Design of a Direct On-Line Induction Motor for Variable Frequency Aerospace Application

There has been much activity over recent years to advance electrical equipment and sub-systems within the aerospace arena. One important development is the Goodrich Integrated Actuator Package (IAPTm) in which an electrical motor drives a hydraulic pump. This in turn provides the power for a hydraulic ram which operates, for example, the aileron surface of an aircraft. This paper describes the work undertaken to demonstrate the potential use of an induction motor as the pump drive. A simple robust supply system for the induction motor is chosen in which the motor is directly connected to an engine-driven generator. The power requirements of the system are discussed and the design of two different motor configurations to meet the requirements is described. The first of these uses a single winding connection. The second, which is shown to have advantages, uses a star/delta switch-over during operation. The steady state and transient operation of the machine are modelled and it is demonstrated that the drive meets the requirements.