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Examoogle • User • info@examoogle.com • EE-2024-8821
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Which activities performed in monthly inspection of I.M.
Bearing
Controller
Winding
and B
and B
Quick Summary: Monthly inspection of an Induction Motor (I.M.) involves routine preventive maintenance checks to ensure operational reliability. Bearings are inspected for lubrication and noise, while controllers are checked for contact wear, loose connections, and cleanliness, making both items essential for monthly maintenance schedules.
Monthly inspection of an Induction Motor (I.M.) involves routine preventive maintenance checks to ensure operational reliability. Bearings are inspected for lubrication and noise, while controllers are checked for contact wear, loose connections, and cleanliness, making both items essential for monthly maintenance schedules.
Tf=μ⋅R⋅r — where Tf is bearing frictional torque, μ is coefficient of friction, R is load, and r is radius.
P=I2R — where P is power loss in controller contacts, emphasizing the need for low resistance connections.
Preventive maintenance relies on the 'Check-Clean-Tighten' principle. Bearings require periodic lubrication and auditory monitoring to detect mechanical friction or wear, while controllers (starters) require electrical continuity and terminal tightness checks to prevent arcing and overheating due to contact oxidation or vibration.
Monthly maintenance is categorized as Preventive Maintenance (PM).
Bearing lubrication prevents overheating and excessive wear of rotating parts.
Controller inspection includes verifying contact pressure and tightening electrical terminals to prevent hot-spots.
Winding insulation resistance (Megger test) is typically performed on a quarterly or semi-annual basis, not monthly.
Increases the Mean Time Between Failures (MTBF).
Ensures safe operation and prevents unscheduled downtime.
Increases operational expenditure due to labor costs.
Minor risks of causing faults during unnecessary disassembly.
Industrial conveyor systems
Pump sets in agricultural and municipal utilities
HVAC cooling tower motors
Winding inspection usually requires a shutdown for insulation resistance testing and is generally scheduled for longer intervals (6 months to 1 year).
Monthly inspections focus on 'external' observable factors; 'internal' factors like winding integrity are part of predictive/major maintenance.
D is correct — Bearing lubrication and controller contact cleaning are both essential components of routine monthly maintenance for an Induction Motor.
Always remember the 'Time-Frequency Hierarchy' in maintenance: Clean/Tighten (Monthly) < Lubricate (Quarterly/Half-yearly) < Insulation Test (Annually).