A) TECHNICAL FIELD
[0001] The present invention generally relates to electrical devices such as draw out type meters, relays, instrument transformers like current transformers. The present invention particularly relates to the electrical terminals in meters, relays, current transformers, etc., and more particularly to shorting links in meters, relays.
B) BACKGROUND OF THE INVENTION
[0002] The shorting links are provided in meters/relays used in electrical power distribution systems. When the load is removed from a current transformer which remains coupled to an active power circuit, the voltage in the secondary winding of the transformer will soar and may saturate the CTs, which will result in malfunctioning. Accordingly, shorting blocks are used to provide a path for the current in the secondary winding to circulate.
[0003] During the manufacture or assembly of an electrical connector, it is often necessary to short two or more pins or contacts together so that the pins or contacts are attached to an earth lead through a single connection which is formed by soldering the rear end of each pin or socket contact which is to be shorted. But this method of shorting is laborious and the resulting network of junctions formed at the rear end of the insulating connector may obstruct the connections of the other leads to the individual unshorted plug pins or socket contacts.

[0004] The currently available draw out type meter or relays has a shorting link so that the current terminals that feed current to the module should get shorted automatically to prevent damage to the current transformers, when a draw out module is removed. All known designs of such products use a pair of terminals for feeding current and another pair of spring loaded contacts to short the path when draw out module is removed. A plastic rib is normally used to operate the shorting link.
[0005] The US patent 5994989 discloses an electrical shorting block for an electrical power distribution system. The shorting block has a molded member provided with recesses to receive the terminals having the apertures. A shorting bar is extended across the terminal members and is provided with apertures that are aligned with the apertures in the terminals. The shorting connectors are received in the apertures. The biased by the compression springs to move away from the terminals during non use period.
[0006] The US patent 4225839 discloses a current transformer encapsulated in an injection molded layer and provided with inverted U shaped shorting bar so that the central portion of the bar is rotatably mounted on the upper portion of the central support.
[0007] The US patent 5061 196 discloses a shorting link provided with legs that interlock with the contacts of an electrical connector. The contacts may be connected by the links to the ground.

[0008] The US patent 5248 953 discloses a thermal overload protection device for electronic components used in telecommunication and data transmission fields. The overload device has a spring elastic shorting link and a melting element so that the shorting link is tripped based on the fusing process of the melting element.
[0009] Thus none of the draw out type meters, relays and current transformers is provided with a compact, cheap and reliable shorting link. Hence there is a need to develop a current terminal with a built in shorting link to provide a compact and cost effective shorting link for the draw out type meter and relays.
C) OBJECT OF THE INVENTION
[0010] The primary object of the invention is to develop a built-in shorting link for current terminals in the draw out type meter or relay.
[0011] Another object of the invention is to provide a single contact assembly for connectors and shorting link.
[0012] Yet another object of the invention is to develop a shorting link for make-before-break contacts in draw out type energy meters.
[0013] Yet another object of the invention is to develop a draw out type energy meter with built in contact link for contact terminals thereby reducing the cost and space.

[0014] Yet another object of the invention is to develop a compact shorting link to reduce the size and cost of the device.
[0015] These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
D) SUMMARY OF THE INVENTION
[0016] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.
[0017] The various embodiments of the invention provide a current terminal with additional shorting finger for energy meter to short the current terminals when the energy meter is in removed condition.
[0018] According to one embodiment of the present invention, a draw out type meter is provided with a pair of current terminals in a complimentary mode. An additional finger is added to one side of the current terminals. When the current terminals are mounted in complementary mode, the additional fingers attached to the current terminals are made to contact each other to act as the shorting link. When the energy meter is mounted on the panel, the current terminals are engaged with the female terminals provided in the panel to complete the circuit. An insulator provided in the meter is inserted between the additional fingers to prevent the shorting. The insulator provided between the male terminals on meter does the job of opening the shorting

