Bently Nevada 81546-01 Dual Hermetic Relays Module

The GE / Bently Nevada 3300/45 Dual Differential Expansion Monitor provides two channels of continuous differential expansion monitoring. Both the magnitude and direction of differential expansion are monitored. Four alarm setpoints (two over and two under alarms) can be set for each channel. Channel B of the monitor can be turned OFF for machines requiring the measurement at only one location.
Differential Expansion is the measurement of the axial position of the rotor with respect to the machine casing at some distance from the thrust bearing. Changes in axial position relative to the casing affect axial clearances and are usually the result of thermal expansion during startup and shutdown. The measurement is typically made with a proximity probe transducer mounted to the machine casing and observing an axial surface (e.g., collar) of the rotor. The measurement is usually incorporated as part of a Turbine Supervisory Instrumentation system.