CN107221480B - Trip device with long trip time - Google Patents
Trip device with long trip time Download PDFInfo
- Publication number
- CN107221480B CN107221480B CN201610165251.4A CN201610165251A CN107221480B CN 107221480 B CN107221480 B CN 107221480B CN 201610165251 A CN201610165251 A CN 201610165251A CN 107221480 B CN107221480 B CN 107221480B
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- Prior art keywords
- bimetal
- bimetallic strip
- bimetallic
- temperature
- sheet
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
- H01H71/10—Operating or release mechanisms
- H01H71/12—Automatic release mechanisms with or without manual release
- H01H71/14—Electrothermal mechanisms
- H01H71/16—Electrothermal mechanisms with bimetal element
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
- H01H71/10—Operating or release mechanisms
- H01H71/12—Automatic release mechanisms with or without manual release
- H01H71/14—Electrothermal mechanisms
- H01H71/16—Electrothermal mechanisms with bimetal element
- H01H71/164—Heating elements
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- Thermally Actuated Switches (AREA)
Abstract
A trip device, comprising: a first bimetallic sheet and a second bimetallic sheet, wherein said first bimetallic sheet and said second bimetallic sheet are connected together at one of their ends and are spaced apart from each other at their other end; normally the two bimetal strips are close together and when the second bimetal strip is heated it heats the first bimetal strip.
Description
Technical Field
The present disclosure relates to a trip device, and more particularly, to a trip device having a long trip time. The tripping device is particularly applied to the application that the starting current (6-8 Ir) of a large fan, a wind turbine and the like has long duration and needs long tripping time protection.
Background
In the starting process of the motor, the motor needs to bear the starting current (6-8 Ir) of the motor for a long time, sometimes exceeding 1min or even longer, for example, large-scale wind turbines and other applications. However, the tripping time is short by means of direct heating and indirect heating in the prior art, and longer tripping protection is difficult to realize. In addition, the cost of the indirect heating method is very high.
Disclosure of Invention
To overcome the drawbacks of the prior art, the present disclosure provides a trip device, which includes: a first bimetallic strip and a second bimetallic strip, wherein said first bimetallic strip and said second bimetallic strip are connected together at one of their ends and are spaced apart from each other at their other end; normally, the two bimetallic strips are close to each other. When the second bimetallic sheet is heated, it is capable of heating the first bimetallic sheet.
The second bimetallic strip can be heated directly by an electric current or indirectly by a heating device.
The direct heating means that the current passes directly through the second bimetallic strip, which is directly heated due to the thermal effect of electricity.
The indirect heating means that current passes through a heating device, an insulating material is arranged between the heating device and the second bimetallic strip for isolation, and heat generated by the heating device passes through the insulating material and then reheats the second bimetallic strip.
The connection of the first and second bimetallic sheets at one of their ends is achieved by welding or by fasteners; the two may or may not be electrically conductive (separated by a thermally conductive and electrically non-conductive material, such as mica).
The heating of the first bimetallic sheet by the second bimetallic sheet is performed by: 1) heat conduction through the ends where they are joined together; 2) thermal convection through the air gap between the bi-metallic strips and thermal radiation.
According to one aspect, in a steady state, the current passing through the second bimetallic strip causes a temperature rise in the second bimetallic strip, which also occurs on the first bimetallic strip due to the action of conductive convective radiation, similar to the temperature rise of the second bimetallic strip. After the final temperature has stabilized, the two bimetal strips reach a similar/identical temperature, causing the first bimetal strip to always follow the deformation of the second bimetal strip and keep a gap. In a transient state, the second bimetal generates a rapid temperature rise due to the current passing through the second bimetal, the second bimetal generates a rapid deformation, the first bimetal and the second bimetal generate a V-shaped gap between the first bimetal and the second bimetal, convection and radiation between the two bimetal are blocked, and then the temperature rise of the first bimetal is slower than that of the second bimetal and the deformation speed of the first bimetal is slower than that of the second bimetal.
According to another aspect, in a steady state, the current passing through the heating means causes a temperature increase in the second bimetallic strip, which after a certain time also causes a similar temperature increase in the first bimetallic strip, and finally the two bimetallic strips reach the same temperature after the temperature has stabilized, causing the first bimetallic strip to always follow the deformation of the second bimetallic strip and remain gapped. In a transient state, the second bimetal generates a rapid temperature rise due to the current passing through the heating device, the second bimetal generates a rapid deformation, the first bimetal and the second bimetal generate a V-shaped gap between the first bimetal and the second bimetal, the convection and radiation heating effect of the first bimetal from the second bimetal is blocked, and the temperature rise of the first bimetal is slower than that of the second bimetal and the deformation speed of the first bimetal is slower than that of the second bimetal.
