FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION (See section 10 and rule 13)
TITLE OF THE INVENTION A vacuum contactor assembly
APPLICANT
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030. Maharashtra. India, an Indian Company
INVENTORS
Mahesh Kashinath Sathe of Crompton Greaves Ltd, Industrial Design Centre, Global R&D
Centre, Kanjurmarg (East), Mumbai 400042, Maharashtra, G.Nandeesh of Crompton Greaves Lid, Power Apparatus and Systems Lab, Global R&D Centre, Kanjurmarg (East). Mumbai 400042, Maharashtra, Arunachalam and Deosharan Roy of Crompton Greaves Ltd, Analytics Centre, Global R&D Centre, Kanjurmarg (East), Maharashtra, and Kiran Chavan of Crompton Greaves Ltd, S6 & Power Quality Division, D2, MIDC, Waluj, Aurangabad. 431136. Maharashtra, India, all Indian Nationals
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
[0001] The present invention relates generally to vacuum contactors and more
particularly, to an assembly of vacuum contactors.
DESCRIPTION OF THE BACKGROUND ART
[0002] Switching devices such as vacuum contactors typically include three vacuum
capsules having a corresponding fixed and moving contacts disposed within a vacuum housing therein. A spring loaded drive insulator drives the moving contact within the vacuum housing, Further, a horizontal lever is used for synchronizing movement of the three moving contacts with the spring loaded guided rods (two numbers). The guide rods are connected to the moving magnet of a solenoid sub assembly for driving horizontal lever when the solenoid is operated in ON & OFF conditions. The fixed and moving copper terminals connected to fixed contact and moving contact of the vacuum housing wherein the moving terminal carries braided copper portion for required flexibility during movement of moving contact.
[0003] The horizontal lever design with all available products is of hinged-type
design placed horizontally with solenoid movement. Horizontal mounting makes vacuum contactor assembly components difficult to access and service. If problem persists for a longer duration, maintaining positive contact between the fixed and the movable contacts becomes difficult and most unlikely situation they may break contact.
[0004] Some manufacturers have claimed mounting of vacuum contactor in inclined.
vertical downward and horizontal fashion but have not considered vacuum capsule moving contact bellow based flexibilities existence based contact continuity problems that might be evident with possible mounting claimed which ultimately demand some adjustment of vacuum

contactor assembly components. Further since the hinged movement of horizontal lever does create some lateral forces which act on drive insulator and thereby on the moving contact flexible below there is need to avoid such lateral forces generation for vacuum capsule safety.
[0005] Similarly the solenoid design is also normally a double coil design
horizontally mounted with moving magnet connected to hinged horizontal lever making i! difficult for adjustments needed with moving magnet and measurement of gap between moving magnet and fixed magnet of solenoid for humming noise reduction after vacuum contactor assembly is made ready which states a necessity of some automatically adjusting mechanism for moving magnet perfect closure (without any air gap) with fixed magnet which ultimately shall reduce the humming noise.
[0006] Therefore, there is a need in the art to have flexibility of assembling of
vacuum contactor, life of components to reduce the noise with ease of maintenance and service of vacuum contactor.
SUMMARY OF THE INVENTION
[0007] An object of the present invention is to provide a vacuum contactor assembly
that allows a movable contact to linearly move against a fixed contact so as to make and break electrical connection with the fixed contact.
[0008] Another object of the present invention is to provide a vacuum contactor
assembly that reduces rupture within a bellow disposed around a movable contact within a vacuum capsule thereby improving the life of vacuum contactor.
[0009] Accordingly disclosed herein is a vacuum contactor assembly including a
housing, at least one vacuum casing disposed within the housing and including a fixed contact

