330850-90-05 25毫米传感器系统

Description

330850-90-05 25毫米传感器系统

330850-90-05 25毫米传感器系统

The 330850-90-05 25 mm Transducer System consists of a separate25 mm probe, an extension cable, and a 330850-90-05 25 mmProximitor Sensor.  The 0.787 V/mm (20 mV/mil) output givesthis system a linear range of 12.7 mm (500 mils).  Based onthis linear range, the 330850-90-05 25 mm Transducer System issuitable for measuring differential expansion (DE) on midsize to large steam turbine generators caused by thedifference in growth rates between the turbine rotor and themachine stator (casing).

The Differential Expansion measurement is made by twoproximity transducers observing a collar or ramp somedistance from the thrust bearing.  Typical transducermounting arrangements are:

l Two transducers observing the same side of a collar.
l Two complementary input transducers observingopposite sides of a collar, effectively doubling themeasurable DE range.

Two transducers with at least one transducer viewing a rampon a rotor and the second transducer viewing either aseparate ramp or a different location on the rotor tocompensate for radial movement.  This arrangement addssome error to the measurement, but can measure a longertotal DE distance than the complementary measurement.

The criteria for selecting a mounting method are the size ofthe available target, the expected amount of rotor axialmovement and the type of DE target that exists in themachine (collar versus ramp).  If sufficient collar height isavailable, two transducers observing the same side of a collar is the preferred configuration.  These twotransducers provide redundant measurements.