Ramsay Test Mechanical Maintenance 1 — Questions and Answers

Question 1: What type of maintenance is performed on a scheduled basis regardless of equipment condition?

Preventive maintenance (Correct answer)
Corrective maintenance
Predictive maintenance
Breakdown maintenance

Correct answer: Preventive maintenance

Preventive maintenance (PM) is scheduled at regular intervals (time-based or usage-based) regardless of equipment condition. It aims to prevent failures before they occur.

Question 2: What does vibration analysis in predictive maintenance primarily detect?

Imbalance, misalignment, bearing wear, and looseness in rotating machinery (Correct answer)
Oil contamination and viscosity changes
Electrical insulation breakdown
Corrosion on equipment surfaces

Correct answer: Imbalance, misalignment, bearing wear, and looseness in rotating machinery

Vibration analysis measures and interprets vibration signatures to identify mechanical problems in rotating equipment. Different defects (imbalance, misalignment, bearing faults) produce characteristic frequency patterns.

Question 3: A shaft coupling is misaligned. Which type of coupling can best accommodate angular misalignment?

Flexible jaw coupling (Correct answer)
Rigid sleeve coupling
Flange coupling
Compression coupling

Correct answer: Flexible jaw coupling

Flexible jaw (spider) couplings can accommodate small amounts of angular, parallel, and axial misalignment through the elastomeric spider element. Rigid couplings cannot tolerate any misalignment.

Question 4: What is the correct method for installing a bearing onto a shaft using the inner ring press-fit method?

Apply force only to the inner ring using a bearing installation tool or press (Correct answer)
Drive the bearing on by striking the outer ring with a hammer
Heat the bearing and drop it on the shaft
Apply force evenly to both inner and outer rings simultaneously

Correct answer: Apply force only to the inner ring using a bearing installation tool or press

When press-fitting a bearing onto a shaft, force must be applied only to the inner ring (the interference fit surface). Striking the outer ring transmits force through the rolling elements, causing damage.

Question 5: Which lubrication method is best suited for high-speed, lightly loaded bearings?

Oil mist or oil bath lubrication (Correct answer)
Heavy grease packing
Solid lubricant (dry film)
No lubrication

Correct answer: Oil mist or oil bath lubrication

High-speed bearings generate significant heat. Oil mist or oil bath provides continuous, light lubrication with good cooling. Heavy grease packing at high speeds increases friction and heat.

Question 6: What is the primary function of a V-belt drive in mechanical power transmission?

To transmit power between shafts while allowing for speed ratio changes and absorbing shock (Correct answer)
To provide rigid, zero-slip power transmission
To transmit power only between parallel shafts at fixed ratios
To convert rotary motion to linear motion

Correct answer: To transmit power between shafts while allowing for speed ratio changes and absorbing shock

V-belt drives transmit power through friction between the belt and sheave grooves. They allow different speed ratios (by changing sheave sizes), absorb shock loads, and can handle misalignment better than chains.

Question 7: When replacing a hydraulic seal, why is it critical to install the seal in the correct orientation?

Seals have a directional lip that must face the pressure side to function properly (Correct answer)
Orientation affects only cosmetic appearance
All seals are symmetrical and orientation doesn't matter
Incorrect orientation only affects installation ease

Correct answer: Seals have a directional lip that must face the pressure side to function properly

Dynamic seals (lip seals, O-rings in some configurations) have directional lips designed to be energized by system pressure. Reversed installation prevents the lip from sealing against the mating surface, causing immediate leakage.

Question 8: What does 'backlash' refer to in a gear set?

The small clearance between mating gear teeth allowing for lubrication and thermal expansion (Correct answer)
Reverse rotation of a gear when drive direction changes
Gear tooth breakage due to overload
Excessive gear speed causing instability

Correct answer: The small clearance between mating gear teeth allowing for lubrication and thermal expansion

Backlash is the intentional clearance between mating gear teeth. It accommodates lubrication film thickness, thermal expansion, and manufacturing tolerances. Too little causes binding; too much increases noise and wear.

Question 9: A pump is cavitating. Which of the following conditions is the most likely cause?

Insufficient inlet pressure or excessive suction lift causing vapor bubble formation (Correct answer)
Excessive discharge pressure
Over-lubrication of pump bearings
Pump running at too low a speed

Correct answer: Insufficient inlet pressure or excessive suction lift causing vapor bubble formation

Cavitation occurs when local pressure in the pump drops below the fluid's vapor pressure, forming vapor bubbles that collapse violently. Causes include high suction lift, restricted inlet, or fluid temperature too high.

Question 10: What is the purpose of a torque wrench in mechanical maintenance?

To apply a precise, measured amount of torque to fasteners (Correct answer)
To loosen extremely tight fasteners
To measure shaft torque during operation
To tighten fasteners as fast as possible

Correct answer: To apply a precise, measured amount of torque to fasteners

A torque wrench ensures fasteners are tightened to the manufacturer's specified torque value. Under-torquing causes looseness; over-torquing can strip threads, stretch bolts, or crush gaskets.

