EMERSON A6210 Thrust Position,Rod Position Monitor,and Differential Expansion

EMERSON A6210 Thrust Position,Rod Position Monitor,and Differential Expansion

The A6210 monitor operates in 3 distinct modes: thrust position, differential expansion, or rod position.

The Thrust Position mode accurately monitors thrust position and reliably provides machinery protection by comparing the measured axial shaft position against alarm set-points – driving alarms and relay outputs.

Shaft thrust monitoring is one of the most critical measurements on turbomachinery. Sudden and small axial movements should be detected in 40 msecs or less to minimize or avoid rotor to case contact. Redundant sensors and voting logic are recommended.Thrust bearing temperature measurement is highly recommended as a complement to thrust position monitoring.

The shaft thrust monitoring consists of one to three displacement sensors which are mounted parallel to the shaft end or thrust collar. Displacement sensors are non-contact sensors used to measure the position of the shaft.

For extremely critical safety applications, the A6250 monitor provides triple-redundant thrust protection built on the SIL 3-rated overspeed system platform.

The A6210 monitor can also be configured for use in differential expansion measurement.
As thermal conditions change during turbine startup, both the casing and rotor expand, and differential expansion measures the relative difference between the displacement sensor mounted on the casing and the sensor target on the shaft. If the casing and shaft grow at approximately the same rate, the differential expansion will remain close to the desired zero value. Differential expansion measurement modes support either tandem/complementary or tapered/ramp modes

Finally, the A6210 monitor can be configured for Average Rod Drop Mode - useful for monitoring brake band wear in reciprocating compressors. Over time, the brake band in a horizontal reciprocating compressor wears due to gravity acting on the piston in the horizontal orientation of the compressor cylinder. If the brake band wears beyond specification, the piston may contact the cylinder wall and cause machine damage and possible failure.

By installing at least one displacement probe to measure the piston rod position, you will be notified when the piston drops - this indicates belt wear. You can then set the shutdown protection threshold for automatic tripping. The average rod drop parameter can be broken down into factors representing actual belt wear, or without applying any factors, the rod drop will represent actual movement of the piston rod.

AMS 6500 easily integrates into DeltaV and Ovation process automation systems and includes preconfigured DeltaV Graphic Dynamos and Ovation Graphic Macros to speed operator graphics development. AMS software provides maintenance personnel with advanced predictive and performance diagnostic tools to confidently and accurately identify machine failures early.