and a movable contact separable from each other in spaced apart relationship, a portion of the movable contact protruding outwardly from the vacuum casing, an actuating means disposed within the housing for allowing the movable contact to open and close against the fixed contact, the actuating means including, an electromagnet for selectively generating magnetic flux in its proximal areas, and a moving magnet positioned adjacent to the electromagnet in spaced apart relationship and vertically displaceable between a biased position and a released position under the influence of the magnetic flux, the movable contact being electrically coupled to the fixed contact in the biased position and being electrically separated from the fixed contact in the released position, and a mechanical linkage coplanarly arranged with the fixed and the movable contacts and including a pair of parallely arranged horizontal rods, a first horizontal rod fixedly connected to the moving magnet and displaceable between the biased and released positions whereas, the second horizontal rod is connected to the movable contact via an insulator, opposite ends of the first and the second horizontal rods being connected by a pair of parallely arranged vertical rods, wherein the pair of vertical rods linearly transfer displacement of the first horizontal rod to the movable contact via the second horizontal rod.
[0010] According to some embodiments, the first horizontal rod has at least one first
guiding bush attached thereto, the guiding bush slidably connected with a guide pin fixedly attached to a bottom portion of the housing for allowing the first horizontal rod to move between the biased and released positions.
[0011 ] According to some embodiments, the housing has an intermediate plate
dividing the housing into an upper section and a bottom section, the upper section having the vacuum casing and the second horizontal rod disposed therein whereas, the bottom section having the actuating means and the first horizontal rod disposed therein, respectively.

[0012] According to some embodiments, the intermediate plate has a pair of holes
formed thereon, each of the pair of holes having a second guiding bush positioned therein so as to allow a corresponding vertical rod to movably pass through.
[0013] According to some embodiments, the insulator has a front end, a back end and
a longitudinal portion extending from the back end, the top end fixedly connected to the movable contact whereas the longitudinal portion is slidably received within the opening, end of the longitudinal portion received outside the opening is locked against the second horizontal rod by a locking nut.
[0014] It is to be understood that both the foregoing general description and the
following detailed description of the present embodiments of the invention are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention and together with the description serve to explain the principles and operation of the invention.
A BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The above-mentioned and other features and advantages of the various
embodiments of the invention, and the manner of attaining them, will become more apparent and will be better understood by reference to the accompanying drawings, wherein:
[0016] FIG. 1 is a front side perspective view of a vacuum contactor assembly
according to an embodiment of the present invention;

[0017] FIG. 2 is a back side perspective view of the vacuum contactor assembly of
FIG. l;and
[003 8] FIG. 3 is a front cross-sectional view of the vacuum contactor of FIGS. 1 and
2 illustrating assembly of the internal components.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] FIG. i broadly illustrates the constructional features of a vacuum contactor
assembly 100 according to an embodiment of the present invention. The vacuum contactor assembly 100 includes a housing 102 (partially shown) that secures various mechanical and electrical components forming the vacuum contactor assembly 100 therein. The housing 102. as shown in FIG. 1, has open structure defined by a top end 104, a bottom end 106, a front side (not shown), a back side 108 (See FIG. 2), and a pair of two opposite sides 1 10 orthogonally arranged with each other to define the housing 102. Further, the housing 102 has an intermediate plate 112 positioned generally in the middle of the housing 102 so as to divide the housing 102 into an upper section 114 and a lower section 116. The upper section 114 has securely disposed therein at least one vacuum capsule 118 that has a fixed contact 120 and a movable contact 122 (See FIG. 3) separable against each other in vacuum. The lower section I 16 has an actuating means 124 disposed therein and a mechanical linkage 126 that acts as a linkage between the actuating means 124 and the movable contact 122 of the vacuum capsule 118. Further, a portion of the mechanical linkage 126 is occupied within the upper section 114 and rest of the portion of the mechanical linkage 126 is positioned within the lower section 116. Furthermore, the mechanical linkage 126 transfers energy obtained from the actuation means to the movable contact 122.
[0020] Preferably, as seen in FIG..3, the vacuum capsule 118 is coated with PU
(polyurethane) potting 128 for increasing the creepage distance. Further, the fixed contact 120

