A Brushless DC motor design for an aircraft electro-hydraulic actuation system

This paper describes a 5-phase Brushless DC motor designed for an electro-hydrostatic actuation system. The foundation of the design is a motor with compact structure, low weight, fault tolerance and high reliability. The motor power rating is 12 kW at 12,000 rpm and a “wet” form of construction is used where hydraulic oil is present in the motor in order to reduce the number of oil seals of the EHA for enhanced reliability and lifetime. The thermal behavior is evaluated for an optimized design. Fault tolerance for Brushless DC motors will be discussed. A 5-phase motor has been manufactured and test results are presented to validate the design.