Electrical connectors – Self aligning contact – Contact mounted in floating nonconductive holder
Reexamination Certificate
1997-11-04
2001-01-30
Donovan, Lincoln (Department: 2832)
Electrical connectors
Self aligning contact
Contact mounted in floating nonconductive holder
C439S378000
Reexamination Certificate
active
06179637
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the mounting of circuit interrupters into the individual cells of a switchgear or other electrical distribution devices. More particularly, an assembly is provided for automatic and multi-positioned secondary electrical connections between the circuit interrupter and switchgear with an adjustable alignment therebetween.
BACKGROUND OF THE INVENTION
When circuit breakers or other circuit interrupters are mounted in individual cells as drawout switchgear, the primary purpose is to provide a disconnect of the breaker from the line and load bus bars. There are, however, other connections to the breaker, such as for metering and data communication to a power monitoring system which processes and displays information, power to wind-up mechanisms, remote operator controls, wiring to meters from the current transformers and the like. These connections, often several dozen in quantity, must be disconnected when the breaker is removed from the cell and are usually referred to as secondary connections. One requirement of drawout switchgear is a test position in which the line and load connections are broken, but the secondary connections are closed, allowing the breaker to be tested without actual engagement to the main bus bars. Since engagement of the secondary connections is potentially necessary in two different positions, the secondary contacts must allow for the distance between positions. In the past this has been handled by providing sliding secondary contacts. However, they have involved the disadvantages of fragility and maintenance of slide alignments. It is difficult to provide proper alignment for engagement of the secondary connections as the circuit breaker is racked into the cell. Racking the circuit breaker through the test and operating positions in the cell also makes it difficult to maintain reliable electrical connections at each position.
Prior art switchgear often utilized fixed contact elements on the rear panel of the circuit breaker and rear wall of the cell. Misalignment between these two components could result in damage to the equipment and an increased need for customer repair work and maintenance support. The fixed contact elements also reduce the availability of interchanging different individual circuit breakers among the cells in the switchgear since the mounting had to be precise and thus required adjustments for proper mounting.
Another problem has been created by the standards promulgated by certain governmental agencies and municipalities which require that the secondary connections be made automatically. In some instances, equipment existing in the field must be retrofitted or replaced. Meeting these standards should not increase the cost and complexity of manufacturing as well as installing the circuit breaker. Preferably, the automatic secondary connections could be useable for retrofitting equipment already installed in the field.
A need exists for an automatic secondary connection between the circuit breaker and the cell of an electrical distribution device panel. Flexibility in the alignment between the mating pieces of a secondary connection should also be provided for more reliable connections. Preferably, the automatic secondary connection is adaptable to an inexpensive and simple installation method for equipment in the field.
SUMMARY OF THE INVENTION
The present invention provides an assembly for automatically mating a plug terminal attached to the exterior of a circuit breaker with a receptacle terminal attached to the interior of a switchgear cell to provide secondary connections therebetween. The assembly includes a plug having a generally planar body partially defined by a surface and opposing surface. A plug terminal is supported by the opposing surface of the plug. A mounting bracket is slidably affixed to the opposing surface of the plug. The bracket has an aperture to allow the plug terminal to extend therethrough. The bracket is secured in a fixed position to the exterior of the circuit breaker. The assembly includes means for automatically adjusting the position of the plug to provide proper alignment between the plug terminal and the receptacle terminal to form an electrical connection between the terminals which can be disengaged. The adjusting means is connected to the plug and bracket.
The inventive assembly can also include a receptacle having a generally planar body partially defined by a surface and opposing surface. A receptacle terminal is supported by the opposing surface of the receptacle. A cell bracket is slidably affixed to the opposing surface of the receptacle. The cell bracket has an aperture to allow the receptacle terminal to extend therethrough. The cell bracket is secured in a fixed position to the interior of the switchgear cell. The adjusting means can also be connected to the receptacle and cell bracket.
A method is also provided by the present invention for automatically making secondary connections between a circuit breaker and a switchgear cell. The circuit breaker has a plug terminal attached to its exterior and the switchgear cell has a receptacle terminal attached to its interior. The secondary connections are provided between the plug and receptacle terminals. The plug terminal has at least one guide pin and the receptacle terminal has a corresponding surface for affixing to the guide pin thereto. The method includes the steps of: engaging the guide pin of the plug and corresponding surface of the receptacle terminal; automatically sliding the position of the plug terminal relative to the receptacle terminal to provide proper alignment to form an electrical connection between the plug and receptacle terminals which can be disengaged; and mating the guide pin of the plug and corresponding surface of the receptacle terminal in a reversibly affixed connection.
The secondary connectors assembly of the present invention provides the ability to adapt existing switchgear cells and circuit breakers. The adaptation allows the circuit breaker to be interchangeable and increases the reliability of the systems and connections. The present invention removes the need to individually align cell parts and check circuit breakers parts for correct dimensions. Additionally, the present invention is field installable and after being installed does not require a manual connection between the cell and circuit breaker wiring. Connection between the cell wiring and the circuit breaker wiring is completely automatic per the requirements of ANSI C37.20.
The present invention also includes a method for adapting existing communications wiring and interlock protection wiring including the steps of removing the existing connection assembly from a circuit breaker, providing a new breaker connector capable of automatic separable connection to a cell connector, installing the new breaker connection assembly on the circuit breaker, removing the existing receptacle connector from the cell, providing a receptacle connector capable of automatic separable connection to the circuit breaker connector and installing the new cell receptacle assembly.
It is an object of the present invention to provide the ability to automatically connect secondary connections providing a more reliable connection.
Another object of the present invention is to provide the ability to easily and uniformly convert existing switchgear allowing interchangeable use of circuit breakers.
Still another object of the present invention is to provide increased durability and reliability of the secondary connections by providing automatic alignment and connection of the circuit breaker into the cell.
A further object of this invention is to reduce the maintenance costs associated with replacing worn or defective secondary connections by making the connection assemblies more durable.
Another object of the present invention is to provide user-friendly conversion kits to make retrofitting existing switchgear simple and less time consuming.
Other and further advantages, embodiments, variations and the like will be apparent to t
Lee Gregory Brent
Ratliff Larry Gene
Donovan Lincoln
Golden Larry I.
Irfan Kareem M.
Square D Company
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