Page 208 - Machinery Component Maintenance

190 Machinery Component Maintenance and Repair

J.
I-1
Shaft or Coupling
Measurement Surface
Error due to curvature Difference in indicator
(usually slight if diameter
positions before and after
exceeds 2 'I). corrective movement or
1 180° shaft rotation.

Figure 5-13. Error can be induced due to curvature effect on misaligned components.

If this surface is not level
at top dead center,
inclined-plane effect can
nn ,cause major errors.

center. For
reverse-indicator setups,
a second surface will be
required at the other shaft
or coupling half, levelled
at bottom dead center
coincident with first
surface being levelled at Difference in indicator
top dead center. positions before and after
corrective movement or
1 80° rotation

Figure 5-14. Auxiliary flat surface added to avoid curvature-induced measurement error.