JP2011146240A - Circuit breaker with thermomotive type tripper, and its temperature inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit breaker having a thermomotive type tripper capable of measuring temperature of a bimetal or a member coming in contact with a bimetal with high accuracy with the use of a radiation thermometer. <P>SOLUTION: In the circuit breaker having a thermomotive type tripper in which a bimetal 2 is heated by overcurrent, the thermomotive type tripper for carrying out a tripping action between a movable contact and a fixed contact due to bending of the heated bimetal 2 is housed in a case 7, temperature of the bimetal 2 or that of a temperature measuring part 8 of a member in contact with the bimetal 2 is measured with a radiation thermometer 10 to detect action time of the thermomotive type tripper, a through-hole 9 opposed to the temperature measuring part 8 is provided at the case 7, and a reflection surface for reflecting measured wavelength light of the radiation thermometer 10 is formed on an inner peripheral surface of the through-hole 9. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a circuit breaker having a thermal trip device and a temperature inspection method thereof.

A thermal tripping device used for a circuit breaker is a device that detects an overcurrent exceeding a rating and performs tripping breakage between a movable contact and a fixed contact of a main circuit. The range of the trip characteristic when an overcurrent flows is defined by a standard such as JIS, and the product must satisfy it. However, in a thermal tripping device, variations in tripping characteristics are unavoidable due to manufacturing variations of components and materials. Therefore, a structure for adjusting the tripping characteristic is usually incorporated, and the characteristic is inspected and adjusted.
In order to inspect and adjust the tripping characteristic, it is necessary to accurately measure the characteristic value. In the thermal tripping device, the tripping characteristic is often measured by energizing a predetermined current and measuring the time (trip time) from the start of energization to the completion of tripping and the amount of bimetal displacement. On the other hand, since the curvature coefficient of bimetal is known, the amount of bimetal displacement can be obtained by measuring the bimetal temperature. Therefore, the trip characteristic can be grasped by measuring the bimetal temperature.

  In measuring the bimetal temperature, a non-contact measurement method is desirable so that the bimetal bending amount is not affected by the measurement. In the measurement using the contact-type thermometer, a load is applied to the bimetal from the outside through the probe, so that the bimetal is bent and the tripping characteristic is changed. As a non-contact temperature measurement method, a radiation thermometer incorporating an infrared absorption element is generally used.

International Publication No. WO2005 / 104159 Pamphlet

However, with the progress of miniaturization and higher density of circuit breakers, the electrodes that supply current to the circuit breakers, the trip characteristic adjustment mechanism, the trip opening mechanism, etc. are concentrated at the top of the circuit breaker. In order to inspect and adjust the trip time, it has become difficult to install a radiation thermometer for measuring the temperature of a bimetal or the like at a position where the bimetal is directly desired.
The present invention has been made to solve such a problem, and a thermal trip device capable of measuring the temperature of a bimetal or a member in contact with the bimetal with high accuracy using a radiation thermometer. It is an object of the present invention to provide a circuit breaker having the above and a temperature inspection method thereof.

    A circuit breaker having a thermal trip device according to the present invention is a thermal trip device in which a bimetal is heated by an overcurrent, and a tripping operation between a movable contact and a fixed contact is performed by the curvature of the heated bimetal. Is a circuit having a thermal trip device in which the temperature of the temperature measuring portion of the bimetal or a member in contact with the bimetal is measured with a radiation thermometer and the operating time of the thermal trip device is inspected In the circuit breaker, a through-hole facing the temperature measurement unit is provided in the casing, and a reflection surface for reflecting the measurement wavelength light of the radiation thermometer is formed on an inner peripheral surface of the through-hole.

