Claims:1. A switchgear device (1) comprising:
an arc shield (12) mounted on top;
a venting arrangement comprises:
plurality of vents (4a, 4b, 4c, 5a, 5b, 5c, 6a, 7a and 7b) provided on terminal supports (4, 5), on a top crosspiece (6) and on a bottom crosspiece (7), respectively;
wherein said vents (4c) and (5c) provides an opening area for cold air to move in and flow over top of said terminal supports, and said vents (4a), (4b), (5a), (5b) (6a) acts as a passage for a hot air to move out thus improving air flow circulation and hence convection and reducing temperature at plurality of termination adaptors (9); and said vents (7a) and (7b) adapted for said cold air to move in from bottom side of device so as to increase cold air intake.

2. The device as claimed in claim 1, wherein said top crosspiece (6) and said bottom crosspiece (7) are mounted above and below said terminal supports (4) and (5) respectively.

3. The device as claimed in claim 1, wherein said cold air moves inwards from said bottom piece through said vents (7a), (7b) and moves upwards and finally exit from said top crosspiece through said vents (6a).
, Description:TECHNICAL FIELD

[001] The present subject matter described herein, in general, relates to a switching devices such as a circuit breakers, and more particularly the invention relates to a venting arrangement in air circuit breaker assembly for improved convection and cooling of the terminals.

BACKGROUND

[002] Circuit breaker are commonly known as interrupters that opens and closes the contacts to stop and start the flow of electrical current to the circuit. Circuit breakers are used to safeguard the electrical equipment from over current situations or short circuit current situations in equipment. In case of fault current conditions, the electrical contacts within the circuit breaker will open and stops the flow of current through the circuit breaker to the equipment. In case of fault generation, circuit breakers are expected to withstand fault current before opening the contacts.

[003] Recent advances and optimization of design has resulted in reduction of switchgear dimensions for the same performance. Accordingly, the heat generation per unit volume has increased, causing the thermal behavior of a device to become a main issue in development. But CAE simulation has made it simpler and fast process to analyze thermal behavior of the product. One main aim of the application of simulation methods in switchgear design is to cut the costs for experimental investigations and to shorten the development cycles. All switchgear needs to fulfil certain standards for their electrical, mechanical and thermal behavior. A circuit breaker contains several heat sources that causes its temperature rise, like Joule heat losses in current carrying parts, thermal bimetal, contact resistances and so on. Heat generated is dissipated by means of various modes of heat transfer- conduction, convection and radiation. Convection plays major role in heat dissipation of the components and lowering the temperature of the breaker.

[004] Reference is made to US2293452 which relates to magnetic blowout type air circuit breakers. Temperature rise is reduced with the help of Curved fins provided on outer side of arc chutes for improved compact gas deflecting and dissipating means for rendering harmless the arc and switching gases blown from the arc chutes.

[005] Reference is further made to US2824939 which talks about improving exit of hot gases from circuit breakers using forced convection. Motor driven fan is used to exhaust air or other cooling fluids from the compartment. A tube is used to vent out the hot gases thereby reducing the temperature of the contact assembly.

[006] Reference is still made to US2942086 which talks about means for reducing amount of ionized gas discharge above the arc chute of an air. A chimney vent is provided above the arc runners at the exhaust of arc chutes for improved interruption.

[007] Reference is further made to US2942086 which talks about improving convection by assembly of a vented mounting block to vent out gases from the circuit breaker by channeling through the opening of the breaker through internal passageway of the mounting block.

[008] Thus, in view of the existing venting system, there exists a dire need for a modified venting system with terminal supports for modern switchgear devices for improved convection and hence thermal performance.

SUMMARY OF THE INVENTION

[009] The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.
[0010] An objective of the present invention is to provide an improved venting arrangement optimized with the help of Finite-Element-Method (FEM) or Computational Fluid Dynamics (CFD) simulation process to improve convection near the heat generating parts which helps in reduction of temperature.

[0011] Another objective of the present invention is to provide vents on terminal supports and top and bottom crosspiece for increasing the air flow and thus enhancing thermal performance of the breaker.

[0012] Accordingly to one aspect, the present invention provides a switchgear device comprising: an arc shield mounted on top; a venting arrangement comprises: plurality of vents provided on terminal supports on a top crosspiece and on a bottom crosspiece respectively; wherein said vents provides an opening area for cold air to move in and flow over top of said terminal supports, and said vents on said terminal supports acts as a passage for a hot air to move out thus improving air flow circulation and hence convection and reducing temperature at plurality of termination adaptors; and said vents on the bottom cross piece adapted for said cold air to move in from bottom side of device so as to increase cold air intake.

[0013] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

[0014] Figure 1 illustrates the overview of draw-out switchgear device, according to one implementation of the present invention.

[0015] Figure 2 shows the switchgear device with vents for improved convection, according to one implementation of the present invention.

