ELECTRIC MOTOR WITH FACILITY FOR LIQUID COOLING

• US 3,727,085 A
• Filed: 09/30/1971
• Issued: 04/10/1973
• Est. Priority Date: 09/30/1971
• Status: Expired due to Term

• Current Assignee: Peter B. Goetz, Wilbert E. Bullert
• Original Assignee: Peter B. Goetz, Wilbert E. Bullert
• Inventors: Goetz, Peter B., Bullert, Wilbert E.
• Primary Examiner(s): Skudy, R.
• Application Number:
  US05/185,016
• Time in Patent Office: 558 Days
• Field of Search: 310/54,53,55,57,58,86,87
• US Class Current: 310/54
• CPC Class Codes: F25B 31/008 by injecting a liquid
• CPC Class Codes: H02K 5/128 using air-gap sleeves or air-gap discs
• CPC Class Codes: H02K 9/197 in which the rotor or stator space is fluid-tight, e.g. to provide for different cooling media for rotor and stator
• CPC Class Codes: Y10S 174/19 in a dynamo-electric machine
• CPC Class Codes: Y10S 174/20 Stator

Abstract

A liquid cooled electric motor is disclosed having a rotor surrounded by a stator and separated from the stator by a gap. A sleeve of insulating non-magnetic material separates the rotor from the stator and divides the motor housing into a stator cavity and a rotor cavity. The stator cavity is filled with a vaporizable refrigerant to a level covering the stator windings of the motor. A porting structure connects the lower portion of the rotor cavity to the stator cavity such that liquid refrigerant fills the rotor cavity to a predetermined level. The refrigerant cools both the rotor and the stator; thereby providing large horsepower output with a minimum motor size.

Claims

1. An electric motor adapted to be cooled by a liquid which comprises a. a stator, b. a rotor mounted for rotation in the stator, the outer periphery of the rotor being spaced from the inner periphery of the stator to define a cylindrical gap there between, c. a housing including a jacket surrounding said stator, d. a cylindrical sleeve extending axially of said gap and defining a rotor cavity around said rotor and a stator cavity between said sleeve and said jacket, e. means for filling said stator cavity to a first predetermined level with said liquid, and f. means in said housing communicating the portion of said stator cavity filled with said liquid with said rotor cavity for filling said rotor cavity with said liquid to a second predetermined level lower than said first level.

2. The invention as set forth in claim 1 wherein said lIquid is a vaporized refrigerant of the class including fluorinated hydrocarbons.

3. The invention as set forth in claim 2 wherein said stator includes means for providing a radial vent therein, said vent extending from the outer periphery of said stator to the inner periphery thereof for providing a path for flow of said liquid and bubbles of the vapor of said liquid, said vent extending above said first predetermined level.

4. The invention as set forth in claim 3 wherein said vent providing means includes a plurality of radially extending bars disposed in the same plane.

5. The invention as set forth in claim 4 wherein said bars have a plurality of parts spaced radially from each other to provide lateral flow paths through said bars via the spaces therebetween.

6. The invention as set forth in claim 4 wherein said stator has a plurality of axial openings extending into said vents from the ends of said stator.

7. The invention as set forth in claim 4 wherein said stator has a plurality of axially extending slots for receiving windings, windings contained in said slots, said slots also having a section extending radially beyond the portion of said slots which contain said windings, said radial sections defining an axial slot communicating the ends of said stator with said vents.

8. The invention as set forth in claim 7 wherein said slots each have a pair of said sections, one extending toward the inner periphery of said stator and the other toward the outer periphery thereof.

9. The invention as set forth in claim 1 wherein said second predetermined level covers a sector of said rotor less than 180* around the lower periphery of said rotor.

10. The invention as set forth in claim 9 wherein said sector is less than 90* centered about the vertical center line of said rotor.

11. The invention as set forth in claim 1 wherein said means in said housing communicating said rotor and stator cavities includes a porting structure providing communication between said stator cavity and said rotor cavity.

12. The invention as set forth in claim 11 wherein said motor has end housings and said porting structure includes an opening in one of said end housings communicating the adjacent portions of said stator cavity and said rotor cavity.

13. The invention as set forth in claim 12 including a venting structure for vapors of said liquid, said venting structure communicating between the upper regions of both said stator cavity and said rotor cavity which lie above said first and second predetermined levels respectively.

14. The invention as set forth in claim 12 wherein at least one of said end housings has at least one drain opening disposed above the level of said operating structure opening for establishing the second predetermined level of said liquid in said rotor cavity.

15. The invention as set forth in claim 14 wherein each of said end housings has a separate one of said drain openings therein, the one of said end housings having said porting structure opening having its drain opening above the level of the drain opening in the other of said end housings.