Electromagnetic compatibility of the machine measuring equipment in RFX experiment

In the RFX experiment many kinds of transducers are used in order to measure a great deal of parameters related to the machine monitoring, control and protection. Such devices have to be located and are called to operate in a rather noisy environment. A first source of possible electromagnetic interference is represented by the air-core ohmic heating magnet system, which produces a magnetic field relatively strong within a wide area around the machine. Further sources of noise have been identified in the Power Supply system. In the paper, after a description of the principal measurement requirements and of the expected noise sources, the possible physical mechanisms by which noise and signals can be coupled are shown. A detailed explanation of the precautions taken in order to keep the interference within acceptable limits is then given. In particular the design and the shielding criteria of the Local Control Room, where the majority of the control equipment of the Power Supply system are to be located, is presented. The behavior of a type of current transformer, which allows by means of an auxiliary circuit the extension of the frequency response down to DC is also presented, with regard to its electromagnetic compatibility. 10 refs., 8 figs., 2 tabs