link. Thus the need for an additional pair of contacts and the plastic mechanism are eliminated thereby saving cost and space.
E) BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:
[0020] FIGURE. 1 illustrates a top perspective view of the female contact terminals arranged in the energy meter along with the mating male connector, according to one embodiment of the present invention.
[0021] FIGURE. 2 illustrates two different perspective views of female contact terminal for draw out type energy meter according to one embodiment of the present invention.
[0022] FIGURE. 3 illustrates a perspective and enlarged view of the female contact terminal mounted on a panel of meter module according to one embodiment of the present invention.
[0023] FIGURE. 4 illustrates a partial perspective and enlarged view of the male and female contact assembly for energy meters according to one embodiment of the present invention.

[0024] FIGURE. 5 illustrates a top perspective view of the male and female contact assembly before contact according to one embodiment of the present invention.
[0025] FIGURE. 6 illustrates a top perspective view of the male and female assemblies in contact according to one embodiment of the present invention.
[0026] Although specific features of the present invention are shown in some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.
F) DETAILED DESCRIPTION OF THE INVENTION
[0027] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.
[0028] The various embodiments of the present invention provide a draw out type energy meter with in built shorting link to close the electrical contact terminals when the energy meter is removed from the panel.

[0029] According to one embodiment of the invention, plurality of female contact terminals with built in shorting links are provided in an energy meter. The terminal corresponding to each phase is provided with a pair of female contact terminals arranged in a complimentary manner. Each female contact terminal is provided with an additional finger at the sides so that the additional finger acts as a shorting link. Two female connectors are assembled in opposite directions or in a complimentary manner so that the additional fingers of both the female terminals are arranged to contact each other to provide a positive contact and to short the female terminals when the energy meters are in draw out condition.
[0030] Plurality of female terminals are mounted on a panel and connected to the current transformers for mating with the male contact terminals mounted on the energy meter. The male terminals in the energy meter are made to engage with the female terminals in the panel to supply power to the energy meter, when the energy meter is mounted on the panel. An insulator terminal provided between the male terminals is inserted between the two additional fingers to isolate the additional fingers to break the contact between the additional fingers so that the positive connection is established between the male and the female terminals to complete a current supply path. When the energy meter is removed from the panel, the male terminals are disconnected from the female terminals and the insulator is moved away from the additional fingers so that the additional fingers are made to contact each other to provide a shorting path.
[0031] The terminals feeding current to the draw-out modules which may include meters and relays should be shorted when the modules are drawn-out. The additional

fingers make a positive contact providing shorting in the make-before-break assembly. The main contact is broken only after the additional fingers make a positive contact.
[0032] FIGURE. 1 illustrates a top perspective view of the female contact terminals arranged in the energy meter along with the mating male connector, according to one embodiment of the present invention. With respect to FIG.l, a male contact terminal 1 is provided in a panel at the back of an energy meter to supply power to the energy meter when a draw out type energy meter is mounted on the panel. A female terminal 2 is mounted on the panel to engage with the male terminal 1 in the meter to complete an electrical circuit. The female contact terminal 2 is provided with an additional finger 5 at one side. The additional finger 5 acts as a shorting link, when the female terminal 2 is disengaged from the male terminal Ivafter the removal of the energy meter from the panel or the energy meter is in draw out condition, When two female terminals 2 are arranged in complimentary maimer, the additional fingers 5 of both the female terminals 2 are made to contact each other to provide a shorting path.
[0033] FIGURE. 2 illustrates two different perspective views of female contact terminal 2 for draw out type energy meter according to one embodiment of the present invention. With respect to FIG.2, a female terminal 2 has a base portion 3 for receiving the connections from secondary of current transformer (CT). Two resilient arms 4 are connected to the base 3 to receive a male terminal, when the energy meter is mounted on a panel. An additional finger 5 is coupled to one arm 4 to act as a shorting link, when the energy meter is in draw out condition. The female terminals 2 are arranged in complimentary mode so that the additional fingers 5 of two female

