FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
&
PATENTS RULES, 2006
COMPLETE SPECIFICATION
(SECTION 10; RULE 13)
"TERMINATION OF DC LINK CAPACITORS"
ALCON ELECTRONICS PVT. LTD., A COMPANY INCORPORATED UNDER THE COMPANIES ACT, 1956, HAVING ITS REGD. OFFICE AT 34-B, MIDC, INDUSTRIAL ESTATE, STAPUR, NASHIK- 422 007, MAHARASHTRA, INDIA.
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

Technical Field:
The present invention relates to terminations in capacitors. Particularly, the present invention relates to terminations in dc link capacitor.
Background:
Capacitors known in the prior art, which are used as dc link capacitor in power electronics are described with reference to figure 1, wherein the same numerals denote the same parts and wherein:
Figure la) shows cross sectional view of the capacitor known in the prior art.
Figure lb) shows the schematic of the capacitor assembly known in the prior art,
which discloses termination between element.
Figure lc) shows the schematic of internally terminated assembly known in the prior
art with external terminal bakelite disc.
Figure 1(d) shows cross sectional view of the internal termination of the capacitor
assembly known in the prior art.
Figure 1(e) shows the schematic of the capacitor potted in capacitor housing
Figure 1(0 shows the schematic of the finished capacitor.
Figure 1(g) shows the cross sectional view of the potted capacitor assembly.
Figure 1 (h) shows sealed capacitor assembly .

As shown in figure 1(a) the capacitor consists of a capacitor housing (2), terminal regions (la), (lb), insulating PVC sheet (3), electrically isolating the capacitor element (4) from capacitor housing (2). Figure 1(d) shows capacitor elements (4), internally connected in parallel and finally terminated to external terminal bakelite disc (1). This termination is done by riveting terminals 5(a), 5(b) to the bottom side of external terminations 1(a) and 1(b). Fig 1(b) shows termination between element and figure 1(c) shows termination to external terminal bakelite disc (1). Assembly [ref fig 1(c)] is potted in capacitor housing (2) [ref fig 1(a)] with flame retardant epoxy. (Ref fig 1(e)).
The whole assembly is sealed, which forms the finished capacitor, as shown in Figure 1(f). Due to aforesaid construction, an electrical loop is formed between point 5(a) & 5(b). This loop offers a self inductance. This self inductance of the capacitor causes self heating of the capacitor. Heating of the capacitor, substantially reduce operational life of the capacitor.
Object of the invention:
The present invention obviates the aforesaid drawbacks by reducing the inductance of the capacitor assembly by improving the termination of the capacitor.
Summary of the invention:
The present invention relates to a DC Link capacitor comprising of (i) at least two capacitor elements connected in parallel using conducting strips, preferably copper

strips, wherein terminals of the capacitor elements are connected to the conducting strips by soldering or welding. Insulating tape is used between the capacitor elements and the copper strips. The aforesaid mechanism results in reducing the self inductance of the termination of the capacitor.
Detailed description of the invention:
The present invention will now be described with reference to Figure (2) wherein the same numerals relate to the same parts:
Figure 2(a) shows the line diagram of the capacitor. Figures 2(b) to 2{d) show the schematic of the capacitor. Figure 2(e) shows the schematic of the capacitor with mica disc. Figures 2(f) and 2(g) show the schematic of the capacitor. Figure 2(h) shows the schematic of the finished capacitor.
The present invention relates to a DC Link capacitor comprising of (i) at least two capacitor elements connected in parallel using conducting strips, preferably copper strips, wherein terminals of the capacitor elements are connected to the conducting strips by soldering or welding. Insulating tape is used between the capacitor elements and the copper strips. The aforesaid mechanism results in reducing the self inductance of the termination of the capacitor.

A preferred embodiment of the present invention has been described herein wherein two (2) capacitor elements are connected in parallel.
Referring to the Figures 2(b) and 2(c), external stud terminals (1) and (2) are either soldered or welded to copper strip. Insulating material, like Polyster tape is used for . isolation between copper strip (3) and the capacitor element (4).
Before potting, the whole assembly is wrapped with PVC sheet (Ref fig, 2(d)). The PVC sheet provides electrical isolation between the capacitor element assembly and the capacitor housing in radial direction. Mica disc (5) is inserted at the bottom of the capacitor housing. Mica disc provides electrical isolation between capacitor element assembly and capacitor housing in axial direction (Refer fig 2(e)).
Polypropylene top cover is inserted on to the capacitor housing. External stud terminals appear outside of the polypropylene top cover (6). The entire capacitor assembly is encapsulated with flame retardant epoxy. Epoxy is poured through holes provided on polypropylene top cover. Top cover holes are covered with self locking caps. Figure 2 (g) and 2(h) shows finished capacitor.
The aforesaid construction reduces the self inductance of the termination considerably; hence improves the operational life of the capacitor. The aforesaid construction reduces the self inductance of the terminations considerably.

Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding, the scope of the claimed invention. It should be emphasized that the above-described embodiments of the present invention, particularly any "preferred" embodiments, are merely possible examples of the invention of implementations, merely set forth for a clear understanding of the principles of the invention. Accordingly, it is to be understood that the drawings and descriptions herein are preferred by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.

We Claim:
1. A DC Link capacitor comprising of:
(i) at least two capacitor elements connected in parallel using conducting
strips; (ii) terminals of said capacitor elements connected to said conducting
strips by soldering or welding; (iii) insulating tape between said capacitor elements and said conducting
strips;
such that self inductance of the termination of said capacitor is
reduced.
2. A DC Link capacitor as claimed in Claim 1 wherein said conducting strip is made of electro copper.
3. A DC Link capacitor as claimed in Claim 1 or 2 wherein capacitor is encapsulated with epoxy poured from holes provided on top of the cover of said encapsulated capacitor.
4. A DC Link capacitor as claimed in any of the aforesaid claims wherein mica disc is connected to the bottom of said capacitor.
5. A capacitor assembly as herein described with reference to the drawings accompanying the specification.