Kistler-Morse KM L-Cell Bolt-On - Manual (Page 51)

Chapter 5. L-Cell Installation on Skirt-Supported Vessels
5-14
5. Holding the L-Cell flat against the surface, loosely fasten the L-Cell
with the three screws. Do not tighten the screws.
• If the voltage goes outside -200 to +200 mV, immediately loosen
the screw(s), as this may indicate a burr or rough surface. Remove
the screws and L-Cell. Check for and remove burrs and surface
roughness (refer to Surface Preparation for removing surface
roughness). Repeat Steps 1 through 5.
CAUTION
For proper installation, tighten each screw until the T-handle driver
flexes in torsion
1 / 4 turn past where the screw stops turning. Repeat
this flexing procedure several times to ensure the screw is tight The
final reading when all screws are tight must be in the range -200 to
+200 mV. Follow Steps 6 through 8 to achieve this goal.
6. Using the T-handle driver, slowly tighten screw S2 while monitoring
the Meter carefully. If the voltage goes outside -200 to +200 mV while
tightening, stop immediately and evaluate the following (Fig 5-28):
• Voltage jumped outside the range — This may indicate a burr or
rough surface. Remove the screws and L-Cell. Check for and
remove burrs and surface roughness (refer to Surface Preparation
for removing surface roughness). Repeat Steps 1 through 6.
• Voltage gradually moved outside the range — Slowly loosen the
screw until the voltage is within range again and proceed to Step
7.
7. Repeat Step 6 for screws S1 and S3.
If the voltage is outside -200 to +200 mV, attempt to bring the reading
within range by loosening the screw being torqued, tightening
another screw(s), or some combination of loosening and tightening. If
you have difficulty staying within the range, try turning each screw
1 / 4 turn at a time until all screws are tightened. (Fig. 29)
Note
If the following occurs while turning screws, check L-Cell resis-
tance using a DMM (described inChapter E, Troubleshooting):
• Voltage does not change or changes less than 25 mV, or
• Voltage changes randomly (i.e., not in a consistent direction).
8. To complete the installation, ensure:
• All three screws are tightened until the T-handle driver flexes in
torsion, 1 / 4 turn past the point where the screw stops turning, with
this flexing procedure repeated several times to ensure the screw is
tight, and
• The voltage is in the range -200 to +200 mV.
9. Prior to installing the environmental cover, ensure the mating surface
is free of dirt and grease. Clean if necessary, being careful not to
remove the rust inhibitor on the bare metal. See Fig. 30.
Figure 5-28. L-Cell Mounting
Notes:
1. Do not apply rust inhibitor outside the
2.50” (63.5mm) diameter bare metal,
or environmental cover will not
adhere properly.
2. Place small amount of sealant on
each screw before mounting L-Cell.
Apply Rust
Inhibitor to
2.50” (63.5mm)
diameter bare
metal surface
S1 #6-32 Cap Screw
S2
S3 #6-32 Cap Screw
Cable Exit Channel
Tape
1/8” (3.2mm)
Bead
All-Around
(wipe smooth)
Tape
Tape
Figure 5-30. Environmental Cover
Figure 5-29. L-Cell install