An automatic testing device for capacitor temperature characteristics

Abstract

The present invention discloses an automatic testing device for capacitor temperature characteristics, which relates to the technical field of capacitor performance testing. The automatic testing device for capacitor temperature characteristics comprises a test cabinet, wherein a receiving cavity is provided inside the test cabinet, wherein a capacitor to be tested is provided in the receiving cavity, and further comprises: a temperature measuring box fixedly installed in the receiving cavity; and a temperature measuring unit provided in the temperature measuring box to form a modular layered structure, wherein the detection unit comprises a surface layer, a middle layer, and a bottom layer. The present invention adopts a layered structure design of the temperature measuring unit, so that when the capacitor is heated during the test, heat is quickly transferred through the bottom layer, and the upper layer is insulated to suppress airflow, thereby having a good insulation effect. The detachable structure design of the middle layer can improve the replacement and maintenance efficiency on the one hand, and effectively increase the balance of heat conduction and fluidity on the other hand, thereby improving the temperature uniformity effect of the device heating test.

Description

Technical Field

[0001] The invention belongs to the technical field of capacitor performance testing, and in particular relates to an automatic testing device for capacitor temperature characteristics. Background Art

[0002] Capacitors are widely used components in electronic devices, and their temperature characteristics are a key indicator for evaluating capacitor quality. During capacitor manufacturing and use, temperature characteristics testing is necessary to determine the relative change in capacitance at different test temperatures relative to the base temperature, thereby assessing quality and reliability.

[0003] In the existing technology, some capacitor temperature tests are performed using a heating box. Solid particles are provided in the heating box to limit the placed capacitors and facilitate the conduction of temperature. The capacitors to be tested are buried deep in the solid particles to suppress air flow interference and ensure a static constant temperature environment for the capacitors. However, in actual use, since most of the filling materials are quartz sand particles, the thermal conductivity is low, which may lead to a large local temperature gradient during heating or cooling, an increase in the deviation between the capacitor surface temperature and the set value, and a decrease in test accuracy. For this reason, we propose an automatic testing device for capacitor temperature characteristics to solve the above-mentioned problems. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an automatic testing device for capacitor temperature characteristics that can overcome the above problems or at least partially solve the above problems.

[0005] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is: an automatic testing device for the temperature characteristics of capacitors, including a test cabinet, a accommodating cavity is provided inside the test cabinet, and the capacitor to be tested is provided in the accommodating cavity, and also includes: a temperature measuring box, fixedly installed in the accommodating cavity; a temperature measuring unit, arranged in the temperature measuring box to form a modular layered structure, wherein the detection unit includes a surface bin, a middle bin and a bottom bin; the middle bin adopts a separate detachable structure, and an adjustment component is provided on the middle bin for periodically adjusting the arrangement of the medium particles in the middle bin; a vibration component is provided on the side wall of the temperature measuring box to promote the flow of the medium in the temperature measuring unit.

[0006] Preferably, the interior of the surface bin is filled with hollow glass microbeads, which are covered with nanofiber filter membranes, and the diameter of the hollow glass microbeads is 0.1 mm.

[0007] Preferably, the middle layer is filled with mixed quartz sand and magnetic ceramic beads, the surfaces of the mixed quartz sand and the magnetic ceramic beads are provided with a nano antistatic coating, the diameter of the mixed quartz sand is 0.5-1 mm, and the diameter of the magnetic ceramic beads is 0.1 mm.

[0008] Preferably, the bottom bin is filled with ceramic ball particles and SMA particles, the diameter of the ceramic balls is 0.5 mm, and the diameter of the SMA particles is 0.5-1 mm.

[0009] Preferably, the middle warehouse includes a storage box that is slidably connected to the inner wall of the temperature measuring box, the top of the storage box is fixedly connected to a connecting block, the upper and lower surfaces of the storage box are provided with through holes, the top surface of the storage box is connected to a feed door through a hinge, the bottom surface of the storage box is fitted with a limiting ring, and the top of the storage box is fixed with a fixing ring.

