Study and design of an asynchronous electrical machine with inverted construction

The paper refers to the study, design and some trials and tests of a 1 kW high-speed three-phase asynchronous electric machine that is achieved in inverted construction. This electric machine is in inverted construction that is with the rotor on the outside. The rotor of the electric machine is in a copper cage, to increase efficiency and space saving. Electrical tests were performed in motor and electric generator mode. Finite element modelling of the magnetic field was done in FEMM. Dynamic balancing tests were also performed. Mechanical stresses were analysed, and thermal stress calculations were performed. The control of the inverted high-speed asynchronous machine at variable speed was done with a frequency converter. The practical and theoretical results obtained prove a solid construction of the electric machine at variable frequencies, from o to 100 Hz. The three-phase asynchronous electric machines in inverted construction have several advantages, such as high efficiency and space saving. This advantages that make them viable for important specific applications, such as aircraft and electric vehicles.