Which is the correct minimum maintenance frequency for greasing motor bearings on electrical systems?

• A. Annually
• B. Monthly
• C. Weekly
• D. Never

Answer: (A)

Lubrication intervals for motor bearings revolve around keeping the grease life within a safe range so the bearings stay cool and run smoothly. For typical electrical motors with greased, non-sealed bearings, the minimum maintenance frequency is annual. Doing it once a year acts as a baseline to refresh degraded grease, remove contaminants, and counter grease bleed-off and temperature effects. If bearings aren’t lubricated or greased often enough, friction and heat can rise, leading to wear and potential failure. More frequent relubrication is needed only in harsher service conditions—high temperatures, dirty or wet environments, high vibration, or frequent starts and stops—where the interval may be shortened. Conversely, some motors with sealed bearings don’t require greasing at all, but in standard practice for commonly used systems, annual is the safe minimum.