Internally air cooled exciter-current lead-through bolt interconnecting rotor shaft-enclosed lead-in conductor bar and terminal conductor bar leading to rotor winding

• US 4,074,155 A
• Filed: 12/30/1975
• Issued: 02/14/1978
• Est. Priority Date: 01/16/1975
• Status: Expired due to Term

• Current Assignee: BBC Brown Boveri & Company Limited (ABB Limited)
• Original Assignee: BBC Brown Boveri & Company Limited (ABB Limited)
• Inventors: Haditsch, Werner, Toplak, Ernst, Rutz, Hansruedi
• Primary Examiner(s): Skudy, R.
• Application Number:
  US05/645,322
• Time in Patent Office: 777 Days
• Field of Search: 310/61, 310/59, 310/58, 310/52, 310/60, 310/64, 310/65, 310/53, 310/57, 310/71, 310/165, 310/231, 310/261, 310/232, 310/68, 310/680, 310/112-114
• US Class Current: 310/59
• CPC Class Codes: H02K 3/51 applicable to rotors only
• CPC Class Codes: H02K 9/00 Arrangements for cooling or ventilating channels or ducts in parts of the magnetic circuit H02K1/20, H02K1/32; channels or ducts in or between conductors H02K3/22, H02K3/24

Abstract

An exciter-current lead-through bolt which is passed through a radial bore in the rotor shaft of a dynamo-electric machine, especially a turbo-generator, and screwed into an exciter-current lead-in conductor bar which lies in a longitudinally extending bore within the shaft. The radially outer part of the lead-through bolt is mechanically and electrically connected with a terminal conductor bar leading to the exciter winding located on the rotor. The lead-through bolt preferably made of steel because of its high mechanical strength is cooled internally by means of a forced air circulation system including a tube inserted in a longitudinal bore through the bolt, the diameter of the bore being greater than the external diameter of the tube in order to provide an annular space therebetween for flow of air from an air inlet port outside of the shaft radially inward to the end of the tube adjacent the inner end of the bolt, then into the tube and radially outward therethrough to an air discharge port also located outside of the rotor shaft and at a radial distance greater than the air inlet port.

Claims

1. The combination with a rotor shaft of a dynamo-electric machine including a longitudinal bore containing an insulated exciter-current lead-in conductor bar and a radial bore extending from said longitudinal bore to the surface of the shaft, of a radially extending exciter-current lead-through bolt mounted in and extending through said radial bore, means securing the radially inner end of said bolt in said lead-in conductor bar, means securing the radially outer part to a terminal conductor bar leading to an exciter winding located on said rotor, and means for cooling said bolt comprising a ventilating tube disposed within a longitudinal bore extending through said bolt, said tube being smaller than the bolt bore to establish a gap between said tube and the wall of the bore, and a ventilating hood mounting the outer end of said ventilating tube and which is mounted atop the radially outer end of said bolt in the ambient air, said hood including a first port extending through the wall thereof placing said gap in communication with the ambient air and a second port placing the outer end of said ventilating tube in communication with the amient air, said ports establishing an air inlet and air outlet respectively thereby to establish a circulating flow path for ambient cooling air in one radial direction through said gap and in the opposite direction through said ventilating tube.

2. The invention as defined in claim 1 wherein said first port through said ventilating hood is located at a radial distance smaller than said second port whereby the flow of ambient cooling air is radially inward through said gap and thence radially outward through said ventilating tube.

3. The invention as defined in claim 2 wherein said first port on said hood faces in the direction of rotation of said rotor shaft and said second port faces in the opposite direction.

4. The invention as defined in claim 1 and which further includes an externally threaded nut surrounding said bolt, said nut being screwed into a threaded portion of said radially extending shaft bore and applying a radially inward directed pressure against a collar formed on said bolt by a rounded transition from the bolt surface with an insulation member inserted therebetween.