Cross-Coupling - GE Bently Nevada 7200 Series Installation Manual

the observed surface can cause electrical or mechanical runout which will introduce error in the
Proximitor output.
The various techniques for eliminating electrical and mechanical runout are described in several
papers available from Bently Nevada Corporation, including:
•
Dealing with "Glitch". Where does Electronic Vectorial Runout Compensation Fit In?
(Application Note 004)
•
"Glitch": Definition of and Methods for Correction, including Shaft Burnishing to Remove
Electrical Runout. (Application Note 011)
The electromagnetic fields of probe tips mounted too closely together will cross-couple, causing a
small amplitude ac signal to be superimposed on the Proximitor outputs. To prevent cross-coupling
mount the probes so that the distance between the tips is at least as large as that shown in the Figure
2-1.
Because the electromagnetic field also extends outward from the side of the probe tip, it is necessary
to remove all conductive material from around the tip as shown in Figure 2-2. If this is not done,
A = 28 mm (1.1 inches) minimum
B = 82 mm (3.2 inches) minimum
C = 64 mm (2.5 inches) minimum
D = 61 mm (2.4 inches) minimum
Figure 2-1. Cross-Coupling
Section 2 - INSTALLATION
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