Manitowoc National Crane NBT30H-2, Service Manual

Page: 131 / 194

6
National Crane
03-20-2019 Control # 613-06
6-13
NBT30H-2 SERVICE MANUAL SWING
Slew Potentiometer Adjustment
The slew potentiometer (slew pot) located inside the turret, is
used by the RCL to determine swing position and limits the
swing to 410°—205° left and 205° right. The slew pot needs
to be oriented to 0° (±5°) before the RCL can be calibrated
for the swing parameters.
The following procedure is to mechanically adjust the slew
pot to zero when the slew pot is out of the ±5° specified by
the RCL. This procedure can also be use for installing a new
slew pot.
1. Place the boom at 0° over the truck centerline.
2. Remove the slew pot from the turret.
3. Make sure the slew pot is plugged into the RCL
connector and turn the RCL on.
4. Go to the RCL slew angle calibrate screen as described
in the RCL service manual.
5. Rotate the slew pot gear until the reading on the RCL is
0° (±5°). This reading must be within ±5° of 0° or the
RCL will not calibrate the swing position correctly.
6. Reinstall the slew potentiometer in the turret.
7. Slide the slew pot forward to make sure the slew pot
gear is meshed with the swing bearing teeth.
8. Back off the slew pot gear slightly so that there is a 3.1 to
4.7 mm (0.125 to 0.188 inch) gap between the slew pot
gear teeth and the swing bearing gear teeth.
9. Tighten the bolts on the slew pot bracket.
10. Calibrate the slew angle with the RCL.
NOTE: When verifying the slew angle calibration in step
11, refer to your slew angle calibrate screen.
11. Verify the slew angle calibration by swinging the boom
180° to the right and left according to instructions on the
slew angle calibrate screen.
12. If the readings are not correct, recalibrate the slew angle
with the RCL.
Slew
Potentiometer
FIGURE 6-11
Zero Adjustment
Angle
FIGURE 6-12
±5°
0° is when the boom is over the
rear of the truck centerline,
regardless of mounting
configuration.
0°
CAUTION
There must be 3.1 to 4.7 mm (0.125 to 0.188 inch) gap
between the slew pot gear teeth the swing bearing gear
teeth to keep from damaging the slew pot gear shaft.