Sundstrand Corporation

James A Shippling

Gregory I Rozman

Albert L Markunas

Malcolm J McArthur

Leland E Weber

Kenneth R Carr

Vietson M Nguyen

Vijay K Maddali

Alexander Cook

Michael J Hanson

Paul E Nuechterlein

Mario R Rinaldi

A control for a brushless generator operable in starting and generating modes supplies combined AC and DC power to an exciter field winding of the brushless generator during operation in the starting mode. The magnitude of a parameter of the AC power is decreased with increasing rotor speed during operation in the starting mode until a particular rotor speed is reached, following which only DC power is supplied to the exciter field winding.

Control for a brushless generator

A control for operating an electromagnetic machine in a starting mode of operation wherein the main armature winding of the machine receives electrical power from a controllable power source during the starting mode of operation, comprises a circuit for detecting a magnitude of a parameter of power applied to the main armature winding relative to a stationary frame of reference, a position sensor for detecting rotor position of the electromagnetic machine, a converter responsive to angular position indication for converting the detected parameter magnitude into field and torque producing components relative to a rotating frame of reference, and a circuit responsive to the field and torque producing components for controlling the power source during operation in the starting mode. This control includes an igniter for igniting a prime mover. Further, the control is operable during a first phase prior to ignition of the prime mover for causing the electromagnetic machine to provide motive power to the prime mover so as to accelerate the prime mover at a first predetermined rate, is operable during a second phase subsequent to the first phase so as to accelerate the prime mover at a second predetermined rate, is operable during this second phase for providing fuel to the prime mover to facilitate ignition thereof, and is operable during a third phase subsequent to the ignition of the prime mover so as to accelerate the prime mover at a third predetermined rate to a self-sustaining speed.

Engine starting system utilizing multiple controlled acceleration rates

A method of controllably starting a prime mover, such as a gas turbine engine for an aircraft, in which the prime mover is coupled to a synchronous machine operable in a generating mode in which the synchronous machine converts motive power generated by the prime mover into electrical power and in a starting mode in which the synchronous machine provides motive power to the prime mover to accelerate the prime mover to self-sustaining speed includes three controlled phases: a pre-ignition phase, an ignition phase, and a torque augmentation phase. During each phase the prime mover is accelerated at a predetermined rate. When the motive power provided by the synchronous machine falls below a predetermined level, its operation is converted from its starting mode to its generating mode.

Controlled starting method for a gas turbine engine

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Erie, PA, United States of America

James A Shippling