United Technologies Corporation

Robert M Vannini

Joseph M Kos

Robert D Shangraw

James E Neville

A method and control system for modulating a starter turbine (14) speed to a predetermined reference speed to prevent crash engagement with a turbine engine (16) during restart. The turbine engine (16) is coupled to the starter turbine (14) by a ratchet and pawl clutch (17), and crash engagement is prevented by modulating the starter turbine (14) speed to the predetermined reference speed, which is below a minimum pawl engagement speed, until the pawls have locked-in. A control system (10) in accordance with the present invention includes an electronic control (18) section and a mechanical pneumatic actuation means (20) which operate to limit the speed of the starter turbine (14) to the predetermined reference speed which is below the minimum speed at which crash engagements occur. The electronic control (18) provides an adjustment signal (26) corresponding to the difference between a sensed starter turbine speed signal (24) and a reference speed signal (49). The mechanical pneumatic actuation means (20) modulates an air flow into the starter turbine (14 ) in response the adjustment signal (26), thereby modulating the speed of the starter turbine (14) to the predetermined reference speed.

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Longmeadow, MA, United States of America

Robert M Vannini