FORM 2
The Patents Act 1970
(39 of 1970)
&
The Patent Rules 2003
COMPLETE SPECIFICATION
(See Section 10 and rule 13) TITLE OF THE INVENTION:
POWER CONTACT SYSTEM FOR SWITCHBOARDS
APPLICANT:
LARSEN & TOUBRO LIMITED
L&T House, Ballard Estate, P.O. Box No. 278,
Mumbai, 400 001, Maharashtra . INDIA.
PREAMBLE OF THE DESCRIPTION:
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

A) TECHNICAL FIELD
[0001] The present invention generally relates to switchboards and particularly it relates to an electrical contact system for switchboards. More particularly it relates to a power contact system with a draw-out mechanism for the switchboard.
B) BACKGROUND OF THE INVENTION
[0002] A switchboard is a device which is used for housing control apparatus, such as circuit breakers, motor starters etc. It divides the main current into smaller currents for further distribution and to provide switching, current protection, and metering for these various currents. The switch board includes two sections incoming or service section and a distribution section that provides power to feeder and branch circuits. The circuit breakers and protection devices are mounted inside these sections to provide over current protection.
[0003] The starter is a combination of electrical components which controls the electrical power and protects the electrical circuit during fault conditions. The switchboards includes a plurality of control apparatus units which are removably disposed within an associated housing to engage or electrically connect to bus bar which are disposed in the housing and which may be withdrawn to disengage or disconnect the apparatus units from the associated bus bars. Usually electrical contact systems are provided to engage and disengage the control apparatus.
- 1 APR 2009

[0004] In conventional contact systems, the electrical joint also moves with the contacts and flexible conductors. Hence the terminals also experience mechanical stress. This can cause deterioration of the electrical joint and hence there is a need for frequent maintenance. The solid conductors can not be used with these designs. More over the assembly time required to assemble these systems are more. Hence there is a need to provide a mechanism to draw-out the starters in the switchboard, without disturbing the terminals connected to it. Hence there is a need to provide a mechanism, wherein the modules in the switchboard can be easily drawn-out for regular inspection.
[0005] Hence there is a need to provide a power contact system with a draw-out mechanism for the modules or starters in the switchboard for maintenance. There is a further need reduce the assembly time to make the assembly of the system easy
C) OBJECTS OF THE INVENTION
[0006] The primary object of the present invention is to provide a draw-out type power contact system for starters in the switchboards.
[0007] Another object of the present invention is to provide a draw-out type power contact system for the switchboard to ensure safe connection of starter with the supply.


[0008] Yet another object of the present invention is to provide a draw-out type power contact system for starters in the switchboard to maintain a safe distance between the sources of power supply and the contact system in isolation condition. [0009] Yet another object of the present invention is to provide a draw-out type power contact system for switchboard which can be removed outside the switchboard and can be inserted back easily during maintenance.
[0010] Yet another object of the present invention is to provide a draw-out type power contact system for starters in the switchboard to reduce stress induced on the electrical terminations during operation of the contact system.
[0011] Yet another object of the present invention is to provide a draw-out type power contact system for switchboard to ensure modularity and flexibility of power contacts for different ratings using minimum components.
[0012] 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
[0013] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.


[0014] The various embodiments of the present invention provide a draw-out type power contact system for starters in the switchboards. A power contact system for switch boards is provided with a contact arm. One side of the contact arm is used for connection with an incoming power source. A modular contact housing is provided on each side of the arm. A contact is provided inside the modular contact housing. Several braids are connected at one end with the contacts in the modular contact housing. A fixed terminal is connected to other end of the braids. The vertical bus bars are provided in the modular contact housing at the right hand side unit. A left hand side unit is provided at the right hand side of the contact arm for connecting with a load. A customer terminal assembly is fixed to the fixed terminal housing. The contact arm travels by a fixed distance to move the modular contact housing to engage with the vertical bus bars. The contact arm is moved by the push operation of a mechanism in the starter.
[0015] According to one embodiment of the present invention, a draw-out type power contact system for starters in the switchboards has a contact arm with incoming and outgoing side, contacts housed on modular contact housing for each phase, module terminals housed in the fixed terminal, braids with the contacts on one side and terminal on another side, vertical busbars on incoming side and customer terminal fixed with fixed terminal housing. The contact system acts as a power interface between source and load. The contact system in the present invention provides an additional draw-out mechanism. It enables the operator to draw-out the starter from the switchboard easily in less time without disturbing the electrical terminations.


