Rotor based air gap heating for air driven turbine

• US 8,575,900 B2
• Filed: 09/03/2010
• Issued: 11/05/2013
• Est. Priority Date: 09/03/2010
• Status: Expired due to Fees

• Current Assignee: Hamilton Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Hamilton Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Spierling, Todd A.
• Primary Examiner(s): Patel, Tulsidas C
• Assistant Examiner(s): NGUYEN, VIET P
• Application Number:
  US12/875,475
• Publication Number:
  US 20120056601A1
• Time in Patent Office: 1,159 Days
• Field of Search: 322/33, 322/34, 322/59, 322/60, 322/61, 219/213, 219/494, 219/497, 219/507, 219202-203, 340/962, 340580-583, 244/134.R, 244/134.A, 244/134.B, 244/134.C, 244/134.D
• US Class Current: 322/34
• CPC Class Codes: B64D 15/12 by electric heating electric heating elements in general H05B
• CPC Class Codes: B64D 41/007 Ram air turbines
• CPC Class Codes: F05B 2220/31 in ram-air turbines ("RATS")
• CPC Class Codes: H02P 2101/15 for wind-driven turbines
• CPC Class Codes: H02P 2101/30 for aircraft
• CPC Class Codes: H02P 29/62 for raising the temperature of the motor
• CPC Class Codes: H02P 9/302 Brushless excitation

Abstract

A generator apparatus comprises a deicing circuit. The deicing circuit is operable during a time when a main generator rotor is not being rotated by a generator shaft. The deicing circuit includes a first power source for energizing a plurality of exciter field windings with alternating input current to induce an exciter output current in a plurality of exciter armature windings. The exciter output current is provided to main generator rotor windings for producing resistance heating around an air gap separating the main generator rotor from a main generator stator.

Claims

1. A self-deicing generator apparatus comprising:

an air-driven turbine including a turbine hub;

a generator shaft rotatably coupled to the turbine hub;

a stationary generator assembly including a main generator stator having a plurality of main generator stator windings, and an exciter stator having a plurality of exciter field windings;

a rotatable assembly including a main generator rotor and an exciter rotor mounted to the generator shaft, the exciter rotor having a plurality of exciter armature windings disposed coaxially adjacent to the plurality of exciter field windings, and the main generator rotor having a plurality of main rotor windings disposed coaxially adjacent to the plurality of main stator windings, the main generator rotor and the main generator stator separated by an air gap; and

a deicing circuit operable during a time when the rotatable assembly is not being rotated by the generator shaft, the deicing circuit including a first power source for selectively energizing the plurality of exciter field windings with an alternating input current, the alternating input current inducing an exciter output current in the exciter armature windings that is provided to energize the main rotor windings for producing resistance heating around the main generator rotor to melt or sublimate a quantity of ice accumulated in the air gap.

2. The generator apparatus of claim 1, wherein the first power source is an aircraft electrical power distribution system that provides three-phase alternating current.

3. The generator apparatus of claim 2, wherein the aircraft electrical power distribution system is configured to receive power from at least one of:

a main aircraft electrical generator, and an auxiliary power unit.

4. The generator apparatus of claim 2, wherein the aircraft electrical power distribution system receives power from an inverter electrically connected to a direct current power source.

5. The generator apparatus of claim 1, wherein the first power source is an aircraft electrical distribution system operating with direct current, and the direct current is converted into three-phase alternating current by an inverter.

6. The generator apparatus of claim 1, wherein the induced exciter output current comprises three-phase alternating output current rectified into direct current before energizing the main rotor windings.

7. The generator apparatus of claim 1, further comprising a generator control unit for regulating the alternating input current selectively energizing the plurality of exciter field windings.

8. The generator apparatus of claim 1, further comprising:

a second power source for energizing the plurality of exciter field windings as part of a generating circuit, the generating circuit operable during a time when the rotatable assembly is being rotated by the generator shaft.

9. The generator apparatus of claim 8, wherein the second power source is a permanent magnet generator.

10. The generator apparatus of claim 8, wherein current from the second power source is rectified before energizing the plurality of exciter field windings.

11. A turbine module comprising:

a turbine assembly including an air-driven turbine with a turbine hub, the turbine hub rotatably connected to a turbine shaft;

a generator shaft rotatably coupled to the turbine shaft;

a self-deicing generator assembly including a rotor assembly mounted to the generator shaft, and a stator assembly coaxially spaced from the rotor assembly by an air gap, the rotor assembly having a plurality of main rotor windings and a plurality of exciter armature windings, the stator assembly having a plurality of main stator windings disposed coaxially adjacent to the plurality of main rotor windings, and a plurality of exciter field windings spaced coaxially from the plurality of exciter armature windings; and

a deicing circuit operable during a time when the generator shaft is not being rotated by the turbine shaft, the deicing circuit including a first power source for energizing the plurality of exciter field windings with an alternating input current to induce an exciter output current in the plurality of exciter armature windings, the induced exciter output current from the exciter armature windings provided to energize the plurality of main rotor windings disposed proximate the air gap, the energized main rotor windings causing resistance heating around the main rotor windings to melt or sublimate a quantity of ice accumulated in the air gap.

12. The turbine module of claim 11, wherein the first power source is an aircraft electrical power distribution system for providing three-phase alternating current.

13. The turbine module of claim 12, wherein the aircraft electrical power distribution system receives power from at least one of:

a main aircraft electrical generator, and an auxiliary power unit.

14. The turbine module of claim 11, wherein the induced exciter output current comprises three-phase alternating output current rectified into direct current before energizing the main rotor windings.

15. A method for removing ice from an air gap of a generator assembly, the method comprising:

operating a deicing circuit during a time that a rotatable assembly is not being rotated by a generator shaft, the operating step including supplying an alternating input current from a first power source to selectively energize a plurality of exciter field windings to induce an exciter output current in a plurality of substantially stationary exciter armature windings coaxially adjacent to the plurality of exciter field windings; and

directing the induced exciter output current to energize a plurality of substantially stationary main rotor windings disposed proximate the air gap;

during the steps of supplying an alternating input current and directing the induced exciter output current, maintaining the energized rotor windings in a substantially stationary position to cause resistance heating that heats the air gap to a temperature sufficient to melt or sublimate a quantity of ice disposed therein.

16. The method of claim 15, wherein the first power source comprises an aircraft electrical distribution system operating with three-phase alternating current.

17. The method of claim 16, wherein the aircraft electrical distribution system receives power generated from at least one of:

a main aircraft generator and an auxiliary power unit.

18. The method of claim 15, wherein the first power source comprises an inverter electrically connected to an aircraft electrical distribution system operating with direct current.

19. The method of claim 15, further comprising the steps of:

periodically measuring the temperature in or proximate the air gap;

comparing the measured temperature to a predetermined temperature range; and

selectively regulating the alternating input current supplied to the plurality of exciter field windings to maintain the measured temperature within the predetermined temperature range.

20. The method of claim 19, wherein a generator control unit selectively regulates the alternating input current supplied to the plurality of exciter field windings.