Bently Nevada

The 330930-040-05-CN 3300 XL 25 mm Transducer System consists of a separate 25 mm probe, an extension cable, and a 3300 XL 25 mm Proximitor Sensor.  The 0.787 V/mm (20 mV/mil) output gives this system a linear range of 12.7 mm (500 mils).  Based on this linear range, the 3300 XL 25 mm Transducer System is suitable for measuring differential expansion (DE) on midsize to large steam turbine generators caused by the difference in growth rates between the turbine rotor and the machine stator (casing).

The Differential Expansion measurement is made by two proximity transducers observing a collar or ramp some distance from the thrust bearing.  Typical transducer mounting arrangements are:
-Two transducers observing the same side of a collar.
-Two complementary input transducers observing opposite sides of a collar, effectively doubling the measurable DE range.
Two transducers with at least one transducer viewing a ramp on a rotor and the second transducer viewing either a separate ramp or a different location on the rotor to compensate for radial movement.  This arrangement adds some error to the measurement, but can measure a longer total DE distance than the complementary measurement.