TABLE OF CONTENTS Refer to Figure B-1 for this section.
Item 1 in the figure is the electric motor. The most common inspection on the motor during operation is for heat. The motor should be approximately 20 to 25 F higher in temperature than its surrounding environment. If the motor is higher in temperature than this, its life will be shortened due to the effect the heat has on the insulation. For every additional 20 -temperature rise, the life of the insulation will be cut in half. When the insulation fails, so does the motor. If the temperature of the motor becomes too high, efforts should be made to find the problem, so the motor can be cooled back down.
1A denotes the bearings that support the rotating part of the motor (usually the rotor or the armature). The inspection of the bearings should consider three basic factors: heat, noise, and vibration. These three indicators of trouble may appear singly or in any combination. Monitoring these three conditions may require nothing more than the use of your normal senses. If the equipment is critical in nature, it may require the use of some monitoring or nondestructive testing equipment. For measuring the temperature, some form of hand-held thermometer may be used. If the bearings are in a difficult-to-reach or unsafe location, a permanent monitor may be used. If vibration is to be checked, the use of a hand-held...
