Brushless exciter fault indicator system

• US 4,164,705 A
• Filed: 04/27/1976
• Issued: 08/14/1979
• Est. Priority Date: 04/27/1976
• Status: Expired due to Term

• Current Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Gorden, Dale I., Whitney, Eugene C.
• Primary Examiner(s): Rolinec, Rudolph V.
• Assistant Examiner(s): Karlsen, Ernest F.
• Application Number:
  US05/680,658
• Time in Patent Office: 1,204 Days
• Field of Search: 324/158 MG, 324/127, 324/158 D, 324/51, 318/490, 322/99, 310/68 R, 310/68 B, 310/68 C, 310/254, 310/259, 310/68 D, 340/645
• US Class Current: 324/765.01
• CPC Class Codes: G01R 31/343 in operation
• CPC Class Codes: H02H 7/065 against excitation faults

Abstract

A brushless excitation system for a synchronous dynamoelectric machine includes an alternating current exciter and a rotating rectifier assembly. In such a system, the alternating current exciter includes a salient pole stator field member and a polyphase armature rotor member. A sensing coil is disposed around at least one of the salient stator poles for developing an alternating electrical signal in response to changes in the magnetic flux wave linking the rotating armature member and the field coil of the salient stator pole member. Means connected to the sensing coil indicates variations in the alternating current signal which correspond with disturbances in the rotary electric circuit of the brushless exciter such as a line-to-line short circuit or a phase-to-phase short circuit in the armature winding, or shorted diodes or open fuses in the rotating rectifier assembly.

Claims

1. In a synchronous dynamoelectric machine with brushless excitation, the combination comprising:

a main machine rotor member having field coils connected together to form a main rotor field winding, an alternating current exciter having a stator field member and a plurality of salient stator poles thereon, stator field coils disposed on said salient poles and connected together to form a stator exciter field winding, an exciter armature member rotatable with said main rotor field winding and having an armature winding thereon, said exciter armature winding being coupled magnetically with said exciter stator field winding for developing an alternating current excitation signal within said armature winding, rectifier means interconnecting said exciter armature winding and said main rotor field winding to provide direct current excitation to said main rotor field winding, said rectifier means being rotatable with said armature, a sensing coil disposed around a selected one of said salient stator poles of said exciter for developing an alternating electrical signal in response to changes in the magnetic flux wave linking said rotating exciter armature member and the field coil of said selected salient pole, including changes due to faults in said armature winding and in said rectifier means, and means connected to said sensing coil to indicate variations in said alternating electrical signal.

2. A synchronous dynamoelectric machine as defined in claim 1, said exciter armature member including a cylindrical core having winding slots disposed about the circumference of said core, said armature winding including a plurality of coils constituting each phase of said winding, said coils being disposed in said core slots and being angularly displaced with respect to one another, said coils being electrically connected together in parallel within each phase of said armature winding, said rectifier means including a plurality of series connected diode and fuse pairs, at least one series connected diode-fuse pair being connected in series with each said parallel-connected phase coil.

3. In brushless exciter apparatus, the combination comprising:

a shaft, a rotatable armature member disposed on said shaft, said armature having an armature winding electrically connected with a rectifier assembly that is rotatable with said armature, a stator member with a plurality of salient poles that are concentrically disposed about and spaced apart from said armature, a stator field coil disposed on each said salient pole, said stator field coils being connected together to constitute a stator field winding;

a sensing coil disposed on a selected one of said salient stator poles for developing an alternating electrical signal in response to changes in the magnetic flux linking said armature winding with the field coil of said selected salient pole, including changes due to faults in said armature winding and in said rectifier assembly, said field coils each encircling one of said poles in a first plane parallel to the axis of said shaft, said sensing coil encircling said selected salient pole in a second plane parallel to said first plane and being located radially inward of the associated field coil relative to the axis of said shaft; and

means connected to said sensing coil to indicate variations in said alternating electrical signal.

4. The combination defined in claim 3, said indicating means comprising an oscilloscope having its sweep synchronized with the rotation of said armature.

5. The combination defined in claim 3, including a layer of electrical insulation disposed intermediate of said selected one of said salient field poles and the associated field coil, said sensing coil being disposed within said insulation.