Table 13 — External Gear Troubleshooting Guide
PROBLEM
POSSIBLE CAUSE — ITEM NO.s*
Excessive Operating Temperature
1,2,3,4,5,6,7,9,12,18,20,21
Oil Leakage
1,2,3,4,5,7,9,12,13,18,19,21
Gear Wear
1,2,3,4,6,7,8,9,10,11,12,13,14,15,16,18,19,21,22
Bearing Failure
1,6,7,8,9,10,11,12,15,16,19,20,21
Unusual Noise
1,2,3,4,6,7,8,9,10,11,12,13,15,16,17,20,21
*See table below for probable cause and suggested remedy.
POSSIBLE CAUSE
ACTION
1. Unit Overload
Reduce the loading.
2. Incorrect Oil Level
Verify that the oil level is correct. Too little or too much oil can cause high
temperature.
3. Wrong Oil Grade
Use only the AGMA (American Gear Manufacturers Association) grade oil
as specified for the unit size and ambient temperature.
4. Contaminated Oil
If oil is oxidized, dirty, or has high sludge content, change the oil.
5. Clogged Breather
Clean breather regularly.
6. Improper Bearing Clearance
Too large or too small bearing clearance. Refer to drawing or contact the
gear manufacturer for correct clearance, checking technique, and toler-
ance. Shafts should turn freely when disconnected from the load.
7. Improper Coupling Alignment
Disconnect couplings, check spacing between shafts, and check alignment.
Realign as required.
8. Incorrect Coupling
Rigid couplings can cause shaft failure. Replace with a coupling that pro-
vides flexibility and lateral float.
9. Excessive Operating Speed
Reduce the speed.
10. Torsional or Lateral Vibrations
Vibrations can occur through a particular speed range known as the critical
speed. Contact the factory for specific recommendations.
11. Extreme Repetitive Shocks
Apply couplings capable of absorbing shocks.
12. Improper Lubrication of Bearings
Verify that all bearings are receiving adequate amounts of lubricating oil.
13. Improper Storage or Prolonged Shutdown
Destructive rusting of bearings and gears will be caused by storage or pro-
longed shutdown in moist ambient temperatures. If rust is found, unit must
be disassembled, inspected, and repaired.
14. Excessive Backlash
Contact gear manufacturer.
15. Misalignment of Gears
Contact pattern to be a minimum of 80% of face.
16. Housing Twisted or Distorted
Verify proper shimming or stiffness of the foundation.
17. Gear Tooth Wear
Contact gear manufacturer.
18. Open Drains
Tighten drain plugs.
19. Loosely Bolted Covers
Check all bolted joints and tighten if necessary.
20. Motor Related
Verify that actual operating conditions are consistent with motor nameplate.
21. Excessive Ambient Temperature
Shield unit from heat source and maintain proper air flow around the gear
unit.
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