Passive, phase-change, stator winding end-turn cooled electric machine
First Claim
1. An electric machine comprising a rotor, a stator and a cooling jacket, the stator comprising an armature, a plurality of stator windings that pass through a plurality of stator slots, producing a plurality of stator winding end-turns at a distal end of the armature and a plurality of stator winding end-turns at a proximal end of the armature, wherein the machine further comprises:
- a hermetically-sealed chamber surrounding the stator winding end-turns;
at least one phase-change internal coolant within the hermetically-sealed chamber, the internal coolant having a liquid phase and a vapor phase;
a wicking means comprising the plurality of stator winding end-turns and a wicking matrix disposed between the cooling jacket and said stator winding end-turns to provide wicking action; and
means for vapor return.
6 Assignments
0 Petitions
Accused Products
Abstract
A device and method for substantially enhancing the cooling of electric machines, e.g., motors and generators, is described. A hermetically-sealed chamber surrounds electric wire winding end-turns at either end of the stator core, and contains at least one phase-change coolant. The coolant removes heat from the stator winding through the end-turns, where often temperatures are the greatest, through cyclical ebullition, whereby heat generated by the stator winding end-turns boils and, subsequently, vaporizes the liquid coolant. The hot, vaporized coolant is removed through at least one vapor return passage and collects, cools, and condenses on the stator cooling jacket, which removes heat from the vaporized coolant. The liquid condensate precipitates into a wicking matrix, which continuously returns the liquid condensate through capillarity to the liquid coolant pool that partially wets the wicking matrix and winding end-turns. Addition of a passive, phase-change cooling system at the stator winding end-turns substantially enhances cooling the machine, which can reduce the size, weight, and cost of machines, especially, e.g., linear-, switch reluctant-, variable reluctant-, induction-, rotary-, and permanent magnet-type machines, and can provide greater efficiency of operation, lower cost per power unit, and increased power density.
59 Citations
30 Claims
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1. An electric machine comprising a rotor, a stator and a cooling jacket, the stator comprising an armature, a plurality of stator windings that pass through a plurality of stator slots, producing a plurality of stator winding end-turns at a distal end of the armature and a plurality of stator winding end-turns at a proximal end of the armature, wherein the machine further comprises:
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a hermetically-sealed chamber surrounding the stator winding end-turns;
at least one phase-change internal coolant within the hermetically-sealed chamber, the internal coolant having a liquid phase and a vapor phase;
a wicking means comprising the plurality of stator winding end-turns and a wicking matrix disposed between the cooling jacket and said stator winding end-turns to provide wicking action; and
means for vapor return. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for passively cooling an electric machine, which machine comprises a cooling jacket and a stator that, further, comprises an armature, a plurality of stator windings, which pass through a plurality of stator slots, a plurality of stator winding end-turns at a distal end and a proximal end of the armature, comprising the steps:
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hermetically encasing the plurality of stator winding end-turns in a chamber;
wetting the plurality of stator winding end-turns partially in a liquid coolant;
heating the liquid coolant to a boiling point to produce a vaporized coolant;
transporting the vaporized coolant through at least one vapor flow passage to the cooling jacket;
condensing the vaporized coolant at the cooling jacket, wherein the condensed, vaporized coolant becomes a liquid condensate as heat is transferred from the vaporized coolant to the cooling jacket;
collecting the liquid condensate in a wicking matrix, wherein the wicking matrix includes the plurality of stator windings end-turns; and
replenishing the liquid coolant at the end-turns by passing the condensate through the wicking matrix. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification