INSULATED BAR DYNAMOELECTRIC MACHINE AND METHOD OF FORMING

• US 3,659,129 A
• Filed: 09/15/1970
• Issued: 04/25/1972
• Est. Priority Date: 09/15/1970
• Status: Expired due to Term

• Current Assignee: Thomas P. Pettersen
• Original Assignee: Thomas P. Pettersen
• Inventors: Pettersen, Thomas P.
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Budd, Mark O.
• Application Number:
  US05/072,461
• Time in Patent Office: 588 Days
• Field of Search: 310/211,216-218,261,265,270 336/210
• US Class Current: 310/216.017
• CPC Class Codes: H02K 17/16 having rotors with internally short-circuited windings, e.g. cage rotors

Abstract

Rotor bars of a high starting torque squirrel cage motor are insulated from the sheet metal laminations forming the rotor by disposing insulating laminations at spaced apart locations along the rotor axis. The insulating laminations are pre-slit in registration with the slots of the juxtaposed sheet metal laminations and as the rotor bars are driven through the sheet metal laminations, the leaves of the pre-slit insulating laminations are folded back by the advancing bars to electrically insulate the rotor bars from the sheet metal laminations.

Claims

1. A dynamoelectric machine comprising a first magnetizable member composed of a plurality of juxtaposed sheet metal laminations disposed in axial alignment to form a substantially cylindrical surface, a plurality of axially extending slots circumferentially spaced about said first magnetizable member and opening into said cylindrical surface, conductor bars situated within said axially extended slots of said magnetizable members, laminations of an electrically insulating material juxtaposed with the sheet metal laminations situated at axially opposite ends of said first magnetizable member, said insulating laminations having slit sections registered with the slots of said magnetizable member, said slit sections of said insulating laminations being folded back to overlap at least one edge of the slot in the juxtaposed sheet metal lamination to electrically insulate the conductor bar from the juxtaposed sheet metal laminations, and a second magnetizable member forming a cylindrical surface in a concentric attitude relative to the cylindrical surface of said first magnetizable member, said second magnetizable member being susceptible to rotary motion relative to said first magnetizable member.

2. A dynamoelectric machine according to claim 1 wherein said insulating lamination is characterized by a slit section in axial alignment with each slot in said juxtaposed sheet metal lamination, said insulating lamination having a geometric configuration otherwise identical to the geometrical configuration of said juxtaposed sheet metal laminations.

3. A dynamoelectric machine according to claim 1 wherein a plurality of said insulating laminations are disposed at approximately equally spaced intervals along the axis of said first magnetic member.

4. A dynamoelectric machine according to claim 3 wherein the portions of said slit sections overlapping said juxtaposed sheet metal laminations extend over an axial span approximately equal to the distance between insulating laminations.

5. A dynamoelectric machine comprising:

I. A rotor characterized by a. a plurality of juxtaposed sheet metal laminations disposed in axial alignment along a central shaft to form a substantially cylindrical member, said laminations having punched apertures in registration to form axially extending slots through said cylindrical member, b. conductor bars extending through said slots and protruding axially outwardly from at least one end of said cylindrical member, and c. conductive means interconnecting the respective ends of said conductor bars;

II. a stator circumferentially disposed about said sheet metal laminations forming said rotor, and III. a support wheel of punched sheet metal laminations substantially identical to the sheet metal laminations forming said rotor axially mounted upon said shaft at a location rEmote from said rotor laminations, said support wheel being disposed along said shaft at a location such that the protruding ends of said conductor bars extend through the punched apertures of said magnetic laminations forming said support wheel.

6. A dynamoelectric machine according to claim 5 further including insulating laminations disposed adjacent said sheet metal laminations at opposite ends of said rotor, said insulating laminations having pre-slit sections folded back to overlap the edges of the sheet metal laminations juxtaposed therewith to electrically insulate said conductor bars from said sheet metal laminations.

7. A dynamoelectric machine according to claim 6 further including at least one insulating lamination juxtaposed with said sheet metal laminations forming said support wheel and disposed intermediate the sheet metal laminations of said support wheel and said rotor, said insulating lamination having pre-slit sections in registration with the punched apertures of said sheet metal laminations of said support wheel to insulate said conductor bars from said support wheel.

8. A rotor for a dynamoelectric machine comprising a plurality of sheet metal laminations juxtaposed in axial alignment to form a substantially cylindrical surface, said rotor having a plurality of circumferentially disposed slots spaced along the periphery of said member insulating laminations interspersed between said juxtaposed sheet metal laminations to form a plurality of groups of sheet metal laminations separated by at least one insulating lamination, said insulating laminations being slit at locations in registration with the circumferentially disposed slots of said sheet metal laminations to provide leaves within said insulating laminations, said leaves being folded back at a 90* angle relative to the plane of said insulating laminations to overlie the edges of the slot in the adjacent sheet metal laminations, rotor bars extending axially through said slots, said rotor bars contacting said folded back leaves of said insulating laminations and being spaced from said sheet metal laminations by the leaves of said insulating laminations overlying said adjacent slots edges, and means electrically interconnecting the respective ends of said rotor bars.