Starter motor-alternator apparatus

• US 4,219,739 A
• Filed: 04/27/1978
• Issued: 08/26/1980
• Est. Priority Date: 04/27/1978
• Status: Expired due to Term

• Current Assignee: Lear AVIA Corporation
• Original Assignee: Lear AVIA Corporation
• Inventors: Greenwell, Jack E.
• Primary Examiner(s): Hickey, Robert J.
• Application Number:
  US05/900,421
• Time in Patent Office: 852 Days
• Field of Search: 322/29, 322/32, 322/46, 290/32, 290/38, 290/46, 310/113, 310/240
• US Class Current: 290/46
• CPC Class Codes: F02N 11/04 the motors being associated with current generators
• CPC Class Codes: H02K 23/52 Motors acting also as generators, e.g. starting motors used as generators for ignition or lighting

Abstract

A starter-motor, and alternator-generator apparatus for an internal combustion or gas turbine engine wherein the major electro-magnetic circuit of the apparatus is utilized for both the starting and generating functions is disclosed. The rotor may have two windings on it, a main rotor winding that acts as both a starter armature winding and an alternator field winding, and a small exciter armature winding. For slip ring machines the exciter is eliminated. The main rotor winding is wound in progressive simplex lap. The exiter armature or slip rings are connected to this winding at the equalizer connections through a rectifier and automatically activated switch circuit. During starter-motor operation, the main rotor winding is connected in series with its starter field winding through a commutator in a conventional series connected DC machine, and the exciter-armature winding or slip rings are disconnected from the main rotor winding. During alternator-generator operation, the brushes are lifted off the commutator and the exciter-armature winding or slip rings are connected to the main rotor winding.

Claims

1. An electric machine having a rotor and stator portion and adapted to be driven by DC to produce torque for starting an engine, and when driven by such engine, to produce an AC electric output, said machine comprising:

a main rotor winding;

a main stator winding;

a heavy current commutation system including a commutator and brushes connecting said main rotor winding and said main stator winding in series for the production of torque to start said engine;

an exciter armature winding located on said rotor portion for joint rotation with said main rotor winding;

an exciter field winding on said stator portion coacting with said exciter armature winding;

a controlled rectifier set connected between the exciter-armature winding and the main rotor winding for feeding DC from AC generated by said exciter-armature winding to said main rotor winding; and

an automatically activated gate switching means connected between said controlled rectifier set and said main rotor winding, said switch means being open when said machine is driven by DC to produce torque and closed when driven by said engine to produce an AC electric output.

2. The electric machine of claim 1 wherein said main rotor winding is wound as a progressive simplex lap.

3. The electric machine of claim 1 wherein said main stator winding is a three-leg star, only one leg of said star winding being connected in series with said main stator winding by said current commutator system.

4. The electric machine of claim 1 further comprising an automatic brush-lifting mechanism which lifts the brushes out of contact with the commutator when a starting operation has been completed.

5. The electric machine of claim 1 wherein the exciter armature winding, including said controlled rectifier set is connected to two points on said main rotor winding that are 360 electrical degrees apart.

6. The electrical machine of claim 1 wherein said automatically activated switch means responds to current flow in said exciter armature winding to close, and the lack of current flow therein to open.

7. The electrical machine of claim 1 further comprising means for rectifying the AC electric output of said main stator winding to DC.

8. An electric machine having a rotor and a stator portion and adapted to be driven by DC to produce torque for starting an engine, and when driven by such engine for producing an AC electric output, said machine comprising:

a rotor winding;

a stator winding;

a heavy current commutation system, including a commutator and brushes connecting said rotor winding and said stator winding in series for the production of torque to start said engine;

means for generating DC;

means for lifting the brushes out of contact with the commutator when said rotor portion is driven by said engine; and

means for automatically feeding DC from said DC generating means to said rotor winding when said rotor portion is driven by said engine;

whereby said rotor winding acts as a motor armature winding during starting operations and as an alternator field winding during generating operations.

9. An electric machine having a rotor and a stator portion and adapted to be driven by DC to produce torque for starting an engine, and when driven by such engine for producing an AC electric output, said machine comprising:

a rotor winding;

a stator winding;

means for connecting said stator winding and said rotor winding in series for the production of torque to start said engine;

means for generating DC;

means for disconnecting said stator winding and said rotor winding when said engine has started and said rotor portion is driven by said engine; and

means for automatically exciting said rotor winding with DC from said DC generating means when said rotor portion is driven by said engine.

10. The electric machine of claim 9 wherein said connecting and disconnecting means, and said exciting means, are automatically activated.