Overheating, scorching odors and smoke are signs of shorts or serious overload, rating. Ctop machine and check load conditions against the Check the drive and driven machine to see that they do not im- pose an excessive friction load on the machine. coils or armature. erly adjusted. Test for short in field ‘See that brushes and brush-spring pressure are prop- See that there is a free circulation of air around the machine so that ventilation is not restricted. Make a periodic examination of all field windings, field poles, and all cable connections for tightness. Tighten all brush studs that may have developed slack due to drying out of washers, and make certain the studs are not displaced. Inspect the mechanical drive to see that it is properly adjusted and in alignment. LUBRICATION OF BALL BEARINGS When the machine is shipped, the bearings are packed with the proper amount of high grade grease. Touble sealed, prelubricated bearings are packed with a special grease by the bearing manufacturer. Machines with such bearings can be identified by the absence of grease fittings. The grease used will ordinarily maintain its lubricating qualities for the life of the bearing under normal operating conditions. Where high operating temperatures are encountered, the life of the bearing may be limited to the time the lubricant will last. Ball bearings consume only a very small amount of lubricant but enough must be present at all times to avoid injuries. The length of time a bearing can run without having grease added or replaced will depend upon the operating conditions. 3-47