The trip device based on the present disclosure includes two bimetal strips, wherein the temperature rising speed of the first bimetal strip is far slower than that of the second bimetal strip. In practical cases, the gap between the first bimetal and the second bimetal will increase due to the difference of their temperature rises, and the thermal impedance between the first bimetal and the second bimetal will also increase, so that the temperature rise of the first bimetal linked with the trip mechanism will be slower, and the deformation speed will be slower, thereby realizing a long trip time.
In addition, the heating method according to the present disclosure is not expensive. The tripping device based on the disclosure is particularly applied to large fans and the like with long starting current (6-8 Ir) duration and needing long tripping time protection.
So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. There are, of course, embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto.
Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components and the equivalents of steps set forth in the following description or illustrated in the following drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of the present invention. It is important, therefore, that the appended claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Drawings
The present invention will be better understood and its advantages will become more apparent to those skilled in the art from the following drawings. The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations and are not intended to limit the scope of the present disclosure.
Fig. 1(a) and 1(b) show a combination of a bimetal and a heating device in the prior art;
fig. 2(a) and 2(b) illustrate the combination of two bi-metallic strips and a heating device according to the present disclosure;
fig. 3 illustrates a V-shaped gap between two bi-metallic strips according to the present disclosure.
Detailed Description
Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. The features and advantages of the present invention will be appreciated by those skilled in the art from the accompanying drawings and the corresponding written description.
Fig. 1(a) and 1(b) show a combination of a bimetal and a heating device in the prior art.
In fig. 1(a), a current (as indicated by an arrow in the figure) directly passes through the bimetal 2, and the bimetal 2 is heated to deform, thereby triggering tripping of the tripping mechanism. Generally, based on the configuration in fig. 1(a), the bimetal 2 will heat/deform rapidly under the action of the thermal effect of the current, so that only a short trip protection time can be provided.
In fig. 1(b), the heating device 1 and the bimetal 2 have an insulating and heat-conducting material therebetween, and when a current (as indicated by an arrow in the figure) passes through the heating device 1, the bimetal 2 is heated to deform, thereby triggering the tripping of the tripping mechanism, but due to the presence of the insulating and heat-conducting material, the bimetal 2 in fig. 1(b) deforms at a slower speed compared with the configuration in fig. 1(a), thereby providing a slightly longer tripping protection time.
However, the above-mentioned direct heating and indirect heating methods in the prior art have difficulty in achieving longer trip time. In particular, the method cannot be used for the application that the starting current of a large fan, a wind turbine and the like has long duration and needs long trip time protection.
In order to overcome the disadvantages of the prior art, a combination of two bimetal strips according to the present disclosure and one heating device is provided as shown in fig. 2(a) and 2 (b).
According to a first embodiment of the present disclosure, there is provided a trip device as shown in fig. 2(a), including: a first bimetal sheet 3 and a second bimetal sheet 4, wherein said first bimetal sheet 3 and said second bimetal sheet 4 are connected together at one of their ends and are separated from each other at their other end; when an electric current is passed through the second bimetallic strip 4, it is capable of heating the first bimetallic strip 3. The first bimetallic strip 3 deforms, so that the tripping mechanism of the tripping device is driven to trip.
The second bimetallic strip 4 can be heated directly by the electric current.
The current passes through the second bimetallic strip 4 directly, and heats the second bimetallic strip 4 under the action of the thermal effect of the current.
The connection of the first bimetallic strip 3 and the second bimetallic strip 4 at one of their ends is effected by welding or by fasteners.
In a steady state, the current through the second bimetallic strip 4 causes a temperature increase of the second bimetallic strip 4, and after a certain time a similar temperature increase of the second bimetallic strip 4 also occurs on the first bimetallic strip 3. After the final temperature has stabilized, the two bimetal strips reach a similar/identical temperature, causing the first bimetal strip 3 to always follow the deformation of the second bimetal strip 4 and remain gapped.
