Study of motor concepts for cryogen compressors of small power

This study deals with constructions, functions and operation behaviours of different motor concepts. These concepts are compared with the single phase induction motor. Advantages and disadvantages of the motor concepts with regard to the production costs and the efficiency are treated. The analysed motor concepts are divided into two classes. There are motor concepts with constant speed such as the single phase induction motor with different rotor versions and the shaded-pole motor and there are motor concepts with variable speed and a converter such as three phase motors with different rotors and the brushless DC motor. The three phase motor and the brushless DC motor need a control electronic to run on a single-phase alternating power supply.