[0016] Figure 3 illustrates a left and right terminal support with vents, according to one implementation of the present invention.

[0017] Figure 4 illustrates a top and bottom crosspiece with vents for improved convection, according to one implementation of the present invention.

[0018] Figure 5 illustrates an air flow velocity vector diagram with improved convection due to vents, according to one implementation of the present invention.

[0019] Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0020] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

[0021] Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

[0022] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

[0023] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0024] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0025] Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

[0026] It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0027] It is also to be understood that the term “module” is used in the specification to indicate an apparatus, unit, component and the like. The term “means” when used in the specification is taken to specify the mode by which desired result is achieved.

[0028] The present invention can be implemented with an electrical switching system that may include but not limited to, circuit breakers or thermo-magnetic breaker, molded case circuit breaker (MCCB) residual circuit breaker (RCB), earth leakage circuit breaker (ELCB) and the like.

[0029] In one implementation, the present invention discloses simulation methodology with combined FEM and CFD analysis procedure to modify venting near the terminals of air circuit breaker and hence improve the air flow path near heat generating parts. Improved air flow path improves convection coefficient, hence better heat dissipation at terminals and reduced temperature.

[0030] In the implementation, FEM analysis is performed to estimate mV drop of the breaker and heat generation in each component of current carrying path. These outputs from FEM analysis are used as an inputs to CFD analysis. CFD simulation of entire breaker assembly is performed for flow analysis and to estimate temperature profile of breaker. Based on the fluid flow pattern obtained for existing design of breaker, design of terminal supports and other components were modified with improved venting system to get better air flow circulation at the breaker terminal. CFD simulations performed with modified design to get optimized venting arrangement for the application. This invention of modified design has improved convection coefficient up to 20% and significantly reduced temperature at terminals.

[0031] The components of the present invention as shown in the figures 1-5 are listed below:
1. Switchgear Device
2. Cradle Assembly
3. Breaker
4. Right Support
Vents 4a, 4b and 4c.
5. Left Support
Vents 5a, 5b and 5c.
6. Top Crosspiece
Vents 6a
7. Bottom Crosspiece
Vents 7a and 7b.
8. Sideplate
9. Termination Adaptor
10. Top Terminal
11. Bottom Terminal
12. Arc Shield

[0032] In one implementation, reference is made to figure (1) which shows an overview of a Draw-out Switchgear device (1) comprising of a cradle (2) and operating breaker (3).
[0033] In one implementation, reference is made to figure (2) which shows rear view of a switchgear device (1) with arc shield (12) mounted on top. Termination adaptors (9) are also shown. The Figure Shows Rear view with vents for improved convection provided on breaker terminal supports right (4) and left (5). Vents (4a), (4b), and (4c) are provided on right terminal support (4) and vents (5a), (5b) and (5c) are provided on left terminal support (5). Vents (4c) and (5c) provides opening area for cold air to move in and flow over top terminals which helps in increased convection coefficient there and effectively helps in reducing temperature. Opening (7a) and (7b) are provided on bottom crosspiece (7) for cold air to move in from bottom side of device and increases cold air intake which helps in improved heat dissipation and maintaining temperature under specified level fulfilling standard requirements. Vents (4a), (4b), (5a), (5b) and vents (6a) provided on top crosspiece (6) are used as a passage for hot air to move out thus improving air flow circulation and hence convection and reducing temperature at the termination adaptors (9).

[0034] In one implementation, reference is made to figure (3) which shows right terminal support (4) and left terminal support (5) with vents for improving heat dissipation.

[0035] In one implementation, reference is made to figure (4) which shows top crosspiece (6) with vents (6a) and bottom crosspiece (7) with vents (7a), (7b). Cold air moves inwards from vents (7a), (7b) and moves upwards and finally exit from vents (6a). Top crosspiece (6) and bottom crosspiece (7) are mounted above and below the terminal supports (4) and (5) respectively.

[0036] In one implementation, reference is made to figure (5) which shows air flow path for the design and improved venting arrangement. It clearly shows increased air circulation from bottom to top as area available for entry is more than previous design. Cold air moves in from vents provided at middle of terminal supports and bottom crosspiece and moves out from vents on upper side of terminal supports and top crosspiece. This arrangement helps in improved convective heat dissipation and thus enhancing the thermal performance of the switchgear device.

[0037] Some of the non-limiting advantaged of the present invention, are mentioned below:
• More efficient and improved convection in switchgear device.
• Better air flow path and increased flow circulation with new venting design.
• Enhanced thermal performance.
• Enhanced breaker life.

[0038] Although a switchgear device with improved venting arrangement for effective convection have been described in language specific to structural features and/or methods, it is to be understood that the embodiments disclosed in the above section are not necessarily limited to the specific features or methods or devices described. Rather, the specific features are disclosed as examples of implementations of the switchgear device with improved venting arrangement for effective convection.