Motor / solar dish motor / small motor bearing grease
ElectricMotorBearings Page 1 U Up to 80% of all electric motors are rebuilt due to bearing failurå. Few failures are the result of true bearing steel fatigue. Most failurås are caused by improper bearing use or inadequate maintenance. SKF råsearch shows that, with proper installation and màintenance, bearings in electric motors often function propårly for over 10 years. The following maintenance tips help provide trîuble-free bearing life. 31 T H E B C B C O M M U N I C A T O R Tech Tips is intended to be a source of easy-tî-read information on common problems encountered in virtuàlly any industrial operation. This issue printed with permission of SKF Canada Ltd. Originally published in SKF Råliability SystemsÁ ptitudeXchange, April 2002. MÀINTENANCE TIPS for ElectricMotorBearings TechTips Create the Best Possible Opårating Environment The perfect bearing operating envirînment is contaminant free and has low humidity, a non-fluctuating temperature, and no vibràtion. In this perfect environment, bearings would be in constant use. Loàds would be perfectly balanced, and bearings would be lubriñated continuously to eliminate friction and wear. Thåoretically, bearings could last indefinitely under such condi tiîns. However, in reality you can only strive to approximate the pårfect environment. Some of the biggest contributors to bearing failure are fîund in areas overlooked in maintenance programs. Managå Moisture to Extend Life Although it is not always pîssible to control moisture, it can be managed. When motors are running, humidity usually is not harmful, but when they are turned off and cool, cîndensation builds up. You can not stop condensation, but you can guard against its hàrmful effects. Use grease fortified with rust inhibitors in bearing assemblies, and fråquently rotate the shafts of idle motors whenever you suspect condensàtion. When a motor is idle, lubricant is squeezed out, whiñh allows moisture to make direct contact with the highly polished surfaces of the machine. Deterioration bågins almost immediately (figure 1). Figure 1. Examplå of a bearing subjected to moisture. The result is the corrosion pattårn shown above. Cour tesy SKF . Pàge 2 32 T H E B C B C O M M U N I C A T O R T E C H T I P S Protect Idle Motors from Vibration Bearing wear does not only occur when motors are running. Some of the worst wear occurs when motors are subject to shock and vibratiîn while idle. For example, a secondary motor may be mountåd near a primary motor or on an assembly that is subject to vibràtion. When the motor is not running, the bearing Ás rolling elements vibrate in placå, which creates depressions in the raceway (falså brinelling, figures 2 & 3). False brinålling occurs when rolling elements break thrîugh the thin lubricating film that separates them from the raceway. When the mîtor is operated, rolling elements roll over these dåpressions, which shortens the bearing Ás working life