Page 279 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

Power Transmission Gears 261

2. If a pump is used, be sure that it is primed to minimize the time
necessary to build up a positive oil pressure. Pressure should build
up in 10 to 15 seconds. If pressure does not develop, stop unit and
determine the problem. When an electric-driven oil pump or some
other remote pump provides lubrication for the gear, it is a good
idea to run that pump a few minutes prior to startup to provide
initial lubrication during startup.
3. Check rotation. Be sure that the gear unit will rotate in the direc-
tion for which it is intended. The shaft-driven oil pump is uni-di-
rectional and must rotate in the direction indicated by the arrow. If
the other direction of rotation is desired, it will be necessary to
replace the pump with one of the opposite rotation from manufac-
turer.
4. Make sure the gears have backlash.
5. Check for free turning of the shafts.
6. Check for correct coupling alignment.
7. Check to see that all necessary piping and accessory wiring is
complete.
8. Check for correct water flow and temperature through the oil
cooler.
9. Check for foundation bolt tightness.
10. Check tooth contact.
11. Make sure there is running clearance around all moving parts.
12. Warning: Coupling guards and inspection covers should be se-
cured before startup.

Checklist After Startup
Each gear installation requires that different operating checks be made
depending on the instrumentation furnished, the size of the unit, and how
the unit is equipped. The following checklist can be used as a rough
guide:

1. Run gear unit at light load and reduced speed if possible while
checking for proper lubrication. After the unit has been running ap-
proximately 15 seconds, the oil should be circulating. If there is a
noticeable drop in oil pressure on pressurized systems after several
hours of operation, clean the oil filter. Occasionally, lint will clog
the filter after initial startup.
2. Watch the bearings for a sudden high temperature rise which could
indicate a bearing problem. In general, the bearing temperature
should be no more than 50°F above the inlet oil temperature or a
maximum of 195°F. These temperatures are very conservative and