Patent ID: 9745897
Date: 2017-08-29
CPC Classifications: F01D,F02C,F05B,F05D,H02P

Claim:
1. An auxiliary power unit (APU) comprising: a gas turbine engine, and a starter generator to be selectively driven by said gas turbine engine; a sensor for sensing windmilling associated with said starter generator, and a lock feature for limiting rotation within said starter generator when windmilling is sensed; and said starter generator includes a DC powered stator and rotor, and said lock feature includes a selective supply of AC power to said stator to limit said rotor from rotation relative to said stator, the selective supply of AC power resulting in sinusoidal variation of negative to positive polarity, and resulting in said rotor being driven in reverse rotations in small amounts of angular movement to limit said rotor from rotation relative to said stator.