Grounding of outer winding insulation to cores in dynamoelectric machines

• US 4,001,616 A
• Filed: 02/10/1975
• Issued: 01/04/1977
• Est. Priority Date: 02/18/1974
• Status: Expired due to Term

• Current Assignee: Canadian General Electric Co Ltd (General Electric Company)
• Original Assignee: Canadian General Electric Co Ltd (General Electric Company)
• Inventors: Lonseth, Palmer, Panter, Hubert Gerald, Selkirk, Neil Robertson
• Primary Examiner(s): Skudy, R.
• Application Number:
  US05/548,835
• Time in Patent Office: 694 Days
• Field of Search: 310/194, 310/45, 310/196, 310/215, 310/260, 310/270, 310/208, 310/156, 336/223, 336/DIG. 1, 428/323, 174/102 SC, 174/110
• US Class Current: 310/45
• CPC Class Codes: H02K 3/40 for high voltage, e.g. affording protection against corona discharges
• CPC Class Codes: Y10S 174/20 Stator
• CPC Class Codes: Y10S 174/28 Plural semiconductive layers
• CPC Class Codes: Y10S 174/30 having insulation with a particular dimension or geometry
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles

Abstract

According to the invention electrically conductive paths are provided between the coil armor and the core laminations of dynamoelectric machines by placing a semiconducting elastomeric material between the coil sides and the walls of the core slots. The elastomeric material is of a type which has a controlled resistance and will deform sufficiently under pressure to flow into the irregularities between the coil side and the slot walls, and in so doing provide conductive paths for electric charge to flow from the armor to the core laminations. This material must be capable of retaining its strength, elasticity, conductivity, etc., and remaining in place between the coils and core under vibration, coolant flow, electric stresses, repeated temperature changes, etc., for the operating life of the machine. Preferably, these paths will be heat conductors as well.

Claims

1. A core and coil structure for a dynamoelectric machine comprising a stack of laminations formed with slots for receiving sides of coils;

and a winding of coils having sides disposed in said slots and end turns projecting from the core stack, each one of said coil sides having at least one conductor strand encased in a hard, unyielding jacket of insulating materials and the jacket of insulating materials covered by a hard, unyielding, semiconducting armor jacket;

variations in the laminations and the surface of said armor jacket defining voids between the armor jacket and the slot wall;

the improved means for conducting electric charge from said armor jacket to said core stack comprising a pressure deformable, semiconducting material located continuously between said armor jacket and said slot wall, said semi-conducting material being deformed by pressure into said voids and having an electrical resistance low enough to conduct electric charge from said armor jacket to said core stack and high enough to avoid significant eddy current flow between core laminations; and

, wherein said semi-conducting material is a room temperature vulcanizing silicone resin filled with fine particle graphite and/or lamp black in an amount that gives the filled resin an electrical resistance within an approximate range of 1000 to 80,000 ohms per square.

2. The structure defined in claim 1, wherein said semiconducting material is in the form of at least one thin layer bonded to said armor jacket.

3. The structure defined in claim 1, wherein said semiconducting material is in the form of generally triangular shaped strips bonded to said armor jacket.

4. The structure defined in claim 1, wherein said semiconducting material is in the form of discrete humps bonded to said armor jacket.