Further, in the circuit breaker temperature inspection method having the thermal tripping device according to the present invention, the bimetal is heated by overcurrent, and the tripping operation between the movable contact and the fixed contact is performed by the curvature of the heated bimetal. A thermal type in which a thermal trip device is housed in a housing, the temperature of the temperature measuring part of the bimetal or a member in contact with the bimetal is measured with a radiation thermometer, and the operating time of the thermal trip device is inspected In the circuit breaker temperature inspection method having a tripping device, a through hole facing the temperature measurement unit is provided in the housing, and the reflection of the measurement wavelength light of the radiation thermometer reflected on the inner peripheral surface of the through hole Forming a surface, and receiving the radiated light including the reflected light radiated from the temperature measuring portion and reflected by the reflecting surface of the inner peripheral surface of the through hole with the radiation thermometer provided outside the housing, and measuring the temperature Department temperature It is obtained so as to measure.

  According to the circuit breaker having the thermal trip device of the present invention and the temperature inspection method thereof, a through-hole facing the temperature measuring portion of the bimetal or a member in contact with the bimetal is provided in the housing, and the inside of the through-hole Since the reflection surface for reflecting the measurement wavelength light of the radiation thermometer is formed on the peripheral surface, the radiation light including the reflected light radiated from the temperature measurement unit and reflected by the reflection surface of the inner peripheral surface of the through hole is emitted. Since the temperature of the temperature measuring unit can be measured by receiving light with a thermometer, the radiation thermometer can receive the radiated light from the temperature measuring unit, and the radiation thermometer directly wants the temperature measuring unit. Even if it is not possible, it is possible to receive the radiated light reflected by the reflecting surface on the inner peripheral surface of the through hole and measure the temperature of the temperature measuring unit.

BRIEF DESCRIPTION OF THE DRAWINGS It is a partial cross section front view which partially fractures | ruptures the circuit breaker which has the thermal tripping device in Embodiment 1 of this invention, and shows a temperature measurement aspect. It is a perspective view which shows the principal part of the circuit breaker which has the thermal tripping device in Embodiment 2 of this invention, and shows a temperature measurement aspect. It is a side view which shows the principal part of the circuit breaker which has the thermal tripping device in Embodiment 3 of this invention, and shows a temperature measurement aspect. It is a perspective view which shows the principal part of the circuit breaker which has the thermal tripping device in Embodiment 6 of this invention, and shows a temperature measurement aspect. It is a perspective view which shows the principal part of the circuit breaker which has a thermal tripping device, and demonstrates a temperature measurement aspect.

  First, the thinking technique before reaching the present invention will be described. FIG. 5 is a perspective view illustrating a temperature measurement mode as well as a main part of a circuit breaker having a thermal trip device. Reference numeral 21 denotes a bimetal used in the thermal tripping device. Reference numeral 22 denotes a heater through which the circuit current of the circuit breaker flows. The bimetal 21 is brought into contact with the yoke 23 along the bimetal 21 and an overcurrent flows as a circuit current. Heat and curve. The bimetal 21, the heater 22, and the yoke 23 are fixed in contact with each other. The integrated bimetal 21, heater 22 and yoke 23 are fixed to the bottom member of the casing 24.

  Here, an attempt is made to measure the temperature of the temperature measuring portion of the bimetal or a member in contact with the bimetal when the bimetal is heated by flowing a predetermined overcurrent. However, as described above, with the progress of miniaturization and higher density of circuit breakers, it has become difficult to install a radiation thermometer that measures the temperature of a bimetal or the like at a position where the bimetal is desired directly. Therefore, in the thinking technique of the present invention, the through-hole 25 facing the bimetal 21 or the temperature measuring portion 27 of the member in contact with the bimetal 21 is provided in the housing 24 in which the thermal tripping device is accommodated. In the case of FIG. 5, the through hole 25 is provided in the bottom member of the housing 24. Reference numeral 26 denotes a radiation thermometer provided outside the housing, and directly desires the temperature measuring unit 27 through the through hole 25. The radiation thermometer 26 can measure the temperature of the temperature measurement unit 27 by receiving the radiation emitted from the temperature measurement unit 27 and passing through the through hole 25.

