Electric machine cooling of stator with tube

1. A system comprising:

an electric machine including:

a stator comprising one or more windings;

a rotor comprising a plurality of permanent magnets configured to reduce induced currents in the rotor and cause a majority of heat generated by the electric machine via energy conversion losses to be localized to the windings of the stator;

a proximal bearing housed within a proximal bearing volume disposed along a proximal half of the rotor;

a proximal bearing volume fluid inlet and a proximal bearing volume fluid outlet;

a distal bearing housed within a distal bearing volume separate from the proximal bearing volume and disposed along a distal half of the rotor;

a distal bearing volume fluid inlet and a distal bearing volume fluid outlet;

a cooling system configured to supply, from a cooling fluid tank, a cooling fluid to cool the electric machine;

a stator tube configured to contain the cooling fluid within a stator portion of the electric machine and prevent the cooling fluid from contacting the rotor, the stator tube including a stator fluid inlet and a stator fluid outlet;

an engine; and

a chip detector fluidically coupled to the proximal bearing volume fluid outlet and the distal bearing volume fluid outlet and configured to receive the cooling fluid from the proximal bearing volume and the distal bearing volume, wherein cooling fluid exiting the stator fluid outlet does not flow through the chip detector before returning to the cooling fluid tank;

wherein the cooling system comprises a cooling circuit that includes both the engine and the electric machine, and wherein the cooling system is configured to supply the cooling fluid to the engine to cool the engine,

wherein the cooling system is configured to supply, from the cooling fluid tank, the cooling fluid to:

the proximal bearing volume via the proximal bearing volume fluid inlet,

to the distal bearing volume via the distal bearing volume fluid inlet, and

to the stator tube via the stator fluid inlet,

wherein the cooling fluid is configured to cool and lubricate the proximal and distal bearings, wherein the rotor is configured to transfer heat through the proximal and distal bearings to the cooling fluid.

2. The system of claim 1 , wherein the electric machine comprises a generator, wherein the rotor of the generator is coupled to an output shaft of the engine and is configured to be driven by the engine.

3. The system of claim 2 , wherein the engine comprises a gas turbine engine.

4. The system of claim 1 , wherein the cooling fluid is configured to cool and lubricate the proximal bearing or the distal bearing.

5. The system of claim 1 , wherein the cooling system comprises:

a pump in fluid communication with the fluid tank and configured to move fluid within the cooling circuit to the engine and the electric machine; and

a heat exchanger configured to receive the cooling fluid from any of the electric machine, the engine, and the pump, wherein the heat exchanger is configured to remove heat from the cooling fluid,

wherein the cooling fluid tank is configured to store the cooling fluid.

6. The system of claim 1 , wherein the cooling fluid comprises oil or water.

7. The system of claim 1 , wherein the cooling circuit is configured to supply the same cooling fluid to the engine and the electric machine.

8. A method of cooling an electric machine, the method comprising:

supplying, by a cooling system, a cooling fluid to flood a stator portion of the electric machine with the cooling fluid, wherein the electric machine comprises a stator tube configured to contain the cooling fluid within the stator portion of the electric machine and prevent the cooling fluid from contacting a rotor of the electric machine, wherein the stator portion comprises one or more windings, wherein the rotor comprises a plurality of permanent magnets configured to reduce induced currents in the rotor and cause a majority of heat generated by the electric machine via energy conversion losses to be localized to the windings of the stator portion;

supplying, by the cooling system and via a proximal bearing volume inlet, the cooling fluid to a proximal bearing volume comprising a proximal bearing disposed along a proximal half of the rotor and in contact with a portion of the rotor;

supplying, by the cooling system and via a distal bearing volume inlet, the cooling fluid to a distal bearing volume comprising a distal bearing disposed along a distal half of the rotor and in contact with a portion of the rotor;

receiving, by a chip detector, the cooling fluid from at least one of the proximal bearing volume or the distal bearing volume, wherein the cooling fluid exiting the stator portion is not received by the chip detector before returning to a cooling fluid tank configured to store the cooling fluid; and

analyzing, by the chip detector, the cooling fluid for chips.

9. The method of claim 8 , wherein the cooling fluid is configured to both cool and lubricate the proximal bearing and the distal bearing.

10. The method of claim 8 , further comprising:

supplying, by the cooling system, the cooling fluid to an engine mechanically connected to the electric machine via a shaft.

11. The method of claim 8 , wherein the cooling fluid comprises an oil or water.

12. A system comprising:

an electric machine comprising:

a stator comprising one or more windings;

a stator tube comprising a stator fluid inlet and a stator fluid outlet;

a rotor comprising a plurality of permanent magnets configured to reduce induced currents in the rotor and cause a majority of heat generated by the electric machine via energy conversion losses to be localized to the windings of the stator;

a proximal bearing housed within a proximal bearing volume disposed along a proximal half of the rotor;

a proximal bearing volume fluid inlet and a proximal bearing volume fluid outlet;

a distal bearing housed within a distal bearing volume separate from the proximal bearing volume and disposed along a distal half of the rotor;

a distal bearing volume fluid inlet and a distal bearing volume fluid outlet;

a gas turbine engine comprising a shaft coupled to the rotor of the electric machine;

a cooling system comprising:

a cooling circuit configured to supply cooling fluid, from a cooling fluid tank configured to store the cooling fluid, to the gas turbine engine, the stator tube via the stator fluid inlet, the proximal bearing volume via the proximal bearing volume fluid inlet, and the distal bearing volume via the distal bearing volume fluid inlet, wherein the stator tube is configured to contain the cooling fluid within a stator portion of the electric machine and prevent the cooling fluid from contacting the rotor; and

a chip detector fluidically coupled to the proximal bearing volume fluid outlet and distal bearing volume fluid outlet and configured to receive the cooling fluid from the proximal bearing volume and the distal bearing volume, wherein cooling fluid exiting the stator fluid outlet does not flow through the chip detector before returning to the cooling fluid tank.

13. The system of claim 12 , wherein the cooling fluid comprises an oil or water.

14. The system of claim 12 , wherein the cooling circuit is configured to supply the same cooling fluid to the gas turbine engine and the electric machine.

15. The system of claim 12 , wherein the cooling system further comprises:

a pump in fluid communication with the cooling fluid tank and configured to move fluid within the cooling circuit to the gas turbine engine and the electric machine; and

a heat exchanger configured to receive the cooling fluid from any of the electric machine, the gas turbine engine, and the pump, wherein the heat exchanger is configured to remove heat from the cooling fluid.

16. The system of claim 12 , wherein the rotor of the electric machine is coupled to an output shaft of the gas turbine engine and is configured to be driven by the gas turbine engine.