Rockwell Automation Allen-Bradley 7712, User Manual

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Rockwell Automation Publication 7712-UM001D-EN-P - October 2017 49
Maintenance Chapter 5
3. Measure dimension A1 for all three bottles with the contactor still
energized ( Figure 31 ).
4. De-energize (drop out) the contactor and measure dimension A2 for all
three bottles.
The contact gap is the difference of A2 minus A1. Record the gap for all
three bottles.
Figure 31 - Measuring Contact Gap
5. Tighten the load terminal nut on each bottle assembly.
Apply wrenches to the load terminal nut and to the flattened section of
the movable bottle shaft to prevent damage to the bellows.
6. Tighten the load terminal nut while holding the bottle shaft steady.
Do not turn the insulator as this changes the gap.
7. The final contact gap for all three bottles must be between
0.180...0.200 in. (4.57...5.08 mm). If this is the case, the replacement
procedure is complete.
If further adjustment is required, all three gaps can be adjusted
simultaneously by loosening the stop bracket bolts and adjusting the
height of the gap adjustment screw at the rear of the contactor
( Figure 32 ). To adjust the height of the screw, first loosen the locking
nut.
8. When the gap is correct, tighten the gap adjustment screw locking nut.
9. Position the stop bracket lightly against the armature plate and tighten
the bolts securing the stop in position.
Ensure that the actuator plate contacts the gap adjustment screw and the
armature plate contacts the stop bracket ( Figure 32 ).
IMPORTANT The contact gaps must be synchronized within 0.02 in. (0.5 mm). If the gaps
are not synchronized, rotate the insulators as required. The overtravel must
remain at least 0.065 in. (1.65 mm) on each bottle.
A1
A2