In a transient state, due to the current passing through the second bimetallic sheet 4, the second bimetallic sheet 4 generates a rapid temperature rise, the second bimetallic sheet 4 generates a rapid deformation, the first bimetallic sheet 3 and the second bimetallic sheet 4 generate a V-shaped gap (as shown in fig. 3) between them, the convection and radiation heating effect of the second bimetallic sheet 4 on the first bimetallic sheet 3 is hindered, and thus the temperature rise of the first bimetallic sheet 3 is slower than that of the second bimetallic sheet 4 and the deformation speed of the first bimetallic sheet 3 is slower than that of the second bimetallic sheet 4.
The heating of the first bimetallic strip 3 by the second bimetallic strip 4 is achieved by means of heat conduction, convection and radiation.
Compared to the prior art, the embodiment shown in fig. 2(a) achieves a slower deformation speed of the first bimetal by using an additional bimetal, i.e., the second bimetal, thereby providing a relatively longer trip protection time.
According to a second embodiment of the present disclosure, there is provided a trip device as shown in fig. 2(b), including: a first bimetal sheet 3 and a second bimetal sheet 4, wherein said first bimetal sheet 3 and said second bimetal sheet 4 are connected together at one of their ends and are separated from each other at their other end; when an electric current is passed through the heating device 1, the heating device 1 generates heat and heats the second bimetal sheet 4 by thermal conduction and then heats the first bimetal sheet 3. The first bimetallic strip 3 deforms, so that the tripping mechanism of the tripping device is driven to trip.
The second bimetallic strip can be indirectly heated by the heating device 1.
Between the heating device 1 and the second bimetallic strip 4 there is an insulating and heat conducting material, the heating device heating the second bimetallic strip 4 mainly in a conductive manner.
The connection of the first bimetallic strip 3 and the second bimetallic strip 4 at one of their ends is effected by welding or by fasteners.
In a steady state, the current passing through the heating device 1 causes a temperature increase in the second bimetallic strip 4, and after a certain time a similar temperature increase in the first bimetallic strip 3 also occurs as in the second bimetallic strip 4. After the final temperature has stabilized, the two bimetal strips reach a similar/identical temperature, causing the first bimetal strip 3 to always follow the deformation of the second bimetal strip 4 and remain gapped.
In a transient state, due to the rapid temperature rise of the second bimetallic sheet 4 caused by the current passing through the heating device 1, the second bimetallic sheet 4 is rapidly deformed, the first bimetallic sheet 3 and the second bimetallic sheet 4 generate a V-shaped gap therebetween, which hinders the convection and radiation heating effect of the first bimetallic sheet 3 from the second bimetallic sheet 4, thereby causing the temperature rise of the first bimetallic sheet 3 to be slower than that of the second bimetallic sheet 4 and the deformation speed of the first bimetallic sheet 3 to be slower than that of the second bimetallic sheet 4.
The heating of the first bimetallic strip 3 by the second bimetallic strip 4 is achieved by means of heat conduction, convection and radiation.
In the embodiment shown in fig. 2(b), since no current flows through the second bimetal 4 and there is an insulating and heat conducting material between the second bimetal and the heating device 1, the deformation speed of the first bimetal shown in fig. 2(b) is much slower than that of the first bimetal shown in fig. 2(a), which can provide a longer trip protection time than the embodiment shown in fig. 2 (a).
The trip device based on the present disclosure includes two bimetal strips, wherein the temperature rising speed of the first bimetal strip is far slower than that of the second bimetal strip. In practical situations, in an instant state, the gap between the first bimetal and the second bimetal will increase due to the difference of the temperature rise of the first bimetal and the second bimetal, and the thermal impedance between the first bimetal and the second bimetal will also increase, so that the temperature rise of the first bimetal linked with the tripping mechanism will be slower, the deformation speed will be slower, and a long tripping time can be realized.
In addition, the heating method according to the present disclosure is not expensive. The tripping device based on the disclosure is also particularly applied to the application of large fans, wind turbines and the like with long starting current (6-8 Ir) duration and long tripping time protection.
While the invention has been described in the specification and drawings with reference to specific embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for method steps and test devices described herein without departing from the scope of the invention as defined in the claims. Furthermore, the combination and arrangement of features, elements and/or functions between specific embodiments herein is clearly apparent and, thus, in light of this disclosure, one skilled in the art will appreciate that features, elements and/or functions of an embodiment and method steps may be incorporated into another specific embodiment as appropriate, unless described otherwise, above. In addition, many modifications may be made to adapt a particular situation to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the foregoing description and the appended claims.