J0016] According to one embodiment of the present invention, the power contacts are housed in modular contact housing. For each phase, one modular contact housing assembly is fixed on the contact arm by one set of nut and bolt. The braids are brazed with the contacts on one side and with the terminal on another side. The module terminals are housed in fixed terminal housing which enables to terminate the cables from module side on it. The braids provide flexibility to the system. The same arrangement is provided on the right side of the module. The right side of the contact system is called as incoming side since this side provides connection with the source and source side is always taken as incoming side.
[0017] According to one embodiment of the present invention, equal number of modular contact housings are mounted on each side of the contact arm. The customer terminal assembly is fixed with the fixed terminal housing on the customer terminal mounting plate. Here customer cables coming from load are connected with customer terminals.
[0018] According to one embodiment of the present invention, the contact arm travels a fixed distance by a push provided by the mechanism or a lever. It also moves the modular housing assembly along with it. Due to this contacts move and get engaged with vertical bus bars on incoming side or source side r which acts as an alternating current source. Also, on the customer terminal side, contacts engage with the customer terminals which results in closing or making of the electrical circuit. The braids provide flexibility to the system. When contact moves no stress is developed on the electrical joint. Hence reliability of the system is enhanced.
1 APR 2009

[0019] Hence the power contact system for switchboard acts as a power interface between source and load and provides a smooth operation with a draw-out feature. It ensures safe connection of starter with the alternating current supply. It provides a separation between the power source and the contacts system in isolation condition. The starter can be removed outside the switchboard and can be inserted back when ever required. It induces less stress on the electrical termination during operation of the contact system. It ensures modularity and flexibility for different ratings using minimum components. Hence the assembly time required for assembling the contact system is very less.
[0020] According to the aspect of the present invention, the design of the system is such that no stress is produced during operation of the contact system on the electrical termination. Hence the unit using such contact system can be drawn-out easily. It improves the reliability of the system. It provides additional benefits like use of the solid conductors and use of more than one conductor in parallel combination.
[0021] According to another aspect of the present invention, the modularity and the flexibility for of the power contact system is increased for different Ratings. The rating of the system is increased by adding or changing minimum components.
E) BRIEF DESCRIPTION OF THE RAWINGS
[0022] 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:


[0023] FIG. I shows a perspective view of the contact arm assembly of draw-out type contact system for starters in the switchboard according to one embodiment of the present invention.
[0024] 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
[0025] 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.
[0026] The various embodiments of the present invention provide a draw-out type power contact system for starters in the switchboards. A power contact system for switch boards is provided with a contact arm. On the arm, several Modular Contact Housings are fixed depending on the requirement. For e.g. a 3 phase system will need total six Modular


V Contact Housings, 3 for incoming of supply and 3 for outgoing. Similarly, for DC two wire system total two Modular Contact Housings will be required. Any side of the arm can be used as incoming or outgoing side. A contact is provided inside the modular contact housing. Several braids are connected at one end with the contacts in the modular contact housing. A fixed terminal is connected to other end of the braids. The vertical bus bars are provided in the modular contact housing at the right hand side unit. A left hand side unit is provided at the right hand side of the contact arm for connecting with a load. A customer terminal assembly is fixed to the fixed terminal housing. The contact arm travels by a fixed distance to move the modular contact housing to engage with the vertical bus bars. The contact arm is moved by the push operation of a mechanism in the starter.
[0027] According to one embodiment of the present invention, a draw-out type power contact system for switchboards has a contact arm with incoming and outgoing side, contacts housed on modular contact housing for each phase, module terminals housed in the fixed terminal, braids with the contacts on one side and terminal on another side, vertical busbars on incoming side and customer terminal fixed with fixed terminal housing. The contact system acts as a power interface between source and load. The contact system in the present invention provides additional draw-out mechanism. It enables the operator to draw-out the unit from the switchboard easily in less time without disturbing the electrical terminations.


