Cis Amrein : sensors and measuring systems

DDx type dual coal based Pendulum transducers

The DD2,DD3, DD5, DD6 and DD8 pendulum transducers perform the measurement of the differential expansion on turbogenerators and similar rotating machines. The DD5 pendulum transducer performs the measurement of the shaft axial position.
The basic principle of operation is a suspended magnet which follows a shaft collar displacement. The sensor element is a pair of accurate coils, measuring the displacement of a target plate. The slim and vertical design of a DD2 transducer allows its mounting on the machine at relatively narrow locations.The rugged design and the continuous further development of the transducers assures a reliable and accurate measurement over the life time of a machine.
Compared with other measurement systems, the pendulum transducer principle allows the translation of the measuring point to a more protected (steam leaks) and cooler area, which minimise also the temperature effect on the measurement.
Furthermore, the actual measurement is performed onto a target made of reference steel, avoiding measurement discrepancies due to various steel qualities, as may occur with direct measurements onto the shaft. Dedicated DD-transducer interfaces are standard in all CIS AMREIN monitoring systems.