[0010] Preferably, a connecting block is fixed on the top surface of the fixing ring, a limiting groove is provided on one side of the connecting block, a pull rod is slidably connected to the inner wall of the connecting block, a clamping block is fixed at one end of the pull rod, the clamping block is slidably connected in the limiting groove, an extrusion spring is fixed between the clamping block and the limiting groove, the extrusion spring is sleeved on the surface of the pull rod, and clamping grooves are provided on both side inner walls of the temperature measuring box.

[0011] Preferably, a driving unit is installed on the temperature measuring box, a storage box inner wall-mounted sensor is installed on the inner wall of the middle warehouse, and a controller is installed on the outer wall of the temperature measuring box, and the controller is electrically connected to the driving unit and the sensor.

[0012] Preferably, magnetic coils distributed at equal intervals are installed on the inner wall of the storage box, the magnetic coils are electrically connected to the controller, and the magnetic coils are adapted to the medium particles in the middle bin.

[0013] Preferably, the vibration assembly includes a card seat installed in the bottom compartment by a snap-on, the top surface of the card seat is provided with a groove, the capacitor is installed in the groove, the surface of the capacitor is provided with a fixed iron sleeve, the inner wall of the groove is embedded with an electromagnetic block, and the electromagnetic block is electrically connected to the controller through a wire.

[0014] Preferably, the test cabinet is provided with an exhaust fan, and a heat-conducting film is installed on the bottom inner wall of the temperature measuring box. One end of the heat-conducting film passes through the temperature measuring box to the outside and is electrically connected to the heating system in the test cabinet.

[0015] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0016] The present invention adopts a layered structure design by setting up a temperature measuring unit, so that when the capacitor is tested and heated, heat is quickly transferred through the bottom layer, and the upper layer is insulated to suppress airflow, which has a good insulation effect. The detachable structure design of the middle layer warehouse can improve the replacement and maintenance efficiency on the one hand, and effectively increase the balance of thermal conductivity and fluidity on the other hand, thereby improving the temperature uniformity effect of the heating test of the device.

[0017] In the present invention, through the setting of the vibration component, the particles filled in the temperature measuring box can be vibrated to loosen them, break the compaction of the particles, effectively prevent the dense agglomeration of the particles, and reduce the damage to the pins extending out of the capacitor. At the same time, through the linkage control, the capacitor buried deep in the particles can be assisted to limit and prevent it from tipping over. It is suitable for high-precision testing and industrial automation scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the attached figure:

[0019] Figure 1 This is a schematic diagram of the overall structure of an automatic testing device for capacitor temperature characteristics proposed by the present invention;

[0020] Figure 2 This is a schematic side cross-sectional view of an automatic test device for capacitor temperature characteristics proposed by the present invention;

[0021] Figure 3 This is a schematic diagram of a partial top view of the three-dimensional structure of the temperature measuring box proposed by the present invention;

[0022] Figure 4 This is a schematic side cross-sectional view of a temperature measuring box in an automatic test device for capacitor temperature characteristics proposed by the present invention;

[0023] Figure 5 The present invention proposes Figure 4 Schematic diagram of the enlarged structure of area A in the middle;

[0024] Figure 6 This is a schematic diagram of the partial three-dimensional structure of the middle-layer warehouse proposed in the present invention;

[0025] Figure 7 This is a schematic diagram of a partial cross-sectional structure of a temperature measuring box in an automatic testing device for capacitor temperature characteristics proposed by the present invention;

[0026] Figure 8 This is a schematic diagram of the partial three-dimensional structure of the capacitor and the card holder proposed in the present invention.

[0027] In the figure: 1. test cabinet; 2. accommodating cavity; 3. temperature measuring box; 41. bottom layer warehouse; 42. middle layer warehouse; 421. storage box; 422. fixing ring; 423. connecting block; 424. pulling rod; 425. clamping block; 426. extrusion spring; 427. limiting groove; 428. clamping slot; 429. through hole; 4291. feeding door; 43. surface layer warehouse; 44. limiting ring; 5. capacitor; 61. driving part; 62. controller; 63. magnetic coil; 64. sensor; 7. holder; 71. groove; 72. electromagnetic block; 73. fixed iron sleeve; 8. exhaust fan; 9. thermal conductive film. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments so that those skilled in the art can implement the invention with reference to the description.