has a fixed terminal 130 connected thereto and the movable contact 122 has a movable terminal 132 connected with the movable contact 122. Furthermore, as shown in FIG. 2, both the fixed terminal 130 and the moving terminal 132 extend outwardly from the back side 108 of the housing 102. The fixed terminal 130 is electrically coupled to a power supply (not shown) whereas the movable terminal 132 is electrically coupled to an electrical device (not shown), for example a motor, in known manner.
[0021] Reference will now be given to FIG. 3 that in conjunction with FIG. !
describes in detail the constructional features as well as the working principle of the vacuum contactor assembly 100. FIG. 3 illustrates a cross-sectional view of the vacuum contactor assembly 100 according to an embodiment of the present invention. As noted above, the upper section 114 of the housing 102 has the vacuum capsule 118 disposed therein. The vacuum capsule 118 has the fixed contact 120 and the movable contact 122 separably positioned against each other in spaced apart relationship. Preferably, the fixed contact 120 and the movable contact 122 are separated from each other by a distance of 4mm. Further, a portion 134 of the fixed contact 120 extends outside and is fixedly attached to an upper portion 136 of the housing 102 via fastening means 138, as shown in FIGS. 1 and 3. Alternatively, the fixed contact 120 may be fixedly disposed within the vacuum capsule 118, which in turn may be fixedly attached to the upper portion 136 of the housing 102 via the fastening means 138 and should be construed to be within the scope of the present invention. The movable contact 122 also extends outside from the vacuum casing and connected to a bushing 140, which acts as an insulating means via a stud 142 that fixedly holds the bushing 140 with the movable contact 122 during movement of the movable contact 122. Preferably, the bushing 140 has a front end 144, a back end 146, and a longitudinal portion 148 extending from the back end 146. The front end 144 is fixedly

connected to the movable contact 122 via the stud 142 and whereas, the longitudinal portion 148 extends outwardly from the back end 146. Further, a portion of the movable contact 122 that is positioned within the vacuum casing is disposed within a bellow 150 in vacuum environment. The bellow 150 provides flexibility to the movable contact 122 when the movable contact 122 demonstrates a reciprocating motion within the vacuum casing.
[0022] The actuating means 124 includes an electromagnet 152, acting as a
temporary magnet, fixedly disposed on a lower side of the intermediate plate 112 via a combination of a packing smc plate 154 (sheet mould component) and a back plate 156. Preferably, the electromagnet 152 is constructed by taking at least two coils 158 securely disposed within corresponding bobbins 160. The electromagnet 152 is then tightened to the back plate by corresponding fastening members 162 known in the art. The actuating means 124 also includes a moving magnet 164 positioned adjacent to the electromagnet 152 in spaced apart relationship. Preferably, the moving magnetl64 is positioned at a distance of 6mm from the electromagnet 152. One of the sides of the housing 102 has an electronic control box 166 disposed thereon and electrically connected with the electromagnet 152 to selectively generate magnetic flux. The electronic control box 166 has a voltage controller card, which reduces the voltage input after preset time, disposed that may be remotely, manually, or automatically controlled so as to logically control selective generation of the magnetic flux from the electromagnet 152. Further, the electronic control box 166 may be powered by an external source (not shown) or, from the power source providing power to the vacuum contactor assembly 100.
[0023] Further, as commonly known in the switching devices art, the electromagnet
152 is designed to produce magnetic flux that allows the moving magnet 164 to get biased towards the electromagnet in the vertical direction. Similarly, when the power supply to the

voltage controller card is stopped, the control voltage is goes to 0 voltages hence no flux produced & no force to attract the moving magnet. Therefore, the moving magnet 164 is released downwardly in the vertical direction. Thus, the moving magnet 164 is displaced between a biased position and a released position.
[0024] As shown in FIGS. 1 and 3, the mechanical linkage 126 comprises of a pair of
parallely arranged horizontal rods 168 and a pair of parallely arranged vertical rods 1 70 operably
connected with each other. As shown in FIGS. 1-3, the mechanical linkage 126 is coplanarly
arranged with the fixed contact 120 and the movable contact 122 and movable in the vertical
direction. A first horizontal rod 172 is disposed within the lower section 116 whereas a second
horizontal rod 174 is disposed within the upper section 114 of the housing 102. The first
horizontal rod 172 holds the moving magnet 164 thereon via a combination of a plurality of
fasteners 176 by means well known in the art. Further, the first horizontal rod 172 also has at
least one first guiding bush 178 attached thereto and slidably connected with a bottom portion
180 of the housing 102. The bottom portion of the housing 102 has a metallic guide pin 182
disposed thereon that receives the at least one first guiding bush 178 therein. The guide pin 182
is fixedly attached to the bottom portion via a guide pin holding bolt 184 for allowing the first
horizontal rod 172 to move when the moving magnet 164 displaces between the biased and
released positions. Thus, the first horizontal rod 172 also moves between the biased and the
released positions. In one embodiment, there may be more than one first guiding bush 178 and
their corresponding guide pins 182 provided in the first horizontal rod 172 and the lower section
of the housing 102, respectively. In another embodiment, the first horizontal rod 172 may be
constructed to have an accurate design having the moving magnet 164 disposed sufficiently in
the middle thereof. Such a design would allow the mass of the first horizontal rod J 72 to be