Claims (8)
1. A trip device, comprising: a first bimetal sheet and a second bimetal sheet facing each other and capable of forming a V-shaped gap therebetween; wherein the first bimetallic sheet and the second bimetallic sheet are connected together at one of their ends and are separated from each other at their other end; normally the two bimetallic strips are close together and when the second bimetallic strip is heated it heats the first bimetallic strip, the V-shaped gap impedes the convective and radiative heating of the first bimetallic strip from the second bimetallic strip.
2. The trip unit of claim 1, wherein said second bimetallic strip is capable of being heated directly by an electric current or indirectly by a heating device;
the direct heating means that current directly passes through the second bimetallic strip, and the second bimetallic strip is directly heated due to the thermal effect of electricity;
the indirect heating means that current passes through a heating device, an insulating material is arranged between the heating device and the second bimetallic strip for isolation, and heat generated by the heating device passes through the insulating material and then reheats the second bimetallic strip.
3. The trip unit of claim 1, wherein the connection of the first bimetallic strip and the second bimetallic strip at one of their ends is by welding or by a fastener.
4. The trip unit of claim 1, wherein the heating of the first bimetallic strip by the second bimetallic strip is performed by: 1) heat conduction through the ends where they are joined together; 2) thermal convection through the air gap between them and thermal radiation.
5. The trip unit according to claim 1, wherein in a steady state, the current passing through the second bimetal causes the second bimetal to rise in temperature, and the first bimetal also rises in temperature due to the action of the conductive convection radiation, and after the temperature is finally stabilized, the two bimetal reaches the same temperature, so that the first bimetal always follows the deformation of the second bimetal and keeps a gap.
6. The trip unit according to claim 1, wherein in the transient state, the second bimetal generates a rapid temperature rise due to the current passing through the second bimetal, the second bimetal generates a rapid deformation, the first bimetal and the second bimetal generate a V-shaped gap therebetween, the convection and the radiation between the two bimetal are blocked, and the temperature rise of the first bimetal is slower than that of the second bimetal and the deformation speed of the first bimetal is slower than that of the second bimetal.
7. The trip unit according to claim 1, wherein in a steady state, the current passing through the heating device causes the second bimetal to rise in temperature, and after a period of time, the first bimetal also rises in temperature, and finally the two bimetal pieces reach the same temperature after the temperature is stabilized, so that the first bimetal piece always follows the deformation of the second bimetal piece and keeps a gap.
8. The trip unit of claim 1, wherein in a transient state, current passing through a heating device causes a rapid temperature rise in said second bimetallic strip, said second bimetallic strip rapidly deforms, causing a slower temperature rise in said first bimetallic strip than in said second bimetallic strip and a slower rate of deformation in said first bimetallic strip than in said second bimetallic strip due to said V-shaped gap impeding convective and radiative heating of said first bimetallic strip from said second bimetallic strip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610165251.4A CN107221480B (en) | 2016-03-22 | 2016-03-22 | Trip device with long trip time |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610165251.4A CN107221480B (en) | 2016-03-22 | 2016-03-22 | Trip device with long trip time |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107221480A CN107221480A (en) | 2017-09-29 |
| CN107221480B true CN107221480B (en) | 2020-06-26 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610165251.4A Active CN107221480B (en) | 2016-03-22 | 2016-03-22 | Trip device with long trip time |
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| Country | Link |
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| CN (1) | CN107221480B (en) |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE441507A (en) * | 1940-05-22 | 1941-06-30 | ||
| JPH0817324A (en) * | 1994-07-04 | 1996-01-19 | Mitsubishi Electric Corp | Bimetal device and its manufacture |
| JP2001176371A (en) * | 1999-12-17 | 2001-06-29 | Fuji Electric Co Ltd | Thermomotive overload detection device |
| KR101529591B1 (en) * | 2013-12-19 | 2015-06-17 | 엘에스산전 주식회사 | Trip device for curcuit breaker |
| JP6272155B2 (en) * | 2014-06-11 | 2018-01-31 | 三菱電機株式会社 | Thermal trip device for circuit breaker |
| CN205621685U (en) * | 2016-03-22 | 2016-10-05 | 施耐德电器工业公司 | Trip gear with long dropout time |
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2016
- 2016-03-22 CN CN201610165251.4A patent/CN107221480B/en active Active
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| Publication number | Publication date |
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| CN107221480A (en) | 2017-09-29 |
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