Safe electrical machine

1. An electrical machine, comprising:

a rotor carrying a brake element and a release device;

an overload coupling configured to be actuated by a release of said brake element, said brake element being configured, upon being released, to emerge radially from said rotor into an air gap of said electrical machine.

2. The electrical machine according to claim 1 , wherein said release device is a binding band.

3. The electrical machine according to claim 1 , wherein said brake element is a permanent magnet or a soft magnetic element.

4. The electrical machine according to claim 1 , wherein an actuation is thermally induced.

5. The electrical machine according to claim 4 , wherein the actuation is triggered by a winding short-circuit.

6. A rail vehicle, comprising:

an electrical machine having a rotor, a stator and an air gap between said rotor and said stator;

a wheelset to be driven by said electrical machine, wherein the electrical machine is separable from the wheelset in the event of a fault in the electrical machine;

a brake element disposed to emerge from said rotor, on occasion of a fault, into said air gap of said electrical machine.

7. The rail vehicle according to claim 6 , which comprises a transmission between said wheelset and said electrical machine.

8. The rail vehicle according to claim 6 , wherein said electrical machine comprises:

a rotor carrying a brake element and a release device; and

an overload coupling configured to be actuated by a release of said brake element, said brake element being configured, upon being released, to emerge from said rotor.

9. A method for braking a rotor of an electrical machine for driving a vehicle, the method comprising:

in the event of a fault in a drive train of the vehicle, causing a brake element carried on a rotor of the electrical machine to emerge radially from the rotor and to thereby generate an overload torque by the electrical machine.

10. The method according to claim 9 , wherein the electrical machine drives a rail vehicle or a road vehicle.

11. The method according to claim 9 , which comprises stopping the rotor by the overload torque.

12. The method according to claim 9 , which comprises actuating an overload coupling with the overload torque.

13. The method according to claim 9 , wherein the fault in the drive train is a winding short-circuit in a stator of the electrical machine.

14. The method according to claim 9 , which comprises holding the brake element in or on the rotor with a binding band during fault-free operation and, for generating the overload torque in the event of the fault, causing the binding band to become delaminated.

15. The method according to claim 9 , which comprises detecting a winding short-circuit in the stator and actuating the overload coupling by employing a mechanical chain of action.

16. The method according to claim 9 , which comprises driving the vehicle with an electrical machine that includes:

a rotor carrying a brake element and a release device; and

an overload coupling configured to be actuated by a release of the brake element, the brake element being configured, upon being released, to emerge from the rotor.

17. The method according to claim 9 , wherein the vehicle is a rail vehicle that includes:

an electrical machine having a rotor, a stator and an air gap between the rotor and the stator;

a wheelset to be driven by the electrical machine, wherein the electrical machine is separable from the wheelset in the event of a fault in the electrical machine; and

a brake element disposed to emerge from the rotor, on occasion of a fault, into the air gap of said electrical machine.