Shaft break detection

摘要

A shaft break detection system and a method of detecting shaft break for a gas turbine engine comprises measuring rotational speed of a shaft of a gas turbine engine. A first indication is calculated from the rotational speed of the shaft. A second indication is calculated from the rotational speed of the shaft. A shaft break signal is generated if both indications are true. The first indication may be true if the rate of change of rotational speed indicates deceleration greater than a threshold. The second indication may comprise performing a frequency analysis on a rate of change of the rotational speed or a frequency analysis on the rotational speed. The second indication is true if the frequency analysis indicates no peak at a first torsional frequency of the shaft. The second indication may comprise testing a hypothesis that the shaft and its coupled components behave as a second order system with the second indication true if the hypothesis is false. The shaft break indication may alternatively be true if the first and second indications and an additional indication are true.