[0028] According to one embodiment of the present invention, the power contacts are housed in modular contact housing. For each phase one modular contact housing assembly is used and is fixed on the left side of the contact arm by one set of nut and bolt. The braids are brazed with the contacts on one side and with the terminal on another side. The module terminals are housed in fixed terminal housing which enables to terminate the cables from module side on it. The braids provide flexibility to the system. The same arrangement is provided on the right side of the module. Any of the sides of the contact arm can be connected to live busbars.
[0029] FIG. 1 shows a perspective view of the contact arm assembly of draw-out type contact system for switchboard according to one embodiment of the present invention. With respect to FIG. 1, the contacts 4 are housed in the modular contact housing 1. For each phase, one modular contact housing assembly 1 is used and is fixed on the left side of the contact arm 2. The contacts 4 are fixed to contact arm 2 by using a set of nut and bolt. The braids 3 are fixed to contacts 4 on one side and with the terminal 5 on another side. The module terminal 5 is housed in fixed terminal housing 6 which enables to terminate the cables from module side. The braids 3 provide flexibility to the system. All these components are mounted even on the right side of the contact arm 2. It is called as incoming side since it side provides connection with the source.
[0030] The power contact system for switchboards acts as a power interface between source and load and provides a smooth operation with a draw-out feature. It ensures safe connection of starter with the power supply. It provides a separation between the live bus bars and the contact system in isolation condition. The starter can be removed outside the
1 APR 2009

switchboard and can be inserted back whenever required. It induces less stress on the electrical termination during operation of the contact system. It ensures modularity and flexibility for different ratings using minimum components. Hence the assembly time required for assembling the contact system is very less.
G) ADVANTAGES OF THE INVENTION
[0031] The various embodiments of the present invention provide a power contact system for switchboards. The contact system acts as a power interface between source and load and provides a smooth operation with a draw-out feature. It ensures safe connection of starter with the power supply. It provides a separation between the power source and the contacts in isolation condition. The unit containing such contact system can be removed outside the switchboard and can be inserted back when ever required. It generates no stress on the electrical termination during operation of the contact system. It ensures modularity and flexibility for different ratings using minimum components. Hence the assembly time required for assembling the contact system is very less.
[0032] The system is such that no stress is produced during operation of the contact system on the electrical termination. It improves the reliability of the system. It provides additional benefits like use of the solid conductors and use of more than one conductor in parallel combination. The modularity and the flexibility for of the power contact system are increased for different ratings. The rating of the system is increased by adding or changing minimum components.


[0033] 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.

[0034] 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.
RAKESH PRABHU
Patent Agent
Date: March 30, 2008^ Place: Bangalore.

CLAIMS

What is claimed is:
1. a power contact system for switch boards comprising:
contact arm;
a right hand side unit provided at the left hand side of the contact arm for
connecting with an incoming power source;
a modular contact housing provided at the right hand side unit;
a contact provided inside the modular contact housing;
braids connected at one end with the contacts in the modular contact housing;
fixed terminal connected to other end of the braids;
vertical bus bars provided in the modular contact housing at the right hand side
unit;
a left hand side unit provided at the right hand side of the contact arm for
connecting with a load; and
a customer terminal assembly fixed to the fixed terminal housing;
wherein the contact arm travels by a fixed distance to move the modular contact
housing to engage with the vertical bus bars.

2. The system according to claim 1, wherein the contact arm is moved by the push
operation of a mechanism in the starter.