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Question 1. Which maintenance philosophy focuses on performing tasks only after a failure has occurred? A) Preventive Maintenance B) Predictive Maintenance C) Reactive Maintenance D) Reliability Centered Maintenance Answer: C Explanation: Reactive (run‑to‑failure) maintenance schedules work only after equipment has failed, unlike preventive or predictive approaches that act before failure. Question 2. In a time‑based preventive maintenance program, what primarily determines the interval between inspections? A) Operating hours logged by the machine B) Manufacturer’s recommended calendar schedule C) Real‑time vibration data D) Cost of spare parts Answer: B Explanation: Time‑based PM uses calendar intervals set by the OEM or maintenance policy, independent of actual usage. Question 3. Which condition‑monitoring technology is most commonly used to detect bearing defects in rotating equipment? A) Ultrasonic emission B) Infrared thermography C) Vibration analysis (FFT) D) Oil particle count Answer: C Explanation: Vibration analysis, especially FFT spectra, reveals characteristic frequencies of bearing faults such as outer race, inner race, and rolling element defects.
Question 4. During a Failure Mode and Effects Analysis (FMEA), what does the “Severity” rating describe? A) Likelihood of occurrence B) Ability to detect the failure before it occurs C) Consequence of the failure on system operation D) Cost of corrective action Answer: C Explanation: Severity assesses how serious the impact would be if the failure occurs, separate from its probability or detectability. Question 5. Which of the following is NOT one of the eight pillars of Total Productive Maintenance (TPM)? A) Autonomous Maintenance B) Planned Maintenance C) Continuous Improvement D) Cost‑Based Scheduling Answer: D Explanation: The eight TPM pillars include Autonomous Maintenance, Planned Maintenance, Quality Maintenance, Focused Improvement, Early Equipment Management, Training & Education, Safety, and Office TPM; cost‑based scheduling is not a pillar. Question 6. In work order lifecycle management, which step directly follows “Work Order Approval”? A) Scheduling and resource allocation B) Work execution and data capture C) Closing and documentation D) Identification of the problem Answer: A Explanation: After a work order is approved, the next logical step is to schedule the work and allocate necessary resources.
B) Helical gear C) Bevel gear D) Worm gear Answer: C Explanation: Bevel gears are designed for intersecting shafts, typically at 90°, allowing power transmission between non‑parallel shafts. Question 11. A common wear pattern on a spur gear that indicates excessive sliding is: A) Pitting on the tooth root B) Scoring on the tooth flank C) Chipping at the tip D) Cracking on the hub Answer: B Explanation: Scoring on the tooth flank shows abrasive wear due to sliding contact, common in misaligned or overloaded spur gears. Question 12. When tensioning a V‑belt drive, the correct method is to: A) Increase tension until the belt is taut and audible B) Apply a force equal to 1‑2% of the belt’s linear weight per inch of span C) Use a torque wrench on the pulley shaft D) Set tension based on the belt’s color change Answer: B Explanation: Belt tension is typically set to 1‑2% of the belt’s linear weight per inch of span to ensure proper grip without excessive load. Question 13. Which coupling type allows for angular misalignment while transmitting torque? A) Rigid (flanged) coupling B) Flexible jaw coupling C) Sleeve coupling D) Keyed coupling
Answer: B Explanation: Flexible jaw couplings accommodate angular, axial, and radial misalignments while still transmitting torque. Question 14. Laser alignment of a rotating shaft is primarily used to achieve what tolerance? A) Surface roughness ≤ 0.8 μm B) Parallelism within 0.1 mm over 1 m C) Axial runout ≤ 0.02 mm D) Angular misalignment ≤ 0.02 degrees Answer: D Explanation: Laser alignment tools can measure and correct angular misalignment to within a few hundredths of a degree, ensuring smooth operation. Question 15. Which bearing type is best suited for high‑speed, low‑load applications? A) Spherical roller bearing B) Tapered roller bearing C) Deep‑groove ball bearing D) Plain journal bearing Answer: C Explanation: Deep‑groove ball bearings handle high speeds with relatively low loads due to their low friction design. Question 16. The Stribeck curve is used to illustrate the relationship between: A) Bearing life and load B) Lubricant viscosity and temperature C) Friction coefficient and sliding speed D) Oil contamination level and wear rate Answer: C Explanation: The Stribeck curve plots friction coefficient versus sliding speed, showing boundary, mixed, and hydrodynamic lubrication regimes.