  However, in order to sufficiently obtain the bimetal heating by the heater 22 and measure the temperature without deteriorating the shut-off performance, it is necessary to make the diameter of the through hole 25 equal to or less than a certain value. When the hole diameter of the through hole 25 is set to a certain value or less, the radiation temperature depends on the distance from the outlet 29 (outlet of the through hole 25 facing the radiation thermometer 26) on the outer surface of the housing of the through hole 25 to the temperature measuring unit 27. There is a possibility that the visual field of the total 26 is obstructed and an accurate temperature cannot be measured, and there is a problem that the type of circuit breaker to which the temperature measurement according to FIG. 5 can be applied is limited. In other words, there is a problem in that the radiated light 28 reaching the entire area of the light receiving lens 30 of the radiation thermometer 26 cannot be obtained from the through hole 25 and becomes a radiated light with a lacking peripheral portion. Since the distance between the light receiving lens 30 and the temperature measuring unit 27 is determined by the focal point of the light receiving lens 30 of the radiation thermometer 26, the radiation thermometer 26 is inserted into the through hole 25 in order to perform stable temperature measurement. It cannot be kept away from the exit 29.

Embodiment 1 FIG.
The present invention is intended to solve the problems of the conventional prior art and the above-described thinking technique. FIG. 1 is a partial cross-sectional front view showing a temperature measurement mode by partially breaking a circuit breaker having a thermal tripping device according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a yoke which is fixed in contact with the bimetal 2 so that a circuit current of the circuit breaker flows. 3 is a trip bar, 4 is a tripping mechanism, and 5 is a main circuit having a movable contact 5a and a fixed contact 5b. 6 is an adjustment mechanism for adjusting the trip time. The thermal tripping device includes a yoke 1, a bimetal 2, a trip bar 3, a tripping mechanism portion 5, and an adjustment mechanism 6.

The operation when an overcurrent exceeding the rated current flows is as follows.
(1) When an overcurrent flows through the yoke 1 or the bimetal 2, the temperature of the yoke 1 or the bimetal 2 rises.
(2) The bimetal 2 bends as the temperature of the bimetal 2 increases.
(3) The bending amount of the bimetal 2 increases, and the trip bar 3 is pushed.
(4) The tripping mechanism unit 4 is actuated to trip the movable contact 5a from the fixed contact 5b and instantaneously shut off (trip) the main circuit 5.

  The range from the start of overcurrent to the trip is defined by the standards such as JIS, and the product trip time must satisfy the range. However, the operating point of the tripping mechanism, that is, the position where the bimetal 2 pushes the trip bar 3 varies due to the accumulation of manufacturing variations such as processing / assembly errors of each component constituting the tripping device, variations in material characteristics, etc. Variation occurs in the time (trip time) from the start of energization to the trip. Therefore, in order to absorb such manufacturing variations, an adjustment mechanism 6 is provided at the tip of the bimetal 2 and the trip bar 3, and inspection and adjustment operations are performed in the assembly process.

In inspection / adjustment work, it is necessary to accurately measure the tripping characteristics of each workpiece. Usually, the trip characteristic is often measured by energizing a predetermined current value and measuring the trip time or measuring the amount of bimetal displacement during that time. However, since the trip time and bimetal displacement are greatly affected by the workpiece temperature and measurement environment temperature at the start of energization, measure the trip time or the measured environment based on the workpiece temperature and ambient temperature. It must be corrected.
On the other hand, the bending amount (displacement amount) of the bimetal is determined by the temperature and the bending coefficient. However, since the bending coefficient is known, the displacement amount can be obtained by measuring the bimetal temperature. Therefore, the trip characteristic can be measured by measuring the bimetal temperature.

