Comparison of Different Actuator Concepts for Applications in Rotating Machinery

Considerable improvements of machines can be expected in the near future through the use of electronics in combination with control techniques. A key position will be held by the actuator systems that finally have to accomplish the controlled energy transfer according to the objectives. For rotating machine parts this is usually done via the bearings. Basically, there are two possibilities to transmit the controlled forces; contact free via magnetic fields (magnetic bearings) or the traditional way via conventional bearings. To realize the regulating actions multiple physical effects can be employed. In this paper some of the promising types of actuators and their advantages and disadvantages will be discussed, as well as how effectively to use these active elements under different objectives. Questions concerning the practical realizations will be given high priority.