considerably reduced thereby lesser energy being consumed to displace the moving magnet 164 between biased and released positions.
[0025] The second horizontal bar 174 has an opening 186 formed therein that slidably
receives the longitudinal portion 148 of the bushing 140 therein in such a manner that the longitudinal portion 148 extends outside from the second horizontal bar. The longitudinal portion 148 is locked against the second horizontal rod 174 preferably by a locking nut 188. Preferably. the longitudinal portion 148 of the bushing 140 has a cut section 190 thereby defining clearance within the opening 186. Further, the opening 186 also houses a biasing member 192 through which the longitudinal portion 148 enters the opening 186. As shown in FIGS, I and 3, the pair of vertical rods 170 is fixedly connected with opposite ends 194 of the first and the second horizontal rods 172, 174 to define a rectangular framework. The intermediate plate 112 has a pair of holes 196 formed therein that has a corresponding second guiding bush 198 positioned therein so as to allow a corresponding vertical rod to movably pass therethrough. It will be noted by a skilled person in the art that the vertical rods 170 transfer the linear displacement of the first horizontal rod 172 to the second horizontal rod 174, which in turn transfers the displacement to the bushing 140 and the movable contact 122, respectively.
[0026] Preferably, a portion of each of the vertical rods 170 that are positioned within
the lower section 116 of the housing 102 are disposed to have another biasing member 200 adjacent thereof. The biasing member is seated between the second guiding bush 198 and its corresponding spring holder 202 that is locked by a fastening member 204. Preferably, the second guiding bush 198 has self lubricating liners 206 formed thereon so as to assist in smooth movement of the vertical rods 170 and to avoid zero play. This biasing member allows the vertical rod to move upwardly and. downwardly in controllable fashion and particularly.

downwardly in the released position when the moving magnet 164 moved from the biased position to the released position.
[0027] Reference will now be given to the working of the vacuum contactor assembly
100 with the help of FIG. 3. Preferably, the fixed contact 120 and the movable contact 122. in open condition, have been arranged to have a distance of 4mm between them. Further, the fixed contact 120 is kept at a potential of 7.2kV, 400A and the movable contact 122 is kept at 0KV potential thereby having a standard potential difference of 7.2kV, 400A therebetween. In order to complete the electric loop between the power source and the electric equipment (depending upon the switching requirements) during normal operation, the electromagnet 152 is operated to generate magnetic flux. As noted above, the magnetic flux exerts an attractive force, on the moving magnet 164 towards the electromagnet 152 and due to which the moving magnet 164 is displaced towards the electromagnet 152 in the vertical direction. The moving magnet 164 covers 4mm of spaced apart relationship between the electromagnet 152.
[0028] This displacement allows the first horizontal rod 172 to move along with the
moving magnet 164. This displacement causes the two vertical rods 170 to be displaced vertically, which in turn displaces the second horizontal rod 174. As the bushing 140 is fixedly connected to the second horizontal rod 174, the bushing 140 transfers this displacement to the movable contact 122. As a result of this, the movable contact 122 moved linearly against the fixed contact 120 and is electrically coupled with the fixed contact 120 in such a manner that the movable contact 122 just maintains a slight touch with the fixed contact 120. A person skilled in the art will appreciate that this linear movement of the movable contact 122 that is achieved by the vacuum contactor assembly 100 disclosed above in several embodiments does not introduces