Question 11: When performing shaft alignment using a dial indicator, a 'soft foot' condition refers to:

One or more machine feet not making full contact with the base, causing distortion when bolted down (Correct answer)
A foot that is corroded and difficult to remove
Excessive vibration in the machine base
Improper use of shims under machine feet

Correct answer: One or more machine feet not making full contact with the base, causing distortion when bolted down

Soft foot occurs when one or more machine mounting feet don't sit flat on the base. When bolted down, it distorts the machine frame, causing misalignment, vibration, and bearing wear. Must be corrected before alignment.

Question 12: What type of bearing is best suited for heavy radial loads at low to moderate speeds?

Cylindrical roller bearing (Correct answer)
Ball bearing
Thrust bearing
Needle bearing

Correct answer: Cylindrical roller bearing

Cylindrical roller bearings have higher radial load capacity than ball bearings of similar size because contact is along a line rather than at a point. They're ideal for heavy radial loads but can't handle thrust loads.

Question 13: In a gear drive, a speed reducer with a 5:1 ratio is connected to a 1,800 RPM motor. What is the output shaft speed?

360 RPM (Correct answer)
9,000 RPM
1,800 RPM
180 RPM

Correct answer: 360 RPM

Output speed = Input speed / Gear ratio = 1,800 / 5 = 360 RPM. A speed reducer reduces shaft speed and proportionally increases torque (at constant power).

Question 14: What is the purpose of a thermal imaging survey in predictive maintenance?

To identify hot spots in electrical connections, bearings, or other components indicating abnormal heat (Correct answer)
To measure ambient temperature in the plant
To verify refrigeration system performance
To check for fire suppression system leaks

Correct answer: To identify hot spots in electrical connections, bearings, or other components indicating abnormal heat

Thermal (infrared) imaging detects abnormal heat patterns caused by loose electrical connections, overloaded circuits, failing bearings, blocked cooling passages, or insulation breakdown before failures occur.

Question 15: Which of the following correctly describes the process of lapping two mating surfaces?

Using an abrasive compound between surfaces to achieve extremely precise, flat mating contact (Correct answer)
Welding two surfaces together for permanent joining
Polishing surfaces with a high-speed grinder
Coating surfaces with an anti-corrosion compound

Correct answer: Using an abrasive compound between surfaces to achieve extremely precise, flat mating contact

Lapping uses fine abrasive compound applied between two mating surfaces which are then rubbed together. This removes high spots and creates precise, leak-free flat-on-flat contact, common on valve seats and precision flanges.

Question 16: A rotating machine is experiencing high axial (thrust) loads. Which bearing type is specifically designed to handle this?

Tapered roller thrust bearing or angular contact ball bearing (Correct answer)
Deep groove ball bearing only
Cylindrical roller bearing
Sleeve (journal) bearing

Correct answer: Tapered roller thrust bearing or angular contact ball bearing

Tapered roller bearings and angular contact ball bearings are designed to handle combinations of radial and axial loads. Pure thrust bearings handle axial loads only. Cylindrical roller bearings handle radial loads only.

Question 17: What does the oil viscosity rating ISO VG 46 indicate?

The oil has a kinematic viscosity of approximately 46 centistokes at 40°C (Correct answer)
The oil has 46% additive content
The oil is suitable only for temperatures below 46°C
The oil has a viscosity index of 46

Correct answer: The oil has a kinematic viscosity of approximately 46 centistokes at 40°C

ISO VG (Viscosity Grade) numbers indicate kinematic viscosity in centistokes (cSt) at 40°C. VG 46 means approximately 46 cSt. Higher numbers = thicker oil, suited for higher loads or temperatures.

Question 18: When replacing a flat gasket on a flanged pipe joint, what is the correct torquing sequence for the bolts?

Tighten bolts in a cross pattern (star sequence) to even compression (Correct answer)
Tighten bolts sequentially around the flange clockwise
Tighten all bolts finger-tight, then fully torque each one in order
Tighten diagonally opposite bolts only

Correct answer: Tighten bolts in a cross pattern (star sequence) to even compression

The cross (star) pattern applies even compression across the gasket, preventing distortion and uneven seating. Bolts are typically torqued in 3 passes: 30%, 70%, then 100% of final torque.

Question 19: What is the primary advantage of predictive maintenance over preventive maintenance?

Maintenance is performed only when actual equipment condition indicates it is needed, reducing unnecessary work (Correct answer)
Equipment is replaced on a fixed schedule regardless of condition
All maintenance is performed during production hours
No specialized equipment or training is required

Correct answer: Maintenance is performed only when actual equipment condition indicates it is needed, reducing unnecessary work

Predictive maintenance uses condition monitoring (vibration, thermography, oil analysis) to schedule maintenance based on actual equipment wear. This avoids both early replacement of good components and unexpected failures.

Question 20: A chain drive is making noise and the chain appears to sag excessively. What maintenance action is required?