Question 20. A hydraulic accumulator’s primary safety function is to: A) Store excess oil for future use B) Absorb pressure spikes and provide emergency power C) Filter contaminants from the fluid D) Reduce system temperature Answer: B Explanation: Accumulators damp pressure surges and can supply fluid during power loss, protecting components from shock loads. Question 21. Which component of a pneumatic FRL unit removes oil droplets from compressed air? A) Filter B) Regulator C) Lubricator D) Dryer Answer: A Explanation: The filter traps oil and particulates, protecting downstream pneumatic devices. Question 22. A common cause of pneumatic system leaks is: A) Over‑pressurization of the air tank B) Worn PTFE seals in the valve body C) Incorrect oil concentration in the lubricator D) Excessive pipe length Answer: B Explanation: PTFE (Teflon) seals deteriorate over time, leading to air leaks at connections and valve bodies. Question 23. In AC power, the term “power factor” refers to: A) Ratio of real power to apparent power B) Ratio of voltage to current
C) Frequency stability of the supply D) Phase shift between line and neutral Answer: A Explanation: Power factor = real (kW) / apparent (kVA) power, indicating how effectively the current is being converted into useful work. Question 24. When inspecting an induction motor, a high temperature reading on the stator windings most likely indicates: A) Excessive bearing wear B) Poor ventilation or overload C) Shaft misalignment D) Low supply voltage Answer: B Explanation: Overheating of stator windings is typically caused by inadequate cooling, overload, or high ambient temperature. Question 25. A Variable Frequency Drive (VFD) reduces motor speed by: A) Changing the supply voltage amplitude B) Varying the frequency of the AC waveform C) Adding series resistance to the motor circuit D) Adjusting the motor’s pole count Answer: B Explanation: VFDs control motor speed by varying the output frequency, which changes the synchronous speed of the motor. Question 26. Which harmonic mitigation technique is commonly applied to VFD installations? A) Installing a larger motor starter B) Using line‑reactors and AC line filters C) Reducing the motor’s rated voltage D) Increasing the VFD’s switching frequency to > 30 kHz
Explanation: Higher Kp improves response speed but can reduce stability, leading to overshoot or oscillations. Question 30. A Fast Fourier Transform (FFT) spectrum showing a strong peak at 2× line frequency (e.g., 120 Hz in a 60 Hz system) is most indicative of: A) Unbalance B) Misalignment C) Bearing outer race defect D) Electrical supply issue (harmonic) Answer: D Explanation: A 2× line frequency peak is a common electrical harmonic caused by rectification or non‑linear loads. Question 31. Thermographic imaging of an electrical panel reveals a localized hot spot on a bus bar. The most probable cause is: A) Excessive ambient temperature B) Loose connection causing high resistance C) Insufficient airflow in the room D) Over‑rated protective device Answer: B Explanation: Loose or corroded connections increase resistance, generating heat detectable as a hot spot. Question 32. In oil analysis, a high Total Acid Number (TAN) suggests: A) Water contamination B) Oxidative degradation of the oil C) Excessive metal wear particles D) Low viscosity Answer: B Explanation: TAN measures acidic compounds formed during oil oxidation; a high value indicates oil degradation.
Question 33. Ultrasonic testing is most effective for detecting which type of fault in rotating equipment? A) Bearing outer race defect B) High‑frequency vibration caused by imbalance C) Early-stage air or steam leaks D) Temperature rise in motor windings Answer: C Explanation: Ultrasound can detect high‑frequency sound waves generated by small leaks that are invisible to visual inspection. Question 34. The primary purpose of a Lockout/Tagout (LOTO) procedure is to: A) Document maintenance activities for regulatory compliance B) Ensure that equipment is de‑energized and cannot be re‑energized accidentally C) Reduce the number of spare parts required on‑site D) Schedule preventive maintenance tasks Answer: B Explanation: LOTO isolates energy sources and locks them to prevent unexpected start‑up, protecting workers from hazardous energy. Question 35. During confined‑space entry, which atmospheric condition must be continuously monitored? A) Ambient temperature above 40 °C B) Oxygen level between 19.5 % and 23.5 % C) Noise level below 85 dB D) Humidity below 60 % Answer: B Explanation: Safe oxygen concentration is defined as 19.5 %–23.5 %; levels outside this range pose asphyxiation hazards.