unnecessary strain within the bellow 150 surrounding the movable contact 122. This is in sharp contrast with the prior art vacuum contactors.
[0029] The biasing member positioned in the opening of the second horizontal rod
174 and engaging the longitudinal portion 148 of the bushing 140 is chosen to have sufficient compressive strength and it does not gets compressed during the initial 4mm movement of the moving magnet 164. However, when the moving magnet 164 is further compressed to cover additional 2 mm so as to fully contact the electromagnet 152, the second horizontal rod 174 compresses the biasing member 192 so that the movable contact 122 is allowed to make tighi contact with the fixed contact 120 and ensuring lesser contact resistance. When the supply to the voltage controller card is stopped, as noted above, the moving magnet 164 moves to the released position. Thus, the second horizontal rod 174 is released in vertical direction from the electromagnet 152 thereby electrically separating the movable contact 122 from the fixed contact 120.
[0030] In some embodiments of the present invention, there may be more than one
vacuum capsules 118, having a corresponding fixed and movable contacts 120. 122 linearly interacting with each other, incorporated within the housing 102 so as to cater to the need of 3-phase vacuum contactors. A skilled person in the art would recognize that such constructing of 3-phase vacuum contactors based on the inventive concept, disclosed in the above several embodiments, would be an obvious modification and should be considered within the scope of the present invention.
[0031] It will be apparent to those, skilled in the art that various modifications and
variations can be made to the present invention without departing from the spirit and scope of the invention. Thus it is intended that the present invention cover the modifications and variations of

this invention provided they come within the scope of the appended claims and their equivalents.

We Claim:
I. A vacuum contactor assembly comprising: a housing;
at least one vacuum casing disposed within the housing and including a fixed contact and a movable contact separable from each other in spaced apart relationship, a portion of the movable contact protruding outwardly from the vacuum casing;
an actuating means disposed within the housing for allowing the movable contaci 10 open and close against the fixed contact, the actuating means including:
an electromagnet for selectively generating magnetic flux in its proximal areas; and
a moving magnet positioned adjacent to the electromagnet in spaced apart relationship and vertically displaceable between a biased position and a released position under the influence of the magnetic flux, the movable contact being electrically coupled to the fixed contact in the biased position and being electrically separated from the fixed contact in the released position; and
a mechanical linkage coplanarly arranged with the fixed and the movable contacts and including a pair of parallely arranged horizontal rods, a first horizontal rod fixedly connected to die moving magnet and dispiaceable between the biased and released positions whereas, ihe second horizontal rod is connected to the movable contact via an insulator, opposite ends of the first and the second horizontal rods being connected by a pair of parallely arranged vertical rods. wherein
the pair of vertical rods linearly transfers displacemem of the first horizontal rod to the movable contact via the second horizontal rod.

2. The vacuum contactor assembly according to claim !, wherein the first horizontal rod has ai
least one first guiding bush attached thereto, the guiding bush siidably connected with a guide
pin fixedly attached to a bottom portion of the housing for allowing the first horizontal rod to
move between the biased and released positions.
3. The vacuum contactor assembly according to claim 1, wherein the housing has an intermediate plate dividing the housing into an upper section and a bottom section, the upper section having the vacuum casing and the second horizontal rod disposed therein whereas, the bottom section having the actuating means and the first horizontal rod disposed therein, respectively.
4. The vacuum contactor assembly according to claim 3, wherein the intermediate plate has a pair of holes formed thereon, each of the pair of holes having a second guiding bush positioned therein so as to allow a corresponding vertical rod to movably pass through.
5. The vacuum contactor assembly according to claim 4, wherein each of the vertical rods pass through a corresponding biasing member positioned within the bottom section, the biasing member assisting in controlled displacement of the pair of vertical rods when the moving magnet is in biased position and released position, respectively.
6. The vacuum contactor assembly according to claim 1, wherein the insulator has a front end. a back end and a longitudinal portion extending from the back end, the top end fixedly connected to the movable contact whereas the longitudinal portion is siidably received within the opening.

end of the longitudinal portion received outside the opening is locked against the second horizontal rod by a locking nut.
7. The vacuum contactor assembly according to claim 6, wherein the longitudinal portion is inserted in a second biasing member seated between the back end and the opening, and wherein the longitudinal portion has a cut defining a clearance within the opening.
8. The vacuum contactor assembly according to claim 1, wherein an electronic control box is disposed on the housing, the electronic control box having a programmable logic disposed in electronic communication with the electromagnet for allowing selective generation of magnetic flux.