In FIG. 1, reference numeral 7 denotes a housing for housing a thermal tripping device, movable contact 5a, fixed contact 5b and the like, and has an upper housing 7a and a lower housing 7b. The casing can be made of PET (polyethylene terephthalate) resin. Reference numeral 8 denotes a temperature measuring portion of the bimetal 2 or a member that contacts the bimetal 2 (in this case, the lower surface of the yoke 1). If the bimetal 2 and the yoke 1 and the heater are in contact with each other, the temperature of the yoke 1 and the heater and the temperature of the bimetal 2 are closely related, and the temperature of the member in contact with the bimetal 2 is measured. The temperature of the bimetal 2 can be calculated. Reference numeral 9 denotes a through hole (1 to 5Φ) facing the temperature measuring unit 8. In this case, the bottom member (1 to 10 mm) of the lower casing 7 b just below the bottom surface of the yoke 1 serving as the temperature measuring unit 8 is formed in a cylindrical shape. It has been drilled. Reference numeral 10 denotes a radiation thermometer incorporating an infrared absorption element, which is arranged at a position outside the housing where the distance from the temperature measuring unit 8 matches the focal length of the light receiving lens 10a. On the inner peripheral surface of the through hole 9, a reflection surface is formed that reflects the measurement wavelength light of the radiation thermometer 10.

  By forming the reflection surface on the inner peripheral surface of the through hole 9 in this way, the radiation thermometer 10 allows the infrared rays (that is, the radiated light 11) radiated from the temperature measuring unit 8 to pass directly through the through hole 9. In addition to the emitted light, the reflected light reflected by the reflecting surface of the inner peripheral surface of the through hole 9 can be observed. Therefore, sufficient radiated light can be observed compared to the case where direct radiated light from the temperature measuring unit 27 is observed as in the thinking technique of FIG. Further, even if the distance between the temperature measuring unit 8 and the outlet of the through hole 9 varies due to the bending of the bimetal, the radiated light from the temperature measuring unit 8 is stably incident on the radiation thermometer 10 and stable temperature measurement is possible. become.

A non-contact thermometer measures the temperature of an object by detecting the amount of infrared radiation radiated from the object. The amount of infrared radiation radiated from an object varies depending on the material and its surface state, and the amount of infrared energy (emissivity) radiated differs even at the same temperature. In a non-contact thermometer, the temperature is calculated based on an ideal black body (theoretical object with 100% emissivity), and other objects must be corrected according to the individual emissivity.
Since the emissivity is usually obtained experimentally, and it is difficult to obtain the emissivity of the measurement object in a short time, the emissivity cannot be obtained for each workpiece in the mass production process. Therefore, when the emissivity of the bimetal or its abutting member varies, the variation becomes a variation in temperature measurement. Furthermore, since the bimetal or its abutting member surface is generally a metallic luster surface, infrared rays radiated from other heat sources in the vicinity of the bimetal are easily reflected on the bimetal or its abutting member surface. If the reflected light enters the radiation thermometer, a measurement error occurs.

In addition, even if the emissivity is low, the temperature can be measured by correcting it according to the emissivity, but the absolute amount of infrared rays (radiated light) decreases, so the noise component in the measurement increases and the temperature is measured. Accuracy will be reduced. Therefore, it is desirable that the emissivity is high and constant for highly accurate temperature measurement.
Therefore, the emissivity can be increased and made constant by making the surface of the bimetal or its contact member the temperature measurement part black, preferably matte black. As a result, even at different temperature measuring parts, a constant high emissivity is obtained, so that the bimetal temperature or the temperature of the contact member can be stably measured with high accuracy. In addition, by using matte coating, reflection from other heat sources can be suppressed, and measurement errors can be reduced.

  To make it black, for example, there is a method by painting or etching. A matte black paint may be used to make the matte black. Moreover, you may make it matt black by oxidizing with etching. In this case, as the etching solution, for example, a sodium hydroxide solution or a phosphate solution is used when the bimetal is an iron-based material, and an acidic aqueous solution containing, for example, selenium is used when the bimetal is a copper-based material.

