Patent ID: 8743520

Claim:
A method for protecting a multi-phase autotransformer for an aircraft, the method comprising: receiving at least one value of current output from (I a , I b , I c ) a first phase of the autotransformer, at least one value of current input into (I A , I B , I C ) a second phase of the autotransformer and at least one value of current output from (I a , I b , I c ) the second phase; determining, at least as a function of the values of currents input into (I A , I B , I C ) and output from (I a , I b , I c ) the second phase, at least one value of current representative of the operation (I Fa , I Fb , I Fc ) of the second phase; determining, at least as a function of the value of current representative of the operation (I Fa , I Fb , I Fc ) of the second phase and of the value of current output from (I a , I b , I c ) the first phase, at least one value representative of the homopolar current (I det-a ,I det-b , I det-c )flowing in the first phase; comparing the value representative of the homopolar current (I det-a , I det-b ,I det-c ) flowing in the first phase with a first predetermined threshold value (S1) at least during a first predetermined period (D1); and controlling the values of currents input into (I A , I B , I C ) or output from (I a , I b , I c ) the phases of the autotransformer as a function of the comparing.