1. The main purpose of electrical equipment maintenance is to:
(A) Ensure reliability and prolong equipment life
(B) Reduce load
(C) Increase voltage
(D) Reduce generation
2. Preventive maintenance is carried out:
(A) Randomly
(B) Only after a breakdown
(C) Only during emergencies
(D) At regular intervals regardless of equipment condition
3. Corrective maintenance is performed:
(A) After a fault or breakdown
(B) Periodically
(C) Before commissioning
(D) During inspection only
4. The main tool used for insulation resistance testing is:
(A) Megger
(B) Voltmeter
(C) Ammeter
(D) Clamp meter
5. Insulation resistance should be measured:
(A) Only after a fault
(B) Only during installation
(C) Regularly to detect deterioration
(D) Randomly
6. The insulation resistance of motor windings should be:
(A) Above 1 MΩ for safe operation
(B) Below 0.1 MΩ
(C) Zero
(D) 100 Ω
7. The primary cause of motor failure is:
(A) Low current
(B) Excess voltage only
(C) Insulation breakdown
(D) Short circuit in line
8. Bearings in electrical machines should be lubricated:
(A) Periodically to reduce friction
(B) Only once during installation
(C) Not required
(D) Continuously without intervals
9. Vibration in motors indicates:
(A) Misalignment, loose parts, or worn bearings
(B) Normal operation
(C) Low voltage only
(D) High frequency only
10. A thermal overload relay protects a motor against:
(A) Short circuits only
(B) Excessive current over time
(C) Low voltage only
(D) Phase reversal only
11. Overcurrent protection is provided by:
(A) Fuses and circuit breakers
(B) Switches only
(C) Transformers only
(D) Insulators
12. Core cleaning of transformers prevents:
(A) Frequency variation
(B) Voltage rise
(C) Overheating and loss of efficiency
(D) Short circuit
13. The purpose of dielectric testing in transformers is to:
(A) Check insulation strength
(B) Check winding resistance
(C) Check voltage
(D) Measure current
14. Regular maintenance of circuit breakers ensures:
(A) Reduced power factor
(B) Increased voltage
(C) Proper operation during faults
(D) Reduced load only
15. In DC machines, commutators should be:
(A) Smooth and clean for proper current flow
(B) Rough
(C) Left dirty
(D) Not connected
16. Brushes of DC machines should be:
(A) Painted
(B) Left loose
(C) Properly seated and lubricated
(D) Removed
17. A megger test is performed at:
(A) Rated voltage or as per manufacturer specification
(B) Zero voltage
(C) Half rated voltage
(D) Twice rated voltage only
18. Thermographic inspection helps to detect:
(A) Phase reversal
(B) Voltage fluctuation
(C) Load variations
(D) Hot spots and overloaded connections
19. In preventive maintenance, check sheets include:
(A) Insulation resistance, lubrication, tightness of connections
(B) Voltage only
(C) Current only
(D) Frequency only
20. Motors showing unusual noise should be:
(A) Stopped and inspected for mechanical faults
(B) Left running
(C) Reconnected immediately
(D) Increased load
21. Oil in transformers should be tested for:
(A) Viscosity only
(B) Dielectric strength and moisture content
(C) Color only
(D) Smell only
22. The main cause of transformer failure is:
(A) Insulation breakdown and overloading
(B) Low frequency
(C) High voltage only
(D) Low voltage only
23. In induction motors, rotor maintenance includes:
(A) Checking for broken bars or loose connections
(B) Only insulation
(C) Only bearings
(D) Only winding
24. Surge protection devices protect equipment against:
(A) Frequency variation
(B) Overcurrent only
(C) Low voltage only
(D) Overvoltage and lightning surges
25. Electrical connections should be:
(A) Tight and free from corrosion
(B) Loose for flexibility
(C) Painted
(D) Not important
26. Insulators should be checked for:
(A) Cracks, contamination, and deterioration
(B) Color only
(C) Voltage only
(D) Frequency only
27. Periodic testing of protective relays ensures:
(A) Increased voltage
(B) Correct operation during faults
(C) Reduced load
(D) Reduced efficiency
28. Overheating in motors is mainly caused by:
(A) Overload, low voltage, or poor ventilation
(B) Proper load
(C) High efficiency
(D) Low resistance
29. Insulation in cables should be:
(A) Painted
(B) Left as is
(C) Free from cracks and moisture
(D) Cut short
30. A multimeter is used for:
(A) Measuring voltage, current, and resistance
(B) Measuring only voltage
(C) Measuring only current
(D) Measuring insulation only
31. Proper labeling of electrical equipment helps to:
(A) Avoid mistakes during maintenance
(B) Increase load
(C) Reduce voltage
(D) Step up current
32. Faulty capacitors in equipment can cause:
(A) Overvoltage only
(B) Reduced power factor and heating
(C) Reduced current only
(D) Frequency drop only
33. Safety during maintenance requires:
(A) Isolation of equipment and use of PPE
(B) Only tools
(C) Only voltage measurement
(D) No safety precautions
34. Energy meters should be maintained by:
(A) Painting only
(B) Rewiring only
(C) Changing rating
(D) Periodic calibration
35. Thermistors or temperature sensors in motors are used to:
(A) Detect overheating
(B) Measure voltage
(C) Measure frequency
(D) Measure resistance
36. Cleaning of switchgear prevents:
(A) Voltage drop
(B) Overload only
(C) Arcing and insulation breakdown
(D) Frequency variation
37. Brushes in AC commutator machines should be:
(A) Properly seated and replaced if worn
(B) Loose
(C) Removed
(D) Painted
38. Thermal imaging cameras detect:
(A) Hot spots and overheating connections
(B) Voltage
(C) Frequency
(D) Current only
39. Protective earth connections are important to:
(A) Improve load factor
(B) Reduce voltage
(C) Increase frequency
(D) Prevent electric shock
40. Tightening of terminals prevents:
(A) Overheating and voltage drop
(B) Overvoltage
(C) Reduced frequency
(D) Low power factor
41. Motor winding resistance measurement helps to detect:
(A) Open or shorted turns
(B) Voltage rise
(C) Frequency drop
(D) Power factor
42. A regular maintenance schedule improves:
(A) Equipment reliability and safety
(B) Voltage only
(C) Frequency only
(D) Load only
43. DC motor armature should be checked for:
(A) Current only
(B) Voltage only
(C) Shorts, opens, and commutator condition
(D) Load only
44. Transformer oil should be filtered to remove:
(A) Moisture and impurities
(B) Voltage only
(C) Load only
(D) Current only
45. Overvoltage in motors can cause:
(A) Insulation failure
(B) Low power factor
(C) Low voltage
(D) Reduced load only
46. Loose connections in electrical panels can lead to:
(A) Reduced voltage only
(B) Sparking and overheating
(C) Frequency variation
(D) None
47. Maintenance of emergency lighting ensures:
(A) Proper operation during power failure
(B) Reduced voltage
(C) Reduced frequency
(D) Overload protection
48. Equipment maintenance records help to:
(A) Reduce voltage
(B) Increase load
(C) Track history and plan preventive maintenance
(D) Reduce frequency
49. Insulation testing should be done:
(A) Before commissioning and periodically
(B) Only after faults
(C) Randomly
(D) Only during breakdown
50. A safety switch is used to:
(A) Reduce current
(B) Increase voltage
(C) Disconnect equipment during maintenance
(D) Measure load