the direction of the surface of the cover 22. In other words, the receiving portion 72 and the protrusion 73 function to restrict the movement of the spacer 70 in the direction of the surface of the cover 22. Furthermore, by receiving the pressing force from the fixed contact support 60, the spacer 70 is restricted from moving away from the cover 22. In other words, the fixed contact support 60 functions to restrict the movement of the spacer 70 away from the cover 22.

[0078] In addition, if Figure 8 As shown, the fixed contact support 60 has a chamfered portion 65. The chamfered portion 65 is a portion of the fixed contact support 60 where the corners of the edge portion on the fixed contact 51 side and the spacer 70 side in the longitudinal direction are removed, and is subjected to a so-called C-chamfering process or R-chamfering process. The chamfered portion 65 is separated from both sides of the spacer 70.

[0079] like Figures 15 to 17 As shown, the spacer 70 is mounted on the cover 22. In a state where the spacer 70 is not mounted between the fixed contact support 60 and the cover 22, as shown in FIG. Figure 16 As shown, the fixed contact support 60 is slightly tilted so as to descend from the conductive terminal pin 40 side toward the fixed contact 51 side. In this state, the height dimension H3 from the surface of the cover plate 22 to the top end portion of the fixed contact support 60, that is, the chamfered portion 65, is smaller than the thickness dimension Hs of the center portion in the width direction of the spacer 70, that is, the maximum thickness dimension Hs of the spacer 70 excluding the protrusion 73.

[0080] In this state, if Figure 17As shown, the operator pushes the conductive terminal pin 40 against the inner side of the receiving portion 72, inserting the peripheral portion of the receiving portion 72 between the fixed contact support 60 and the cover 22. The operator then rotates the spacer 70 using the conductive terminal pin 40 as a fulcrum, fitting the protrusion 73 into the recess 222. As a result, the spacer 70 is substantially entirely pressed and secured by the fixed contact support 60, while its movement in the plane direction relative to the cover 22 is restricted.

[0081] According to the embodiment described above, the motor protector 10 includes an airtight container 20, two conductive terminal pins 40, two fixed contact supports 60, two fixed contacts 51, two movable contacts 33, and a heat-sensitive plate 32. The airtight container 20 has an airtight structure, including a dome-shaped housing 21 and a cover plate 22 provided at the end of the opening side of the housing 21. The two conductive terminal pins 40 are provided in the airtight container 20 through the cover plate 22, with one end inserted into the interior of the airtight container 20 and the other end exposed to the outside of the airtight container 20.

[0082] Two fixed contact support bodies 60 are provided inside the airtight container 20, corresponding to each conductive terminal pin 40. One end of the fixed contact support body 60 is fixed to the end of the conductive terminal pin 40. Two fixed contacts 51 are provided inside the airtight container 20, and are provided at the ends of the two fixed contact support bodies 60 opposite to the ends provided with the conductive terminal pin 40. Two movable contacts 33 are provided inside the airtight container 20, corresponding to the two fixed contacts 51, respectively.

[0083] Furthermore, the heat-sensitive plate 32 is disposed inside the airtight container 20 and is equipped with two movable contacts 33. When the heat-sensitive plate 32 is not operating, each movable contact 33 contacts each fixed contact 51, closing the gap between the two fixed contacts 51. Furthermore, when the ambient temperature inside the airtight container 20 reaches a predetermined temperature and the heat-sensitive plate 32 is operated, each movable contact 33 is deformed in a direction away from each fixed contact 51, thereby disconnecting the two fixed contacts 51 and breaking the circuit.

[0084] For example Figure 18As shown, a motor protector 10 of this structure is connected to the neutral point of a three-phase motor 90 for use. In this case, the power supply-side coil ends of the three-phase windings 911, 912, and 913 of the three-phase motor 90 are connected to a three-phase power supply via power supply terminals 921, 922, and 923, respectively. Furthermore, when observing the neutral-side coil ends of each winding 911, 912, and 913, two of the three-phase windings 911, 912, and 913 are connected to conductive terminal pins 40, and are electrically connected to the fixed contact 51 via the conductive terminal pins 40 and the fixed contact support 60 of the fixed contact mechanism 50. Furthermore, the remaining winding of the three-phase windings 911, 912, and 913 is connected to, for example, a metal portion outside the airtight container 20, secured to the cover 22 by welding, and is electrically connected to the movable contact 33 via the cover 22, the housing 21, and the movable contact mechanism 30.