B) Total operating time ÷ number of failures C) Total repair time ÷ number of repairs D) Number of preventive tasks ÷ total hours Answer: B Explanation: MTBF = total operating (run) time divided by the number of failures, reflecting reliability. Question 40. If a piece of equipment has an MTTR of 4 hours and an MTBF of 200 hours, its availability (A) is approximately: A) 0. B) 0. C) 0. D) 0. Answer: B Explanation: Availability = MTBF / (MTBF + MTTR) = 200 / (200+4) ≈ 0.980 → 0.95 (rounded to two decimal places). Question 41. Overall Equipment Effectiveness (OEE) is the product of which three factors? A) Reliability, Maintainability, Safety B) Availability, Performance, Quality C) Utilization, Efficiency, Cost D) Production, Downtime, Scrap Answer: B Explanation: OEE = Availability × Performance × Quality, providing a comprehensive equipment productivity metric. Question 42. The “5‑Whys” technique is used primarily to: A) Identify the root cause of a problem by repeated questioning B) Generate a list of possible corrective actions C) Prioritize maintenance tasks based on risk D) Estimate the cost of equipment downtime
Answer: A Explanation: By asking “Why?” five times, investigators drill down to the underlying cause of a failure. Question 43. In a Fishbone (Ishikawa) diagram, which of the following is NOT a typical main category? A) Man B) Method C) Money D) Machine Answer: C Explanation: Classic categories are Man, Machine, Method, Material, Measurement, and Mother‑nature (Environment); “Money” is not a standard branch. Question 44. A corrective action that involves redesigning a component to eliminate a failure mode is classified as: A) Immediate fix B) Work‑around C) Permanent engineering control D) Administrative control Answer: C Explanation: Redesign removes the cause of failure, providing a permanent engineering solution. Question 45. Which of the following lubricants is most appropriate for high‑temperature (≥ 200 °C) applications? A) Mineral oil with EP additives B) Synthetic ester with high flash point C) Grease with lithium complex thickener D) Silicone‑based oil Answer: B
Question 49. In a three‑phase induction motor, what is the purpose of the start capacitor in a single‑phase motor conversion kit? A) Increase starting torque by creating a phase shift B) Reduce motor winding temperature during operation C) Provide a path for ground fault currents D) Balance the three phases during operation Answer: A Explanation: The start capacitor creates a phase‑shifted auxiliary winding, boosting starting torque for single‑phase operation. Question 50. When a PLC I/O module shows “flashing red LED,” the most probable cause is: A) Normal operation B) Communication error with the CPU C) Over‑temperature condition in the module D) Power supply voltage too high Answer: B Explanation: Many PLCs use flashing red LEDs on I/O modules to indicate communication loss or faults with the CPU. Question 51. Which of the following is a common sign of misalignment in rotating equipment observed during vibration analysis? A) Dominant frequency at 2× shaft speed B) High amplitude at 1× shaft speed with sidebands at ± shaft speed C) Random broadband noise D) Low frequency peak at 10 Hz only Answer: B Explanation: Misalignment produces a 1× shaft speed peak with sidebands spaced at the shaft speed, reflecting modulation.
Question 52. A high‑frequency ultrasonic signal detected at a pump’s suction line most likely indicates: A) Cavitation B) Bearing wear C) Air entrainment or leak D) Motor overheating Answer: C Explanation: Ultrasound readily detects air bubbles or small leaks, which produce high‑frequency acoustic emissions. Question 53. Which KPI directly reflects the maintainability of an asset? A) MTBF B) OEE C) MTTR D) Availability Answer: C Explanation: MTTR measures the average time required to repair a failed asset, indicating how maintainable it is. Question 54. During a root‑cause analysis, a “Fault Tree” is primarily used to: A Answer: B Explanation: The fault tree method uses a top‑down logical diagram to trace the combination of events that lead to a system failure. Question 55. In a pneumatic circuit, a 5‑port, 2‑position valve can provide which of the following functions? A
Explanation: Check valves permit flow in one direction only, preventing backflow that could damage pumps or actuators. Question 60. Which of the following is a primary benefit of autonomous maintenance under TPM? A Answer: C Explanation: Autonomous maintenance empowers operators to perform routine inspections, cleaning, and minor adjustments, reducing breakdowns and improving equipment ownership. Question 61. When calibrating a temperature transmitter with a 100 °C span, which two points are essential for a two‑point calibration? A Answer: B Explanation: Zero (0 °C) and full‑scale (100 °C) points verify linearity across the entire measurement range. Question 62. A motor winding temperature rises above its rated limit. Which immediate corrective action is recommended? A Answer: D Explanation: Reducing the motor load or shutting down the motor prevents insulation failure and prolongs motor life. Question 63. In a gear train, “backlash” refers to: A Answer: C
Explanation: Backlash is the clearance between mating gear teeth, allowing for thermal expansion but causing impact if excessive. Question 64. Which lubrication method is most appropriate for high‑speed spindle bearings in CNC machines? A Answer: B Explanation: Automatic oil mist systems provide continuous, low‑viscosity lubrication suitable for high‑speed spindles, reducing friction and heat. Question 65. During a lockout/tagout procedure, the term “zero‑energy state” means: A Answer: D Explanation: Zero‑energy state confirms that all stored energy (electrical, hydraulic, pneumatic, mechanical) has been isolated and dissipated. Question 66. A pneumatic cylinder is moving slower than expected despite correct supply pressure. The most likely cause is: A Answer: C Explanation: Air leaks in the cylinder or tubing reduce effective flow, causing reduced speed even when pressure is adequate. Question 67. In oil analysis, a high “Wear Particle Count” for iron indicates: A Answer: A