[0029] It should be understood that terms such as “having”, “including” and “comprising” used herein do not preclude the existence or addition of one or more other elements or combinations thereof.

[0030] In the description of the present invention, the terms "horizontal", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0031] Example 1: Reference Figures 1-8 , an automatic testing device for the temperature characteristics of a capacitor, comprising a test cabinet 1, wherein the interior of the test cabinet 1 is provided with a accommodating chamber 2, in which a capacitor 5 to be tested is arranged, and further comprising: a temperature measuring box 3, fixedly installed in the accommodating chamber 2; a temperature measuring unit, arranged in the temperature measuring box 3 to form a modular layered structure, wherein the detection unit includes a surface bin 43, a middle bin 42 and a bottom bin 41; the middle bin 42 adopts a separate detachable structure, and an adjustment component is provided on the middle bin 42, for periodically adjusting the arrangement of medium particles in the middle bin 42; a vibration component, arranged on the side wall of the temperature measuring box 3, for promoting the flow of the medium in the temperature measuring unit, an exhaust fan 8 is provided on the test cabinet 1, and a heat-conducting film 9 is installed on the bottom inner wall of the temperature measuring box 3, and one end of the heat-conducting film 9 passes through the temperature measuring box 3 to the outside and is electrically connected to the heating system in the test cabinet 1.

[0032] This device mainly includes a test cabinet 1, a accommodating cavity 2, a temperature measuring box 3 and a layered detection unit. During the test, the capacitor 5 to be tested is placed in the dielectric particles of the bottom bin 41. The bottom bin 41 conducts heat quickly, the surface bin 43 keeps warm and suppresses airflow, and the vibration component dynamically controls the dielectric particles to achieve uniform heating and precise temperature measurement. The various components work together to meet the high efficiency and high precision requirements in industrial automation scenarios. The setting of the bottom bin 41 effectively shortens the heating response time, ensures that the bottom of the capacitor 5 reaches the target temperature first, and simulates the thermal stress in actual working conditions. The middle bin 42 is a detachable structure and can be disassembled separately during later maintenance, which greatly improves the efficiency of particle replacement and maintenance. The particles filled inside can be automatically arranged according to the measured temperature during the use of the device, which can effectively increase the balance of thermal conductivity and fluidity and improve the temperature uniformity effect of the device heating test. The temperature measuring box 3 is also equipped with a vibration Component, when arranging the particles in the middle bin 42, the particles filled in the temperature measuring box 3 can also be vibrated to loosen them, break the compaction of the particles, effectively prevent the dense agglomeration of the particles, and reduce damage to the pins extending from the capacitor 5. At the same time, the linkage control can assist in limiting the capacitor 5 buried deep in the particles to prevent it from tipping over. It is suitable for high-precision testing and industrial automation scenarios. During the test, the thermal conductive film 9 can heat the bottom of the bottom bin 41 after being energized, and then perform a heating and temperature rise test on the capacitor 5, wherein the capacitor 5 is pre-placed in the bottom bin 41, and then the particles in the bottom bin 41 are filled, and then the middle bin 42 is placed, and the particles in the middle bin 42 are filled, wherein the pins of the capacitor 5 pass through the middle bin 42 and extend to the upper part, and finally the particles in the surface bin 43 are filled, and the extended pins of the capacitor 5 are connected to the test interface on the test cabinet 1 through the elastic contact block to avoid affecting the detection of the capacitor 5 under the vibration state.

[0033] Example 2: Reference Figure 4 、 Figure 5 and Figure 6 , which is basically the same as Example 1, and further: the interior of the surface bin 43 is filled with hollow glass microbeads, and the hollow glass microbeads are covered with a nanofiber filter membrane, the diameter of the hollow glass microbeads is 0.1 mm, the middle bin 42 is filled with mixed quartz sand and magnetic ceramic microbeads, the surfaces of the mixed quartz sand and the magnetic ceramic microbeads are provided with a nano antistatic coating, the diameter of the mixed quartz sand is 0.5-1 mm, the diameter of the magnetic ceramic microbeads is 0.1 mm, and the bottom bin 41 is filled with ceramic ball particles and SMA particles, the diameter of the ceramic ball is 0.5 mm, and the diameter of the SMA particles is 0.5-1 mm.

