ROTOR BASED AIR GAP HEATING FOR AIR DRIVEN TURBINE

• US 20120056601A1
• Filed: 09/03/2010
• Published: 03/08/2012
• Est. Priority Date: 09/03/2010
• Status: Active Grant

• Current Assignee: Hamilton Sundstrand Corporation (Rtx Corporation)
• Original Assignee: Hamilton Sundstrand Corporation (Rtx Corporation)
• Inventors: Spierling, Todd A.
• Granted Patent: US 8,575,900 B2
• Time in Patent Office: Days
• 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:

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

a deicing circuit operable during a time when the main generator rotor is not being rotated by the 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 exciter armature windings that is provided to the main generator windings for producing resistance heating around the main generator rotor windings 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 first exciter output current is rectified into direct current before being conducted through the main rotor field windings.

7. The generator apparatus of claim 1, further comprising a generator control unit for regulating the alternating input current for 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 operable during a time when the main generator rotor is being rotated by the 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 a turbine and a hub rotatably connected to a turbine shaft;

a self-deicing generator assembly including a deicing circuit operable during a time when a generator shaft is not rotating, the deicing circuit including a first power source for energizing a plurality of exciter field windings with an alternating input current to induce an exciter output current in a plurality of exciter armature windings that is provided to a plurality of main generator rotor windings disposed proximate an air gap between a main generator rotor and a main generator stator, the current provided to cause resistance heating around the main generator 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 exciter output current is rectified into direct current before energizing the main rotor field windings.

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

supplying an alternating current to 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 exciter output current to a plurality of substantially stationary main rotor windings disposed proximate the air gap, to cause resistance heating that heats the air gap to a temperature sufficient to melt or sublimate a quantity of ice.

16. The method of claim 15, wherein the alternating current is supplied by 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 from generated from at least one of:

a main aircraft generator and an auxiliary power unit.

18. The method of claim 15, wherein the source of alternating current is 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

regulating the alternating 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 regulates the alternating current supplied to the plurality of exciter field windings.