Embodiment 2. FIG.
FIG. 2 is a perspective view showing the temperature measurement mode as well as the main part of the circuit breaker having the thermal tripping device according to the second embodiment of the present invention. 1 denote the same or corresponding parts. A yoke 1 and a heater 16 are attached to the bimetal 2. The heater 16 has contacts fixed to the circuit current along a bimetal 2 with yaw click 1 stream. The integrated bimetal 2, the heater 16, and the yoke 1 are fixed to the bottom member of the lower casing 7b. The lower housing 7b is, for example, 100-500 mm wide × 50-300 mm long × 30-100 mm high. The temperature measuring unit 8 is the lower surface of the heater 16. A cylindrical through hole 9 is formed in the bottom member of the lower housing 7b so as to face the temperature measuring unit 8. The cylindrical through-hole 9 has a length of 1-10 mm and φ1-5 mm, for example. On the inner peripheral surface of the cylindrical through-hole 9, a reflection surface of an aluminum vapor deposition film that reflects the measurement wavelength 800 to 1800 nm of the radiation thermometer 10 is formed.

  In this way, the through-hole 9 is formed in the housing so as to face the temperature measuring portion 8 and a reflection surface is formed on the inner peripheral surface of the through-hole 9, so that about 1-20 mm from the outlet of the through-hole 9 at the time of temperature observation. By disposing the radiation thermometer apart, the radiation thermometer 10 allows the radiation light 11 radiated from the temperature measuring unit 8 to pass through the through hole 9 as well as the radiation light directly passing through the through hole 9. The radiant light reflected by the reflecting surface on the inner peripheral surface can also be observed, and sufficient radiated light can be observed. Further, even if the distance between the temperature measuring unit 8 and the outlet of the through hole 9 varies due to the bending of the bimetal, the radiated light from the temperature measuring unit 8 is stably incident on the radiation thermometer 10 and stable temperature measurement is possible. become.

Embodiment 3 FIG.
FIG. 3 is a side view showing the temperature measurement mode as well as the main part of the circuit breaker having the thermal tripping device according to the third embodiment of the present invention. 1 and 2 indicate the same or corresponding parts. The integrated bimetal 2, yoke 1 and heater 16 are fixed to the bottom member 7c of the lower casing. The temperature measuring unit 8 is the lower surface of the bimetal 2, and the lower surface is preferably black, preferably matte black. A cylindrical through hole 9 is formed in the bottom member 7c of the lower housing 7b so as to face the temperature measuring unit 8. A reflection surface of the radiation thermometer 10 is formed on the inner peripheral surface of the cylindrical through hole 9.

  As described above, the radiation thermometer is formed in the same manner as in the first and second embodiments by forming the through hole 9 in the casing so as to face the temperature measurement unit 8 and forming the reflection surface on the inner peripheral surface of the through hole 9. 10 observes not only the radiated light directly emitted from the temperature measurement unit 8 but also the radiated light reflected by the reflecting surface of the inner peripheral surface of the through hole 9. And sufficient radiation can be observed.

Embodiment 4 FIG.
In Embodiment 1, it is desirable that the reflection surface on which the measurement wavelength light of the radiation thermometer 10 formed in the through hole 9 is reflected has a reflectivity as high as possible. Therefore, for example, by forming a highly reflective substance such as a gold vapor deposition film or a dielectric multilayer film on the inner peripheral surface of the through-hole 9, the reflectivity becomes higher, and infrared rays absorbed by the inner peripheral surface are reduced. As a result of a lot of reflected light entering the radiation thermometer 10, more stable measurement is possible.

Embodiment 5 FIG.
In the first embodiment, the inner peripheral surface of the through-hole 9 is formed by forming a part of the material of the housing 7 including the through-hole 9 from aluminum which is a reflective material having a measurement wavelength of the radiation thermometer 10. Therefore, it is not necessary to form a reflection surface again, and the cost can be reduced.

Embodiment 6 FIG.
FIG. 4 is a perspective view showing the temperature measurement mode as well as the main part of the circuit breaker having the thermal tripping device according to the sixth embodiment of the present invention. 1, 2 and 3 indicate the same or corresponding parts. The integrated bimetal 2, yoke 1 and heater 16 are fixed to the bottom member of the lower housing 7b. The temperature measuring unit 8 is the lower surface of the bimetal 2, and the lower surface is preferably black, preferably matte black.