[0034] Among them, the bottom layer bin 41 is filled with ceramic balls with a diameter of 0.5mm and shape memory alloy SMA particles with a diameter of 0.5-1mm. The ceramic balls have high thermal conductivity and can quickly absorb the heat of the heating system at the bottom of the temperature measuring box 3 and conduct it to the middle layer; the SMA particles undergo phase change at a specific temperature, and the micro-motion effect caused by the volume change can enhance the fluidity of the medium and assist heat diffusion. The combination of the two can achieve rapid heating of the bottom layer and uniform heat transfer, providing a stable heat source for the middle layer; the surface bin 43 is filled with hollow glass beads with a diameter of 0.1mm and covered with a nanofiber filter membrane. The hollow structure reduces thermal conductivity and forms a heat insulation layer; the nanofiber filter membrane further inhibits the diffusion of gas molecules and reduces the internal and external air Flow exchange, this layer prevents the external environment airflow from interfering with the test by limiting the upward loss of heat; the middle layer 42 is filled with mixed quartz sand with a diameter of 0.5-1mm and magnetic ceramic beads with a diameter of 0.1mm, and the surface is covered with a nano anti-static coating. The high specific heat capacity of the quartz sand enables it to have heat storage capacity and delay temperature fluctuations; the magnetic beads can be arranged in a direction under the drive of the external magnetic coil 63 to form a dynamic heat conduction path, and the top of the storage box 421 is connected to the feed door 4291 by a hinge to facilitate the filling of particles in the middle layer 42, and the side wall is provided with a through hole 429 and a card slot 428, which cooperates with the pull rod 424 and the card block 425 to realize the sliding and locking of the storage box 421 along the inner wall of the temperature measuring box 3.

[0035] It should be noted that the aperture of the through hole 429 is larger than the pin diameter of the capacitor 5, which facilitates the pin to pass through the through hole 429. Although the particles in the middle bin 42 will fall to the bottom bin 41 along the through hole 429 due to vibration, the bottom ceramic balls 5mm and SMA particles 0.5mm~1mm are mixed and can be compacted by vibration to form a stable support layer. At the same time, the SMA particles provide dynamic damping in the gap, providing more stable lateral support for the placed capacitor 5. Although some particles in the middle bin 42 will enter the bottom bin 41, subsequent maintenance can be efficiently solved through structural isolation and quick maintenance tools, taking into account both functionality and maintenance convenience, and effectively speeding up the maintenance efficiency of maintenance personnel.

[0036] The middle warehouse 42 includes a storage box 421 which is slidably connected to the inner wall of the temperature measuring box 3. The top of the storage box 421 is fixedly connected to a connecting block 423. The upper and lower surfaces of the storage box 421 are provided with through holes 429. The top surface of the storage box 421 is rotatably connected to the feed door 4291 by a hinge. The bottom surface of the storage box 421 fits the limiting ring 44. The top of the storage box 421 is fixed with a fixing ring 422. The top surface of the fixing ring 422 is fixed with a connecting block 423. A limiting groove 427 is provided on one side of the connecting block 423. The inner wall of the connecting block 423 is slidably connected to a pull rod 424. A clamping block 425 is fixed at one end of the pull rod 424. The clamping block 425 is slidably connected to the limiting groove 427. An extrusion spring 426 is fixed between the clamping block 425 and the limiting groove 427. The extrusion spring 426 is sleeved on the surface of the pull rod 424. The inner walls on both sides of the temperature measuring box 3 are provided with clamping slots 428.

