Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-10-29
2001-09-11
Waks, Joseph (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S06000A, C310S061000
Reexamination Certificate
active
06288461
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an electric rotary machine in which a rotor winding is provided with an air gap pick-up type cooling structure.
For example, as disclosed in page 151 of “MANUFACTURING AND MAINTENANCE OF ELECTRIC MACHINE COIL” by H. Sequenz, issued by DEVELOPMENT COMPANY on Jan. 1, 1990, in this cooling structure, a plurality of plate-shaped conductors forming a winding conductor each have a plurality of through holes perforated therein and a plurality of V-shaped flow paths each permitting cooling gas to flow in the axial direction of the rotor core while allowing the cooling gas to flow in the radial direction are formed in the winding conductor.
However, an electric rotary machine employing the above-mentioned cooling structure could not increase a quantity of cooling gas flowing in the cooling gas flow paths even if a thermal load was increased according to increase of output. Therefore, the cooling performance could not be improved and output could not be increased. This reason is that dynamic pressure occurring on the entry side of the cooling gas flow paths and negative pressure occurring on the exhaust side are determined fixedly by an outer diameter and rotation numbers of the rotor. That is, the outer diameter of the rotor, in the case of two poles, is limited to about 1 m because of restriction on material strength thereof, and the revolution number is determined 3000 rpm or 3600 rpm.
Further, in an electric generator employing the above-mentioned cooling structure, heat transfer of the cooling gas could not be increased and the cooling performance could not be improved even if flow of the cooling gas was disturbed by making the inner side of the cooling gas flow paths concave and convex. This reason is that the temperature of cooling gas increases according to increase in flow resistance of the cooling gas and an increment of the heat transfer of the cooling gas is canceled with the temperature increase. Although it was desirable to increase a quantity of cooling gas, it could not be increased for the above-mentioned reasons.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an electric rotary machine which is able to increase the cooling performance without providing any specific means on cooling flow paths and without increasing a flow rate of cooling gas.
A basic feature of the present invention resides in that a plurality of plate-shaped conductors and a plurality of insulators sandwiched between the plurality of plate-shaped conductors each have a plurality of flow paths in which cooling gas introduced from the periphery of a rotor core flows in an axial direction of the rotor core while flowing in a radial direction of the rotor core, that is, a plurality of through holes for forming a plurality of V-shaped flow paths which extend in a radial direction of the rotor core while deviating in an axial direction of the rotor core, and the through holes are in a plurality of rows each placed in a width direction of the conductor and the V-shaped flow paths each branch in a plurality of rows each placed in the width direction of the conductor. According to the present invention, the cooling performance can be improved without providing the flow paths with any specific means and without increasing a flow rate of the cooling gas.
Further, in the present invention, a plurality of through holes or flow paths formed in at least a conductor of the second step from the bottom step and in a conductor of the top step, of the plurality of conductors are formed in one row in the width direction of the conductor. According to the present invention, flow path areas of the winding conductors at the bottom step and top step can be made large and a cooling gas flow resistance can be made small.
Further, in the present invention, the number of row, placed in the width direction of the conductor, of through holes or flow paths formed in a conductor or conductors on the lower step side, of the plurality of conductors is smaller than the number of row, placed in the width direction of the conductor, of through holes perforated or flow paths formed in a conductor or conductors on the upper step side. According to the present invention, even if the conductor is made so that the width becomes small and the thickness becomes large as it approaches to a bottom portion, a construction can be taken in which a plurality of through holes or flow paths can be arranged in a plurality of rows each placed in the width direction of the conductor.
Further, in the present invention a flow path area each of the plurality of through holes or flow paths formed in plurality of rows is set so that the following relation is established
0.2≦WH/WC≦0.7
where the width size of the conductor is WC, and the total size of width, in the width direction of the conductor, of the through hole or flow path formed in plurality of rows is WH. According to the present invention, current density does not becomes large and a heat generation amount does not increase.
Further, in the present invention a width size, in the width direction of the conductor, of a portion between the rows of said through holes or flow paths formed in plurality of rows is set so that the following relation is established
5≦LH/WL≦20
where the width size, in a length direction of the conductor, of the through hole or flow path formed in a plurality of rows the conductor is LH, and the width size, in the width direction of the conductor, of the portion between rows of the through hole or flow path formed in plurality of rows is WL. According to the present invention, such a problem can be avoided that current is concentrated on mounting root portions of ligament portions which are between the rows of the through holes or flow paths formed in a plurality of rows to increase heat generation concentration, and the heat resistance becomes large by rapid change in cross-section of the ligament portions, whereby the ligament portions does not work effectively as fins.
The width direction of conductor in the present invention means a direction opposite to two sides long in length of four sides forming a plane of the conductor. The longitudinal direction of the conductor means a direction opposite to two side short in length of the four sides forming a plane of the conductor.
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Kimoto Hiroshi
Miyakawa Kado
Mori Hideaki
Shibata Takashi
Sonobe Tadashi
Antonelli Terry Stout & Kraus LLP
Hitachi , Ltd.
Waks Joseph
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