Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2004-03-17
2004-12-14
Dougherty, Thomas M. (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S086000, C310S049540, C310S058000, C310S06800R, C310S071000
Reexamination Certificate
active
06831382
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to dynamoelectric machines, and in particular to a cover which is removably mounted to an endshield of a motor and which simultaneously seals against the endshield and provides unhindered access to fasteners for connecting the machine to an adjacent part, such as a pump.
Dynamoelectric machines such as electric motors have widespread use in converting energy between electrical current and mechanical motion. A substantial concern is that motors are frequently exposed to contaminants such as moisture and dust which damage or degrade the motors. Electrical component parts used in control and operation of the motors are particularly vulnerable to damage from water, which can produce short-circuits and safety hazards. Consequently, electronic components are mounted at locations where they may be protected from environmental contamination. For example, a motor for an above-the-ground swimming pool filter pump is typically placed outdoors, adjacent to the pool, where it is exposed to both rain and splashes. The motor has an electric power cord with wires that connect at a terminal board holding electronic components. The terminal board is mounted inside the motor behind a sealed cover to prevent moisture from reaching the terminal board or its components, thereby lowering the risk of contamination. Typically, the cover includes a steel plate and gasket which are mounted to an endshield of the motor using two or more small threaded fasteners. Unfortunately, removal and replacement of that cover increases the time required to access the terminal board for assembly or maintenance, thereby degrading efficiency.
Some motors have a dome-type cover which encloses a portion of the endshield, but these covers have the drawback of requiring additional installation time during assembly. Either they fail to provide an effective seal so that a second, steel plate cover is still required, or alternatively they obstruct access to bolt fasteners used in connecting the motor to an adjacent part, such as a pump or support. In the latter instance, the dome-type cover must be removed for manipulating the bolt fasteners even though there is no need to access the terminal board or electronic components. That exposes the electronics to potential contamination during the time when the cover is removed. More importantly, a person may inadvertently damage electronic components when removing or re-installing the cover, or may inadvertently re-install the cover at an unsealing, mis-aligned orientation, causing subsequent leaks and damage.
SUMMARY OF THE INVENTION
Among the several objects and features of the present invention may be noted the provision of a dynamoelectric machine which is connectable to an adjacent part while being simultaneously protected from moisture or contaminants; the provision of such a machine which reduces the time required for connection to the adjacent part; the provision of such a machine which has an effective seal; the provision of such a machine which provides unhindered access to fasteners; the provision of such a machine which reduces risk of damage to electronic components; and the provision of such a machine which is economical.
In general, a dynamoelectric machine of the present invention is connectable to an adjacent part while being simultaneously protected from moisture or contaminants. The machine comprises a casing having a hollow interior defining a housing and a longitudinal axis. An endshield is positioned generally at an end of the casing and mounts at least one electrical component used in operation of the machine. The endshield has a wall projecting in a longitudinal direction and further has at least two openings for receiving fasteners to connect the machine to the adjacent part. The at least two openings define respective fastening locations on the endshield. A cover is removably mounted on the endshield and defines an enclosure to protect the at least one electrical component. The cover is configured for an overlapping fit with at least a portion of the wall of the endshield to prevent passage of moisture or contaminants into the enclosure. The cover is further configured to avoid covering the at least two openings when mounted on the endshield such that the fastener locations lie outside of the enclosure and are accessible for connecting the machine to the adjacent part while the cover remains mounted on the endshield.
In another aspect, a method according to the present invention protects a dynamoelectric machine from moisture or contaminants while connecting the machine to an adjacent part. The machine has a casing, two opposite endshields, and at least two fasteners connecting the endshields and extending beyond the casing for connection to the adjacent part. The method comprises the steps of mounting a cover on a portion of one of the endshields with a fit which overlaps a sidewall of the endshield to prevent passage of moisture or contaminants. The cover is configured to avoid covering the fasteners. The fasteners are manipulated to connect the machine to the adjacent part while the cover remains mounted on the endshield.
Other objects and features of the present invention will be in part apparent and in part pointed out hereinafter.
REFERENCES:
patent: 4593163 (1986-06-01), Fisher
patent: 4716326 (1987-12-01), Fisher
patent: 4858303 (1989-08-01), Fisher
patent: 5006743 (1991-04-01), King et al.
patent: 5245237 (1993-09-01), Fisher
patent: 5278469 (1994-01-01), Weber
patent: 5861689 (1999-01-01), Snider
patent: 6472785 (2002-10-01), Petit
patent: 6559566 (2003-05-01), Modi
patent: 6657338 (2003-12-01), Fisher
A.O. Smith Electrical Products Company, Century Flex-48 Pool & Spa Assembly, Drawing and Four (4) photographs, undated.
Five (5) photographs of cover for motor, undated, made by A.O. Smith Electrical Products Company.
Druhe Timothy J.
Lyle David M.
Dougherty Thomas M.
Emerson Electric Co.
Mohandesi Iraj A.
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