[0037] When installing the middle bin 42, the bottom of the placed storage box 421 can be limited by the set limit ring 44. After placing the storage box 421, the particles in the middle bin 42 can be filled into the interior by manually opening the feed door 4291. The manually pulled pull rod 424 drives the clamping block 425 to move, and the elastic force of the extrusion spring 426 is used to squeeze it out and clamp it inside the clamping slot 428, thereby facilitating the overall clamping and limiting of the middle bin 42 inside the temperature measuring box 3 to prevent the middle bin 42 from being displaced and loosened during use, thereby ensuring the stability of the structure. On the other hand, when repairing and replacing particles, after clearing the particles in the surface bin 43, the restriction of the storage box 421 can be manually released, and the storage box 421 can be taken out for replacement and removal without the need for complete disassembly, saving maintenance time and improving work efficiency. The separate pull-out design can prevent excessive accumulation of particles from causing extrusion damage to the capacitor 5.

[0038] Example 3: Reference Figure 3 、 Figure 4 、 Figure 5 and Figure 8 , which is basically the same as Example 2, and furthermore: a driving unit 61 is installed on the temperature measuring box 3, a sensor 64 is installed on the inner wall of the storage box 421, and a controller 62 is installed on the outer wall of the temperature measuring box 3. The controller 62 is electrically connected to the driving unit 61 and the sensor 64. The inner wall of the storage box 421 is installed with magnetic coils 63 distributed at equal intervals. The magnetic coils 63 are electrically connected to the controller 62. The magnetic coils 63 are adapted to the medium particles in the middle bin 42. The vibration component includes a holder 7 installed in the bottom bin 41 by a snap. A groove 71 is provided on the top surface of the holder 7. The capacitor 5 is installed in the groove 71. A fixed iron sleeve 73 is provided on the surface of the capacitor 5. An electromagnetic block 72 is embedded in the inner wall of the groove 71. The electromagnetic block 72 is electrically connected to the controller 62 through a wire.

[0039] Among them, multiple sensors 64 are evenly distributed in the middle bin 42. The sensors 64 use commonly used NTC models for detection, monitor the temperature distribution state of the particles filled in the middle bin 42 in real time, and feed back to the controller 62. When the temperature difference exceeds the set threshold range, the controller 62 controls the drive unit 61 to start. The drive unit 61 is replaced by a vibration motor drive. The drive unit 61 drives the eccentric wheel to rotate at high speed, generating high-frequency vibration, and vibrating the multi-layer particles filled in the temperature measuring box 3. On the one hand, it can effectively prevent the internal filling of particles from being dense, maintain the flow state of the particles, and improve the flow effect of heat conduction. On the other hand, the gaps between the particles in the multiple layers are supplemented by vibration, which improves the efficiency of heat conduction and can provide good protection for the pins at the capacitor 5 to avoid extrusion damage to the pins caused by dense particles. At this time, the controller 62 can also control the magnetic coil 63 to be energized. After energization, an alternating magnetic field is generated to drive the microbeads to arrange / disperse periodically, promote heat diffusion, and improve temperature uniformity.

[0040] When the driving part 61 vibrates, the controller 62 can control the electromagnetic block 72 to pulse power, adsorb the fixed iron sleeve 73, and then fix the capacitor 5 to prevent the capacitor 5 from tipping over and displacing in the vibration state, avoiding local overheating or temperature measurement errors caused by tipping, and further improving the accuracy of temperature measurement. The fixed iron sleeve 73 is made of magnetic material. During the test and installation stage, the capacitor 5 is clamped in the groove 71 on the holder 7, which can play a preliminary limiting role on the capacitor 5 and facilitate subsequent particle filling.

[0041] It should be noted that some of the magnetic coils 63 can also be installed on the inner wall of the bottom bin 41. When some particles in the middle bin 42 fall into the bottom bin 41, the magnetic coils 63 change the distribution state of the microbead particles in the bottom bin 41, thereby improving the overall temperature uniformity effect of the device on the temperature test of the capacitor 5. Three driving parts 61 can be installed at the same time, and the other two are respectively installed on the opposite side walls of the driving part 61 and the bottom outer wall of the temperature measuring box 3, so as to achieve a better vibration effect on the particles filled inside according to actual needs.

[0042] The above embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patented invention. It should be noted that those skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention. These variations and improvements are equivalent modifications and improvements to the above embodiments based on the essential technology of the present invention and fall within the scope of protection of the present invention.

