Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-02-18
2001-02-13
Enad, Elvin (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S058000, C310S059000, C310S06000A, C310S06000A, C310S064000, C310S065000
Reexamination Certificate
active
06188153
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a segmented stator end turn air deflector for a force ventilated AC motor and, more particularly, to a method and apparatus for directing the air flow of dynamo electric machines such as an AC electric motor or an alternator through the stator end turns for more efficient cooling.
Typical dynamo electric machines such as AC electric motors or alternators are formed of a rotatable rotor and a fixed stator. Stators are normally formed of a series of thin, flat plates stacked to form a solid body. Coils or windings are positioned in pre-formed slots in the plates, extending through the stack, with ends of the coils looping at each end of the stack to form end turns. The stator is normally cooled by air blowing through passages in the stator. Some air flows through the gap between the stator and the rotor. All of the air exits the machine through openings in an end of the housing (the “end bell”) supporting the stator. As the air exits in a longitudinal direction, very little of the air actually passes through the coil end turns.
In general, prior art methods and apparatuses for increasing the efficiency of force ventilated AC motors by more efficient cooling have been directed to methods suitable only for initial manufacturing. For example, U.S. Pat. No. 5,214,324 to Holmes describes a stator air baffle provided to redirect cooling air flow exiting the stator of an electric motor. The air baffle is provided at the air outlet end of the motor and extends between the stator frame and the stator coils so that air is redirected to pass through the coil end turns before exiting the motor. The baffle is fixed to the coils but is loosely mounted to the stator frame in a floating manner so that the entire assembly is free to rotate and can have limited longitudinal motion when necessary according to the operating condition of the motor.
U.S. Pat. No. 5,306,972 to Hokanson et al. describes an AC motor system having a rotor and a stator with the rotor having a plurality of air passages for passing cooling air and the stator having winding end turns extending from each end. An air deflector is coupled to one end of the rotor and has a generally curved configuration for directing cooling air exiting the air passages into a generally radial flow direction and onto the stator end windings. The stator end windings comprise turns of a plurality of electrical conductors forming the stator windings circuits which are wound to form a plurality of phase windings. Accordingly, the prior art has not disclosed a retrofittable baffle assembly which can be used to improve the efficiency of force ventilated AC motors.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a segmented stator end turn air deflector for a force ventilated AC motor which can be retrofitted into existing motors for redirecting air flowing through passages in a stator of the motor. In an exemplary form, a segmented stator end turn air deflector comprises a plurality of generally flat plates each having a trapezoidal shape with arcuate inner and outer edges for positioning within a cylindrical motor housing. Each plate has a single hole to enable the plate to be bolted to an existing bracket within the motor housing. The hole positions are such that the plates can be oriented perpendicular to the direction of air flow through the motor stator whereby air exiting the stator passages impinges on the plates and is directed radially inward of the motor and onto end turns of the motor coils or windings.
REFERENCES:
patent: 3819965 (1974-06-01), Schoendube
patent: 4072872 (1978-02-01), Gleichman
patent: 4442371 (1984-04-01), Utsunomiya et al.
patent: 4609840 (1986-09-01), Eats et al.
patent: 4766337 (1988-08-01), Parkinson et al.
patent: 5081384 (1992-01-01), Rausch
patent: 5177385 (1993-01-01), Cooper et al.
patent: 5214324 (1993-05-01), Holmes
patent: 5306972 (1994-04-01), Hokanson
patent: 5343101 (1994-08-01), Matani
patent: 5757094 (1998-05-01), Van Duyn
Breedlove Jill M.
Enad Elvin
General Electric Company
Rowold Carl A.
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