[0085] In this structure, when the rotor of a three-phase motor 90 equipped with a motor protector 10 is locked due to starting in a phase-loss state, for example, a phase loss occurs when power is supplied to the motor winding 911 connected to the metal portion outside the airtight container 20, causing a phase loss, and a phase-loss locking current flows between the two conductive terminal pins 40. The phase-loss locking current flows from the conductive terminal pin 40 on one side through the fixed contact support 60 and the fixed contact 51, and then from the movable contact 33 on one side through the heat-sensitive plate 32, and then from the movable contact 33 on the other side through the fixed contact 51 on the other side and the fixed contact support 60 to the conductive terminal pin 40 on the other side. At this time, Joule heat is generated mainly by the phase-loss locking current passing through the fixed contact support 60, and the ambient temperature inside the airtight container 20 increases. Then, when the ambient temperature within the airtight container 20 rises to a predetermined operating temperature for the thermal plate 32, the thermal plate 32 operates and deforms in a direction that reverses the curvature of the thermal plate 32. This causes the movable contact 33 to separate from the fixed contact 51, disconnecting the two movable contacts 33. In this manner, the motor protector 10 can protect the motor by blocking power to the motor when a phase-loss lockout current is generated due to phase-loss lockout.

[0086] Here, when the phase loss lockout current is small, the Joule heat generated by the fixed contact support 60 is also small. Therefore, it takes a long time for the ambient temperature in the airtight container 20 to rise to the operating temperature of the heat-sensitive plate 32, resulting in the motor being unable to be properly protected.

[0087] Therefore, in this embodiment, the fixed contact support 60 is formed by, for example, Figure 11The metal plate shown is bent so as to integrally have a conductive terminal pin side region 61, a fixed contact side region 62, and a connection region 63. The conductive terminal pin side region 61 is a region where the conductive terminal pin 40 is provided. The fixed contact side region 62 is a region that is arranged with the conductive terminal pin side region 61 sandwiched between a space region 64 formed by penetrating the fixed contact support body 60, and is a region where the fixed contact 51 is provided. The connection region 63 is provided across the space region 64, and is a region that connects the conductive terminal pin side region 61 and the fixed contact side region 62. Moreover, as Figure 9 and Figure 10 As shown, the total width dimensions of the connection region 63 (2× L1 in this case) is set smaller than the total width dimensions of the space region 64 (L2 in this case).

[0088] Thus, when the motor enters a locked state and a phase-loss current is generated, the phase-loss locking current bypasses the space region 64 and flows through the connection region 63. This ensures that the distance the phase-loss locking current flows through the fixed contact support 60 is long. Furthermore, because the total width of the connection region 63 is set smaller than the total width of the space region 64, the resistivity of the connection region 63 can be maximized.

[0089] This improves the heat generation efficiency when the phase-loss locking current flows through the fixed contact support 60. Furthermore, even a small phase-loss locking current can efficiently heat the interior of the airtight container 20. Therefore, even without sacrificing overheat protection characteristics to lower the operating temperature of the thermal plate 32, the thermal plate 32 can be operated in a short period of time. As a result, even for motors of compressors with small discharge volumes, which conventional structures cannot adequately protect due to the small phase-loss locking current, the motor protector 10 of this embodiment can now adequately protect them.

[0090] The connection regions 63 are located on both ends of the width direction relative to the space region 64. This allows the interior of the airtight container 20 to be heated as uniformly as possible when a phase-locking current flows through the connection regions 63, causing them to heat. Consequently, the responsiveness of the heat-sensitive plate 32 can be improved.

[0091] Here, when the space region 64 is formed by penetrating the fixed contact support 60, the rigidity of the fixed contact support 60 as a whole decreases due to the portion of the space region 64 that is left vacant. Therefore, in this embodiment, the connection region 63 is formed so as to be bent toward the movable contact 33 relative to the conductive terminal pin side region 61 and the fixed contact side region 62. Thus, by bending the connection region 63 relative to the conductive terminal pin side region 61 and the fixed contact side region 62, the bending stress in the connection region 63 portion can be increased. As a result, even when the space region 64 is formed by penetrating the fixed contact support 60, the rigidity of the fixed contact support 60 as a whole can be maintained high. Thus, even when the motor protector 10 is repeatedly operated and the fixed contact support 60 is repeatedly heated, the original shape of the fixed contact support 60 can be maintained, and as a result, changes in characteristics caused by repeated operation can be suppressed.

[0092] Here, when the phase loss lock current becomes smaller, the heat generated in the connection area 63 also becomes smaller. Figure 8 As shown, the edge 631 of the connection region 63 is located closer to the thermally sensitive plate 32 than the top 511 of the fixed contact 51. Specifically, the distance H1 from the surface of the cover plate 22 to the edge 631 of the connection region 63 is greater than the distance H2 from the surface of the cover plate 22 to the top 511 of the fixed contact 51. This allows heat generated in the connection region 63 to be efficiently transferred to the thermally sensitive plate 32, enabling the thermally sensitive plate 32 to be activated in a shorter time. Consequently, the responsiveness of the motor protector 10 can be further improved.