contact terminals 2 are arranged to contact each other to provide a shorting link, when the energy meter is in draw out condition.
[0034] FIGURE. 3 illustrates the perspective and enlarged views of the female connector assembly 6 mounted on an energy meter according to an embodiment of the invention. With respect to FIG.3, the female connector assembly 6 is provided with pluralities of the pairs of female contact terminals. Each pair of terminals corresponds to a phase current. The pair of female contact terminals 2 are mounted in complementary positions so that the additional fingers of each terminal is made to contact each other to provide a shorting link, when the energy meter is in draw out mode. The additional fingers 5 of the adjacent contacts 2 make a positive contact to form the shorting link in the drawn-out position of the module.
[0035] FIGURE. 4 illustrates the exploded perspective and enlarged views of the connector assembly including a male contact assembly 7 and a female contact assembly 6. With respect to FIG.4, the female contact assembly 6 is mounted on a panel provided to supply power to the energy meter in draw in mode. The male contact assembly 7 is mounted on the panel at the back of the energy meter to engage with the female contact assembly 6 provided in the panel to supply power to the energy meter, when the energy meter is mounted on the panel. The male contact assembly 7 includes a pair of male terminals that are inserted into the female contact terminals to complete an electrical connection. An insulator 8 provided between the pair of male terminals in the male contact assembly 7 is inserted between the adjacent two additional fingers in the female contact assembly 6 to isolate the two additional fingers, when the energy meter is in drawn in condition.

[0036] FIGURE. 5 illustrates the top perspective view of the female contact assembly 6 and the male contact assembly 7 before contact, while FIGURE. 6 illustrates the top perspective view of male contact assembly 7 and female contact assembly after the contact, with respect to FIG.5, The female contact terminals in the female contact assembly are arranged in a complimentary manner so that the additional fingers 5 of the adjacent female terminals contact each other to provide a positive contact and to act as shorting link to earth the terminals, when the energy meter is draw out condition. During the cormection process or when the energy meter is pushed in, the male contacts provided in the energy meter are inserted into the female contacts at the panel to establish an electrical connection as shown in FIG.6. The insulator provided between the male contact terminals are inserted into the adjacent two additional fingers to isolate the additional fingers thereby preventing the shorting of the links, when the energy meter is pushed in.
G) ADVANTAGES OF THE INVENTION
[0037] The embodiments of the present invention provide a current terminal widi a built in shorting link so that installation space and the cost are reduced. An additional finger is attached to one side of the female contact thereby eliminating the need for an additional pair of contacts and the plastic mechanism to save the cost and to reduce the size of the device.
[0038] Although the invention is described with various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims.

[0039] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the present invention described herein and all the statements of the scope of the invention which as a matter of language might be said to fall there between.

Date: November 27, 2008. RAKESH PRABHU
Place: Bangalore. Patent Agent

CLAIMS
1. Current terminal for draw out type meter comprising:
male contact terminal assembly provided in energy meter;
female contact terminal assembly provided in panel in which energy meter is mounted, to engage with the male contact terminal assembly; wherein the female contact terminal is provided with additional finger to act as shorting link, when the energy meter is in draw out mode.
2. The terminal according to claim 1, wherein the additional finger is attached to one side arm of the female contact terminal.
3. The terminal according to claim 1, wherein the female terminals are assembled in opposite directions so that the additional fingers attached to both the terminals rest on each other to make positive contacts, when the meter is in draw out condition.
4. The terminal according to claim 1, wherein the male contact terminal assembly includes male terminals to engage with the female terminals in the female contact assembly to make contacts, when the energy meter is in draw in condition.
5. The terminal assembly according to claim 1, wherein the male contact assembly has insulator provided between two adjacent male terminals.

6. The terminal assembly according to claim 1, wherein the insulator is interposed between the two additional fingers to isolate the additional fingers to break the contact between the additional fingers, when the energy meter is in draw in condition.