grease with carbon tetrachloride in a well-ventilated room. -faxe sure there are ao foreign materials in the air gap or other air passageways. If the machine is installed in a dirty place, it should be disassembled and thoroughly cleaned as frequently as the conditions warrant, Listen for any mechanical noises which indicate metal-to-metal contact. If present, shut down the machine as soon as possible and check for misalignment or bearing failure. Overheating, scorching odors and smoke are signs of shorts or seri- ous overload. Stop machine and check load conditions against the rating. Sneck the drive and driven machine to see that they do not impose an excessive friction load on the machine. Test for short in field coils, and see that brushes and brush spring pressure are properly adjusted, cee that there is a free circulation of air around the machine so that ventilation is not restricted. Check control for proper operation of overload protection devices, Make a periodic examination of all field windings, and all cable connections for tightness, Where applicable, tighten all brush studs taat may have develoned slack due to drying out of washers, and make eertain the studs are not displaced. Inspect tie 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. Double sealed, prelubricated bearings are packed with a special grease by the beurine manufacturer. Machines with such bearings can be 3-30