Electrical machine

1. An electrical machine comprising:

a stator including a plurality of three or more electrical phases;

a rotor having a plurality of magnets, each electrical phase comprising at least one coil and power electronics;

a power supply for supplying power to each of the power electronics;

electrical connections connecting each phase to at least two other phases while bypassing the power supply;

means to detect an electrical short circuit in at least one of the coils to determine a faulted turn of the at least one coil, and

means to supply an electrical current to the at least one of the coils having a faulted turn when an electrical short circuit is detected in the at least one of the coils, wherein:

the means to supply the electrical current to the at least one of the coils having a faulted turn comprises electrical connections between at least one un-faulted electrical phase of the electrical machine and the phase containing the at least one of the coils having a faulted turn, and

the at least one un-faulted electrical phase of the electrical maching is arranged to supply the electrical current to the electrical phase containing the at least one of the coils having a faulted turn.

2. An electrical machine as claimed in claim 1 wherein the power electronics of the at least one un-faulted electrical phase is arranged to supply the electrical current from the at least one un-faulted electrical phase to the power electronics of the electrical phase having the at least one of the coils having a faulted turn.

3. An electrical machine as claimed in claim 1 wherein two or more of the un-faulted electrical phases of the electrical machine are arranged to supply the electrical current to the electrical phase containing the at least one of the coils having a faulted turn.

4. An electrical machine as claimed in claim 3 wherein all of the un-faulted electrical phases of the electrical machine are arranged to supply the electrical current to the electrical phase containing the at least one of the coils having a faulted turn.

5. An electrical machine as claimed in claim 2 wherein the power electronics of the at least one un-faulted phase of the electrical machine is arranged to store the electrical current in the power electronics before the power electronics of the at least one un-faulted electrical phase is arranged to supply the electrical current from the at least one un-faulted electrical phase to the power electronics of the phase having the at least one of the coils having a faulted turn.

6. An electrical machine as claimed in claim 1 wherein the magnets are permanent magnets.

7. An electrical machine as claimed in claim 1 wherein the electrical machine is an electrical motor, an electrical generator or a combined electrical motor and electrical generator.

8. An electrical machine as claimed in claim 7 wherein the electrical machine is an electrical starter/electrical generator.

9. An electrical machine as claimed in claim 1 wherein the electrical machine is a fault tolerant electrical machine.

10. An electrical machine as claimed in claim 1 wherein the electrical machine is an electrical machine of a gas turbine engine, an aircraft or a ship.

11. An electrical machine as claimed in claim 1 wherein the electrical machine is connected to a busbar.

12. An electrical machine as claimed in claim 11 wherein the means to supply the electrical current to the at least one of the coils having a faulted turn comprises means to detect a short circuit or fault in the busbar and the means to detect a short circuit or fault in the busbar is arranged to allow the at least one un-faulted phase of the electrical machine to supply the electrical current to the at least one of the coils having a faulted turn if there is a short circuit or fault in the busbar.

13. An electrical machine as claimed in claim 12 wherein the electrical machine is connected to the busbar via a circuit breaker.

14. An electrical machine as claimed in claim 13 wherein the means to supply the electrical current to the at least one of the coils having a faulted turn comprises means to detect a disturbance in the voltage of the busbar and the means to detect a disturbance in the voltage in the busbar is arranged to open the circuit breaker if there is a disturbance in the voltage in the busbar to allow the at least one un-faulted phase of the electrical machine to supply the electrical current to the at least one of the coils having a faulted turn.

15. An electrical machine comprising:

a stator including a plurality three or more electrical phases;

a rotor having a plurality of magnets, the magnets are permanent magnets, each electrical phase comprising at least one coil and power electronics;

a power supply for supplying power to each of the power electronics;

electrical connections connecting each phase to at least two other phases while bypassing the power supply;

a detector to detect an electrical short circuit in at least one of the coils to determine a faulted turn of the at least one coil; and

an electrical supply to supply an electrical current to the at least one of the coils having a faulted turn when an electrical short circuit is detected in the at least one of the coils, wherein:

the electrical supply to supply the electrical current to the at least one of the coils having a faulted turn comprises electrical connections between at least one un-faulted electrical phase of the electrical machine and the phase containing the at least one of the coils having a faulted turn, and

the at least one un-faulted electrical phase of the electrical machine is arranged to supply the electrical current to the electrical phase containing the at least one of the coils having a faulted turn.

16. An electrical machine comprising:

a stator including a plurality of electrical phases and a rotor having a plurality of magnets, each electrical phase comprising:

at least one coil and power electronics,

means to detect an electrical short circuit in at least one of the coils to determine a faulted turn of the at least one coil, and

means to supply an electrical current to the at least one of the coils having a faulted turn when an electrical short circuit is detected in the at least one of the coils,

the electrical machine is connected to a busbar wherein the means to supply the electrical current to the at least one of the coils having a faulted turn comprises at least one un-faulted electrical phase of the electrical machine, the power electronics of the at least one un-faulted electrical phase is arranged to supply the electrical current from the at least one un-faulted electrical phase to the power electronics of the electrical phase having the at least one of the coils having a faulted turn via electrical connections,

the means to supply the electrical current to the at least one of the coils having a faulted turn comprises means to detect a short circuit or fault in the busbar and the means to detect a short circuit or fault in the busbar is arranged to allow the at least one un-faulted phase of the electrical machine to supply the electrical current to the at least one of the coils having a faulted turn if there is a short circuit or fault in the busbar.