Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1995-05-31
1997-06-10
Dougherty, Thomas M.
Electrical generator or motor structure
Dynamoelectric
Rotary
310216, H02K 1716
Patent
active
056379439
DESCRIPTION:
BRIEF SUMMARY
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the priority of PCT Application PCT/AT93/00181 (Publication No. WO 94/13054, filed Dec. 1, 1993, which in turn claims the priority of Austrian Application No. A 2368/92, filed Dec. 1, 1992, the disclosures of which are incorporated herein by reference in their entireties.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention pertains to a squirrel-cage rotor having closed grooves extending along the circumference of the rotor, in which a squirrel cage rotor, with closed grooves extending along the circumference of the rotor, in which grooves, via the introduction of aluminum, aluminum conductor rods are produced, with the conductor rods filling out the grooves, wherein the groove cross section includes noses that extend into ideally-deemed groove cross sections, and bulges extend from the ideally-deemed groove cross sections.
2. Discussion of the Background of the Invention and Material Information
Asynchronous machines, with squirrel-cage rotors, due to their great advantages, such as, for example, low acquisition costs and low operating costs, ready adaptability to a large number of differing machines, as well as low maintenance, enjoy a broad distribution. These are usable in those instances having only low requirements relative to revolution, stability and speed range. In the start up phase generally no additional actuators are required.
In rotors having aluminum-compression or centrifugally cast squirrel-cages in the revolution range over 6000Rpm, it is a common occurrence that the rotors become imbalanced due to the shifting or displacement of the conductor rods in their grooves. Such shifts or displacements of the conductor rods already occurs either during the cooling of the aluminum, due to the considerable shrinkage thereof, or during high speed operation.
German Patent Publication DE, B, 1 190 094 describes an attachment of rods in the squirrel-cage rotor of electrical machines, in which embossed noses are provided on the rods, which fit into corresponding recesses in the rod grooves.
U.S. Pat. No. 2,350,012 describes a rotor having closed grooves which includes noses that extend into the groove thereby significantly varying the tooth width between the grooves.
It is the task of the invention to produce, with simple means, a squirrel-cage rotor whose conductor rods are so fixed in place that, even at very high speed operation, no imbalance can occur.
SUMMARY OF THE INVENTION
This task is achieved via this invention. The squirrel-cage rotor is therein characterized, that the ideally-deemed or theoretically ideal groove cross section, in the radial direction, is divided into at least two groove zones and that the groove zones are alternately displaced in and against the direction of the rotor, so that the width of the tooth, between two neighboring grooves, remains the same over the entire height of the groove.
Specifically, one embodiment of this invention pertains to a squirrel cage rotor, having closed grooves extending along the circumference of the rotor, in which grooves, via the introduction of aluminum, aluminum conductor rods are produced, with the conductor rods filling out the grooves, wherein the groove cross section includes protuberances that extend into theoretically ideal groove cross sections, and bulges that extend from the theoretically ideal groove cross sections, with each groove cross section, in the radial direction, being divided into at least two groove zones wherein the groove zones, with reference to the theoretically ideal groove cross sections, being alternately displaced in and against the direction of rotation of the rotor, so that each conductor rod is fixed in place both upon cooling of the aluminum as well as at high rotational rotor speeds, with the width of a tooth, between two neighboring grooves, remaining the same over the entire extent of the groove.
In a further embodiment of the squirrel cage rotor of this invention, the protuberances and the bulges are of substantially si
REFERENCES:
patent: 2350012 (1944-05-01), Brady
patent: 3137800 (1964-06-01), Young
patent: 3778652 (1973-12-01), Endress
patent: 3832583 (1974-08-01), Chang
patent: 4559463 (1985-12-01), Kobayashi
patent: 4782260 (1988-11-01), Gandhi et al.
The Patent Abstracts of Japan, p. 91 E 848, No. 61-92143 (Matsushita).
The Patent Abstracts of Japan, p. 91 E 848, No. 01-209940 (Matsushita).
Dougherty Thomas M.
Elin Motoren
Link Jonathan
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