Claims

1. An automatic testing device for capacitor temperature characteristics, comprising a test cabinet (1), wherein a receiving chamber (2) is provided inside the test cabinet (1), and a capacitor (5) to be tested is provided in the receiving chamber (2), characterized in that: Also includes: A temperature measuring box (3) is fixedly installed in the accommodating cavity (2); A temperature measuring unit is arranged in the temperature measuring box (3) to form a modular layered structure, wherein the temperature measuring unit includes a surface bin (43), a middle bin (42) and a bottom bin (41); The middle layer bin (42) adopts a separate detachable structure, and an adjustment component is provided on the middle layer bin (42) for periodically adjusting the arrangement of the medium particles in the middle layer bin (42); A vibration component, arranged on a side wall of the temperature measuring box (3), for promoting the flow of the medium in the temperature measuring unit; The middle layer bin (42) is filled with mixed quartz sand and magnetic ceramic microbeads, and the surfaces of the mixed quartz sand and the magnetic ceramic microbeads are provided with a nano antistatic coating, the diameter of the mixed quartz sand is 0.5-1 mm, and the diameter of the magnetic ceramic microbeads is 0.1 mm; The middle warehouse (42) includes a storage box (421) slidably connected to the inner wall of the temperature measuring box (3), the top of the storage box (421) is fixedly connected to a connecting block (423), the upper and lower surfaces of the storage box (421) are provided with through holes (429), the top surface of the storage box (421) is rotatably connected to a feed door (4291) through a hinge, the bottom surface of the storage box (421) is fitted with a limiting ring (44), and the top of the storage box (421) is fixed with a fixing ring (422); A connecting block (423) is fixed on the top surface of the fixing ring (422), a limiting groove (427) is provided on one side of the connecting block (423), a pulling rod (424) is slidably connected to the inner wall of the connecting block (423), a clamping block (425) is fixed on one end of the pulling rod (424), the clamping block (425) is slidably connected in the limiting groove (427), an extrusion spring (426) is fixed between the clamping block (425) and the limiting groove (427), the extrusion spring (426) is sleeved on the surface of the pulling rod (424), and clamping grooves (428) are provided on the inner walls on both sides of the temperature measuring box (3).

2. The automatic testing device for capacitor temperature characteristics according to claim 1, characterized in that: The interior of the surface bin (43) is filled with hollow glass microbeads, which are covered with a nanofiber filter membrane. The diameter of the hollow glass microbeads is 0.1 mm.

3. The automatic testing device for capacitor temperature characteristics according to claim 1, characterized in that: The bottom bin (41) is filled with ceramic ball particles and SMA particles, the diameter of the ceramic balls is 0.5 mm, and the diameter of the SMA particles is 0.5-1 mm.

4. The automatic testing device for capacitor temperature characteristics according to claim 1, characterized in that: A driving unit (61) is installed on the temperature measuring box (3), a sensor (64) is installed on the inner wall of the storage box (421), and a controller (62) is installed on the outer wall of the temperature measuring box (3). The controller (62) is electrically connected to the driving unit (61) and the sensor (64).

5. The automatic testing device for capacitor temperature characteristics according to claim 4, characterized in that: The inner wall of the storage box (421) is provided with magnetic coils (63) distributed at equal intervals, the magnetic coils (63) are electrically connected to the controller (62), and the magnetic coils (63) are adapted to the medium particles in the middle bin (42).

6. The automatic testing device for capacitor temperature characteristics according to claim 5, characterized in that: The vibration assembly includes a card seat (7) installed in the bottom compartment (41) by a snap-fit, a groove (71) is provided on the top surface of the card seat (7), a capacitor (5) is installed in the groove (71), a fixed iron sleeve (73) is provided on the surface of the capacitor (5), an electromagnetic block (72) is embedded in the inner wall of the groove (71), and the electromagnetic block (72) is electrically connected to the controller (62) through a wire.

7. The automatic testing device for capacitor temperature characteristics according to claim 1, characterized in that: The test cabinet (1) is provided with an exhaust fan (8), and a heat-conducting film (9) is installed on the bottom inner wall of the temperature measuring box (3). One end of the heat-conducting film (9) passes through the temperature measuring box (3) to the outside and is electrically connected to the heating system in the test cabinet (1).

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