Reducing fault energy from an electric motor drive for a compressor
A system has an electric motor having a stator and a rotor. The rotor rotates with a shaft and the shaft drives a fluid rotor. A control senses a fault condition on the electric motor. The control actuates a speed reduction feature when a fault is detected to bring rotation of the motor rotor and the fluid rotor to a stop more rapidly than if the speed reduction feature had not been actuated.
1. A system comprising:
an electric motor having a stator and a motor rotor, said motor rotor rotating with a shaft, and said shaft driving a fluid rotor;
a control for sensing a fault condition on said electric motor, and said control being configured to stop flow of current in response to a fault being detected, and to actuate a speed reduction feature in response to the fault to bring rotation of said motor rotor and said fluid rotor to a stop;
said motor rotor is a permanent magnet rotor; and
said speed reduction feature being at least one of moving a variable diffuser for the fluid rotor to a more open position or opening a valve to deliver air from an outlet of the fluid rotor into an inlet of the fluid rotor.
2. The system as set forth in claim 1 , wherein said fluid rotor is a compressor impeller.
3. The system as set forth in claim 1 , wherein said speed reduction feature is moving the variable diffuser for the fluid rotor to a more open position.
4. The system as set forth in claim 3 , wherein the speed reduction feature also includes opening the valve to port air from an outlet of said fluid rotor into an inlet of said fluid rotor.
5. The system as set forth in claim 1 , wherein the speed reduction feature is opening the valve to deliver air from an outlet of said fluid rotor into an inlet of said fluid rotor.
6. The system as set forth in claim 5 , wherein said valve is an add heat valve.
7. An air supply system on an aircraft comprising:
a motor having a stator and a motor rotor, said motor rotor rotating with a shaft, and said shaft driving a compressor impeller;
a control for sensing a fault condition on said electric motor, and said control being configured to stop flow of current in response to a fault being detected, and to actuate a speed reduction feature in response to the fault to bring rotation of said motor rotor and said compressor impeller to a stop;
said motor rotor is a permanent magnet rotor; and
said speed reduction feature being at least one of moving a variable diffuser for the fluid rotor to a more open position or opening a valve to deliver air from an outlet of the fluid rotor into an inlet of the fluid rotor.
8. The air supply system as set forth in claim 7 , wherein said compressor impeller is configured to deliver air to a downstream use on the aircraft.
9. The air supply system as set forth in claim 8 , wherein said downstream use includes delivering air into a cabin for said aircraft.
10. The air supply system as set forth in claim 7 , wherein said speed reduction feature is moving the variable diffuser to a more open position.
11. The air supply system as set forth in claim 10 , wherein the speed reduction feature also includes opening the valve to port air from an outlet of said compressor impeller into an inlet of said compressor impeller.
12. The air supply system as set forth in claim 7 , wherein the speed reduction feature is opening the valve to deliver air from an outlet of said compressor impeller into an inlet of said compressor impeller.
13. The air supply system as set forth in claim 12 , wherein said valve is an add heat valve.
14. A method of operating a compressor comprising the steps of:
sensing a fault condition on a permanent magnet electric motor driving a fluid rotor, and stopping supply of current to the electric motor, and actuating a speed reduction feature when a fault is detected to bring rotation of said fluid rotor to a stop; and
said speed reduction feature being at least one of moving a variable diffuser for the fluid rotor to a more open position or opening a valve to deliver air from an outlet of the fluid rotor into an inlet of the fluid rotor.
15. The method of operating a compressor as set forth in claim 14 , further comprising delivering air to a downstream use on an aircraft with the fluid rotor.
16. The method of operating a compressor as set forth in claim 14 , wherein actuating said speed reduction feature includes opening a flow area in the variable diffuser.
17. The method of operating a compressor as set forth in claim 16 , further comprising also opening the valve to deliver air from an outlet of said fluid rotor into an inlet of said fluid rotor as said speed reduction feature.
18. The method of operating a compressor as set forth in claim 14 , wherein the speed reduction feature is opening the valve to deliver air from an outlet of said fluid rotor into an inlet of said fluid rotor.