Alternating current generator

• US 4,882,515 A
• Filed: 10/28/1988
• Issued: 11/21/1989
• Est. Priority Date: 06/03/1988
• Status: Expired due to Fees

• Current Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Radomski, Thomas A.
• Primary Examiner(s): Salce, Patrick R.
• Assistant Examiner(s): Jones, Judson H.
• Application Number:
  US07/263,850
• Time in Patent Office: 389 Days
• Field of Search: 310/156, 310/168, 310/263, 310/194, 310/261
• US Class Current: 310/263
• CPC Class Codes: H02K 16/02 Machines with one stator and two or more rotors
• CPC Class Codes: H02K 21/044 Rotor of the claw pole type
• CPC Class Codes: H02K 21/14 with magnets rotating within the armatures

Abstract

An alternating current generator for supplying the electrical loads on a motor vehicle. The generator has a stator core that carries a three-phase stator or output winding. The rotor of the generator has two claw pole members that are so oriented that the fingers of the pole members are aligned. Disposed between the two pole members is a third pole member having projections disposed between the aligned fingers of the claw pole members. The rotor has two field coils which are so arranged and energized that the magnetic polarity of the two claw pole members is the same and opposite the magnetic polarity of the third pole member. One of the field coils can be replaced by a permanent magnet and when this is done the generator is provided with a magnetic circuit that can divert permanent magnet flux away from the stator core. Flux diversion is controlled by supplying unidirectional current to the field winding under the control of a voltage regulator.

Claims

1. A voltage regulated alternating current generator comprising, frame means, a stator supported by said frame means comprising a stator core formed of magnetic material that has slots, an output winding carried by said stator core including conductors disposed within said slots, a rotor supported for rotation by said frame means disposed within said stator core, said rotor comprising a shaft, first and second claw pole members formed of magnetic material carried by said shaft, each pole member having a plurality of circumferentially spaced and axially extending pole fingers, the number of fingers of said first pole member being equal to the number of fingers of said second pole member, said first and second pole members being so oriented on said shaft that the pole fingers of said first and second pole members are aligned with each other, said first and second pole fingers being connected in such a manner that they magnetically connect said first and second pole members through the magnetic material of said first and second pole fingers, the outer periphery of the pole fingers of said first and second pole members being aligned with portions of the inner surface of said stator core, a third pole member means formed of magnetic material carried by said shaft having circumferentially spaced pole projections, said third pole means having disk portion means disposed between said first and second pole members, the projections of said third pole member means being disposed between the fingers of said first and second pole members, a field coil located between said first pole member and said third pole member means, a permanent magnet having opposed end faces of opposite magnetic polarity located between said third pole member means and said second pole member, said field coil being so wound and electrically connected and the end faces of said permanent magnet being so magnetically poled that when said field coil is energized with direct current the pole fingers of said first and second pole members have the same magnetic polarity and the pole projections of said third pole member means has an opposite magnetic polarity whereby the fluxes developed respectively by said field coil and permanent magnet that traverses said stator core is additive, means including said disk portion means and said connected first and second pole fingers defining a closed magnetic circuit formed entirely of magnetic material that magnetically connects said opposed end faces of said permanent magnet, said magnetic circuit shunting the air gap between said rotor and stator core whereby the flux developed by said permanent magnet is diverted from said air gap by said magnetic circuit and only leakage flux developed by said permanent magnet traverses said stator core when said field coil is not energized, the magneto-motive-force developed by said field coil when energized causing the flux developed by said permanent magnet that is diverted through said magnetic circuit to be reduced whereby flux developed by said permanent magnet that traverses the air gap between said rotor and stator increases, and voltage regulating means for maintaining the output voltage of said generator at a desired regulated value, said regulating means applying direct field current to said field winding in only one direction through said field winding, said regulating means including means for varying the magnitude of said direct field current as an inverse function of the output voltage of said generator, the amount of flux developed by said permanent magnet that is diverted through said magnetic circuit decreasing as said field current increases and increasing as said field current decreases.

2. The alternating current generator according to claim 1 where said third pole member means is comprised of a pair of pole members having engaged disk portions, each pole member having pole projections that extend in opposite directions.

3. The alternating current generator according to claim 1 where the connection between said first and second pole fingers is accomplished by engaged end faces of said first and second pole fingers.

4. The alternating current generator according to claim 1 where said first and second pole fingers are defined by a one-piece part formed of magnetic material that is connected between said first and second pole members.