[0093] The motor protector 10 of this embodiment also includes a spacer 70 disposed between the fixed contact support 60 and the cover plate 22. The fixed contact support 60 is fixed to the conductive terminal pin 40 in a cantilevered state, with the conductive terminal pin 40 side as the fixed end and the fixed contact 51 side as the free end. The spacer 70 is then pressed against the cover plate 22 to secure the spacer 70. Specifically, the spacer 70 is held between the fixed contact support 60 and the cover plate 22 by the elastic force of the fixed contact support 60. This allows the spacer 70 to be secured relative to the cover plate 22 without using an adhesive or the like, thereby improving workability during assembly of the spacer 70.

[0094] Here, if the edge of the fixed contact support 60's free end side, i.e., the end of the fixed contact side region 62, that faces the spacer 70, is formed at a right angle, then when the fixed contact support 60 generates heat and expands, or when this heat stops and it contracts, this right-angled edge may get caught on the surface of the spacer 70. Consequently, each repeated thermal expansion and contraction causes the position and posture of the fixed contact side region 62, i.e., the position and posture of the fixed contact 51, to change, which in turn affects the characteristics of the motor protector 10.

[0095] Therefore, in this embodiment, the fixed contact support body 60 further includes a chamfered portion 65. The chamfered portion 65 is formed by removing the corner of the edge portion on the side opposite to the conductive terminal pin 40 and on the side of the spacer 70. As a result, when the fixed contact support body 60 expands and contracts, the chamfered portion 65 prevents the end of the fixed contact side region 62 from getting stuck on the surface of the spacer 70. As a result, even in the case of repeated thermal expansion and contraction, the position and posture of the fixed contact side region 62, that is, the position and posture of the fixed contact 51, are unlikely to change. As a result, even when the motor protector 10 is repeatedly operated, stable operating characteristics can be obtained.

[0096] Furthermore, since the fixed contact support 60 includes the space region 64, the area through which the phase-loss locking current flows is smaller than in a structure without the space region 64. Consequently, the conductive terminal pin side region 61 and the fixed contact side region 62 are more susceptible to heat generation. Furthermore, since the conductive terminal pin side region 61 is in a cantilevered state with the portion connected to the conductive terminal pin 40 as a fulcrum, if the conductive terminal pin side region 61 generates heat and thermally expands, the conductive terminal pin side region 61 tilts up with the portion connected to the conductive terminal pin 40 as a fulcrum. As the conductive terminal pin side region 61 tilts up, the fixed contact side region 62, which is connected to the conductive terminal pin side region 61 via the connection region 63, also moves, resulting in difficulty in maintaining a stable position of the fixed contact 51.

[0097] In contrast, in this embodiment, the conductive terminal pin-side region 61 includes a trapezoidal portion 612 that widens toward the fixed contact-side region 62. This disperses the phase-loss lockout current flowing through the fixed contact-side region 62, suppressing heat generation in the fixed contact-side region 62, which contributes little to heating the thermal plate 32. This also suppresses expansion of the fixed contact-side region 62. Consequently, movement of the fixed contact-side region 62 is suppressed, and the position of the fixed contact 51 is stabilized.

[0098] Furthermore, the conductive terminal pin side region 61 of the fixed contact support 60 primarily functions as a spring when pressing and holding the spacer 70 against the cover 22. However, when the conductive terminal pin side region 61 reaches a high temperature due to heat generation, the spring characteristics change, making it difficult to properly press and hold the spacer 70 against the cover 22.

[0099] In contrast, according to this embodiment, it is possible to suppress heat generation in the conductive terminal pin side region 61. Thus, even when a phase-loss locking current flows, the influence on the spring characteristics of the conductive terminal pin side region 61 can be suppressed, resulting in the spacer 70 being properly pressed against the cover plate 22 and retained.

[0100] Furthermore, in this case, the boundary between the conductive terminal pin-side region 61 and the connection region 63 is subjected to bending, or plastic working. Consequently, stress generated by the plastic working remains in the boundary between the conductive terminal pin-side region 61 and the connection region 63, making this boundary susceptible to deformation due to heat. On the other hand, according to this embodiment, the trapezoidal portion 612 diffuses heat around the boundary between the conductive terminal pin-side region 61 and the connection region 63, thereby suppressing deformation caused by heat at the boundary between the conductive terminal pin-side region 61 and the connection region 63.

[0101] Here, assume that during mass production of the motor protector 10, a large number of fixed contact support bodies 60 are simultaneously manufactured using a mold or the like. Furthermore, assume that during the manufacture of the fixed contact support bodies 60, many of them are placed in a container or the like for storage and transportation. However, since the fixed contact support bodies 60 have a space 64, placing multiple fixed contact support bodies 60 in the same container will cause them to become wedged in the space 64, making it difficult to remove them one by one. As a result, workability during assembly of the fixed contact support bodies 60 may be reduced, and thus the productivity of the motor protector 10 may be reduced.