  A through-hole 17 is formed in the bottom member of the lower housing 7b so as to face the temperature measuring unit 8. The through-hole 17 has a substantially circular cross section, but is bent in the length direction. As a result, the temperature can be measured even in a place where the temperature measuring unit 8 is not directly visible from the installation position of the radiation thermometer 10. A reflection surface of the measurement wavelength light of the radiation thermometer 10 is formed on the inner peripheral surface of the through-hole 17. In addition, a part of the material of the housing 7b including the through hole 17 may be formed of a material that is a reflective material for the measurement wavelength light of the radiation thermometer 10.

  The radiated light radiated from the temperature measuring unit 8 is incident on the bent through hole 17 formed so as to face the temperature measuring unit 8, and the reflected light reflected by the reflecting surface is radiated from the bent through hole 17. Is received by the light receiving lens 10a. Therefore, it is possible to measure the temperature even where the temperature measuring unit 8 is not directly visible from the installation position of the radiation thermometer 10. Thus, the radiation thermometer 10 radiates from the temperature measurement unit 8 by forming the bent through hole 17 in the casing so as to face the temperature measurement unit 8 and forming the reflection surface on the inner peripheral surface of the bent through hole 17. The radiated light 11 reflected by the reflection surface on the inner peripheral surface of the bent through hole 17 can be observed, and the temperature of the temperature measuring unit 8 can be measured from the radiated light.

DESCRIPTION OF SYMBOLS 1 Yoke 2 Bimetal 3 Trip bar 4 Trip mechanism 5 Main circuit 5a Movable contact 5b Fixed contact 6 Adjustment mechanism 7 Housing 7a Upper housing 7b Lower housing 8 Temperature measuring section 9 Through-hole 10 Radiation thermometer 10a Light receiving lens 11 Sync light 16 Heater 17 Bent through hole

Claims (7)

A thermal trip device that performs a tripping operation between the movable contact and the fixed contact by bending of the heated bimetal is accommodated in the housing by overcurrent,
In a circuit breaker having a thermal tripping device in which the temperature of the temperature measuring part of a member abutting on the bimetal or the bimetal is measured with a radiation thermometer, and the operating time of the thermal tripping device is inspected,
A through hole facing the temperature measurement unit is provided in the housing,
A circuit breaker having a thermal trip device in which a reflection surface for reflecting the measurement wavelength light of the radiation thermometer is formed on an inner peripheral surface of the through hole.   The circuit breaker having a thermal trip device according to claim 1, wherein the through-hole provided in the casing so as to face the temperature measuring portion is bent in a longitudinal direction of the through-hole.   3. A circuit breaker having a thermal tripping device according to claim 1 or 2, wherein an aluminum vapor deposition film or a gold vapor deposition film that reflects the measurement wavelength light of the radiation thermometer is formed on an inner peripheral surface of the through hole. vessel.   The circuit breaker having a thermal trip device according to claim 1 or 2, wherein a dielectric multilayer film that reflects the measurement wavelength light of the radiation thermometer is formed on an inner peripheral surface of the through hole.   The circuit breaker having a thermal trip device according to claim 1 or 2, wherein the housing material of the portion where the through hole is provided is formed of a reflection material for the measurement wavelength light of the radiation thermometer.   The circuit breaker having the thermal tripping device according to any one of claims 1 to 5, wherein a surface of the temperature measuring unit is black or matte black. A thermal trip device that performs a tripping operation between the movable contact and the fixed contact by bending of the heated bimetal is accommodated in the housing by overcurrent,
Circuit breaker temperature inspection method having a thermal trip device in which the temperature of a temperature measuring section of a bimetal or a member in contact with the bimetal is measured with a radiation thermometer, and the operating time of the thermal trip device is inspected In
A through hole facing the temperature measurement unit is provided in the housing,
On the inner peripheral surface of the through hole, a reflection surface that reflects the measurement wavelength light of the radiation thermometer is formed,
Measures the temperature of the temperature measurement unit by receiving the radiated light including the reflected light radiated from the temperature measurement unit and reflected by the reflection surface of the inner peripheral surface of the through hole with the radiation thermometer provided outside the housing. A method for inspecting a temperature of a circuit breaker having a thermal trip device.

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