[0102] Therefore, the conductive terminal pin side region 61 has at least one protrusion 614 that projects toward the fixed contact side region 62. In this embodiment, the conductive terminal pin side region 61 has two protrusions 614. This reduces the distance between the conductive terminal pin side region 61 and the fixed contact side region 62 while ensuring the distance of the path through which the phase loss locking current flows. This makes it difficult for multiple fixed contact support bodies 60 to fit into each other's space region 64, even when placed in the same container. As a result, the workability during assembly of the fixed contact support bodies 60 can be improved, and the productivity of the motor protector 10 can be increased.

[0103] Furthermore, in this embodiment, the rectangular portion 613, the protruding portion 614, and the fixed contact side region 62 are formed on the same surface in the fixed contact support 60. Therefore, in the fixed contact support 60, the rectangular portion 613, the protruding portion 614, and the portion of the fixed contact side region 62 that faces the spacer 70 come into surface contact with the spacer 70, pressing the spacer 70 toward the cover plate 22.

[0104] In contrast, for example, the protrusions 614 can be configured to be slightly curved toward the spacer 70. In this case, the fixed contact support 60 contacts the spacer 70 at three points: the two protrusions 614 and the top end of the fixed contact-side region 62, thereby pressing the spacer 70 toward the cover plate 22. This three-point contact pattern between the fixed contact support 60 and the spacer 70 makes little difference, even if, for example, the fixed contact support 60 undergoes repeated thermal expansion and contraction. As a result, the spacer 70 can be stably held, and the position of the fixed contact 51 relative to the spacer 70 can also be kept stable.

[0105] The embodiment described above is provided as an example and is not intended to limit the scope of the invention. New embodiments may be implemented in various other ways and may be omitted, replaced, or modified without departing from the spirit of the invention. This embodiment and its modifications are included within the scope and spirit of the invention and are included within the scope of the invention described in the claims and their equivalents.

Claims

1. A motor protector comprising: An airtight container having an outer shell formed in a dome shape and a cover plate provided at an end portion of the outer shell on an opening side, the airtight container being constructed airtightly; two conductive terminal pins, which penetrate the cover plate and are disposed on the cover plate, with one end portion inserted into the interior of the airtight container and the other end portion exposed outside the airtight container; Two fixed contact support bodies, corresponding to each of the conductive terminal pins and disposed inside the airtight container, with one end portion fixed to the end portion of the conductive terminal pin; two fixed contacts disposed inside the airtight container and at ends of each of the two fixed contact supports opposite to the ends where the conductive terminal pins are disposed; two movable contacts disposed inside the airtight container and corresponding to the two fixed contacts; and The heat-sensitive plate is composed of a member different from the fixed contact support, is arranged inside the airtight container, and is equipped with two movable contacts. When not in operation, each movable contact is brought into contact with each fixed contact to close the two fixed contacts. When the ambient temperature inside the airtight container reaches a specified temperature and the heat-sensitive plate is in operation, each movable contact is deformed in a direction away from each fixed contact to open the fixed contacts. The fixed contact support is formed by bending a plate to integrally include: a conductive terminal pin side region, on which the conductive terminal pin is provided; a fixed contact side region, which is arranged with the conductive terminal pin side region with a space region formed by penetrating the fixed contact support body interposed therebetween and is provided with the fixed contact; and a connecting region that is provided across the space region and connects the conductive terminal pin side region and the fixed contact side region, The total width of the connection region is set to be smaller than the total width of the space region.

2. The motor protector according to claim 1, wherein: The connection region is provided on both end sides in the width direction of the space region.

3. The motor protector according to claim 2, wherein: The connection region is formed to be bent toward the movable contact side relative to the conductive terminal pin side region and the fixed contact side region.

4. The motor protector according to claim 3, wherein: An end portion of the connection region is located closer to the thermally sensitive plate than a top portion of the fixed contact.

5. The motor protector according to any one of claims 1 to 4, wherein: The motor protector further includes a spacer provided between the fixed contact support and the cover plate. The fixed contact support is fixed to the conductive terminal pin in a cantilevered state with the conductive terminal pin side as a fixed end and the fixed contact side as a free end. The fixed contact support presses the spacer onto the cover plate to fix the spacer.

6. The motor protector according to claim 5, wherein: The fixed contact support further includes a chamfered portion formed by removing a corner of an edge portion of the fixed contact support on a side opposite to the conductive terminal pin and on the spacer side.

7. The motor protector according to any one of claims 1 to 4, wherein: The conductive terminal pin side region has a trapezoidal portion formed in a trapezoidal shape that becomes wider toward the fixed contact side region.

8. The motor protector according to any one of claims 1 to 4, wherein: The conductive terminal pin side region has at least one protrusion that protrudes toward the fixed contact side region.

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