Adjust chain tension to specifications and lubricate the chain (Correct answer)
Replace the drive sprockets immediately
Increase motor speed to eliminate sag
Apply heat to shrink the chain

Correct answer: Adjust chain tension to specifications and lubricate the chain

Chain sag indicates wear elongation or improper tension. Adjust the center distance between sprockets to restore proper sag (typically 2-4% of span length). Lubricate to reduce further wear. If elongated beyond 3%, replace the chain.

Question 21: What is the function of a mechanical seal in a centrifugal pump?

To prevent process fluid from leaking along the pump shaft to atmosphere (Correct answer)
To control pump discharge pressure
To balance axial thrust on the pump shaft
To filter debris from the process fluid

Correct answer: To prevent process fluid from leaking along the pump shaft to atmosphere

A mechanical seal provides a leak-free interface between the rotating shaft and stationary pump casing. Two lapped faces (one rotating, one stationary) maintain contact, preventing fluid from leaking out along the shaft.

Question 22: Which tool is used to measure the inside diameter of a bore with high precision?

Bore gauge (internal micrometer) or telescoping gauge with outside micrometer (Correct answer)
Vernier caliper only
Steel ruler
Feeler gauge

Correct answer: Bore gauge (internal micrometer) or telescoping gauge with outside micrometer

Bore gauges and internal micrometers directly measure inside diameters with high accuracy. Telescoping gauges capture the bore diameter and are then measured with an outside micrometer. Calipers are less precise.

Question 23: What does 'run-in' (or break-in) period for new mechanical equipment typically involve?

Operating at reduced load and speed to allow mating surfaces to wear to a compatible fit (Correct answer)
Running at maximum load to identify weaknesses quickly
Stopping the equipment every hour for inspection
Operating in reverse direction to seat bearings

Correct answer: Operating at reduced load and speed to allow mating surfaces to wear to a compatible fit

During run-in, new components operate at reduced loads while surface micro-asperities wear off and mating parts conform to each other. This reduces the risk of early failures and establishes proper bearing clearances.

Question 24: When using a press to remove a bearing from a housing, what must be supported to avoid damage?

The outer ring must be supported when removing a housing-fit bearing (Correct answer)
Only the shaft needs support
No support is needed if force is applied slowly
The inner ring must be supported regardless

Correct answer: The outer ring must be supported when removing a housing-fit bearing

When pressing a bearing out of a housing (outer ring interference fit), the pressing force must be applied to the outer ring. Supporting and pressing the inner ring would force load through the rolling elements, causing damage.

Question 25: A reciprocating compressor requires valve maintenance. What are compressor valves?

Automatic check valves that control gas flow into and out of the cylinder based on pressure differential (Correct answer)
Manually operated ball valves on the suction and discharge lines
Throttle valves controlling compressor speed
Safety relief valves on the discharge side

Correct answer: Automatic check valves that control gas flow into and out of the cylinder based on pressure differential

Compressor valves are automatic, pressure-actuated check valves. Suction valves open when cylinder pressure drops below suction pressure; discharge valves open when cylinder pressure exceeds discharge pressure.

Question 26: What is the purpose of a keyway and key in shaft-to-hub connections?

To transmit torque and prevent relative rotation between the shaft and hub (Correct answer)
To allow the hub to slide axially on the shaft
To prevent axial movement only
To provide electrical grounding between shaft and equipment

Correct answer: To transmit torque and prevent relative rotation between the shaft and hub

A key fits into matching keyways (slots) in both the shaft and hub, creating a positive mechanical connection that transmits torque. The key prevents the hub from rotating on the shaft under load.

Question 27: What is the main advantage of using synthetic lubricating oil over conventional mineral oil in industrial equipment?

Better performance across a wider temperature range, longer service life, and superior oxidation resistance (Correct answer)
Lower initial cost per liter
Availability in more viscosity grades
Better performance only at low temperatures

Correct answer: Better performance across a wider temperature range, longer service life, and superior oxidation resistance

Synthetic oils maintain viscosity across extreme temperatures, resist oxidation and thermal breakdown longer, have lower pour points, and typically last 2-3 times longer than mineral oil before requiring change.

Question 28: A motor coupling shows cracks in the elastomeric (rubber) spider element. What should the maintenance technician do?

Replace the spider element immediately; do not operate with a cracked spider (Correct answer)
Apply adhesive to seal the cracks and continue operation
Monitor the condition and replace at next scheduled shutdown
Increase coupling bolt torque to compensate for the worn element

Correct answer: Replace the spider element immediately; do not operate with a cracked spider

A cracked coupling spider indicates failure. If the spider fails completely during operation, the motor may run away or the load could stop abruptly. Replace immediately to prevent equipment damage or injury.

Question 29: What is the purpose of performing an oil analysis on industrial equipment?

To detect wear metals, contamination, and oil degradation to assess equipment and lubrication condition (Correct answer)
To measure oil flow rate through the system
To determine oil viscosity at operating temperature only
To check for air bubbles in the hydraulic system

Correct answer: To detect wear metals, contamination, and oil degradation to assess equipment and lubrication condition

Oil analysis identifies wear metals (from bearing or gear wear), contamination (water, dirt, fuel), and oil condition (oxidation, viscosity change, additive depletion). It's a key predictive maintenance tool.

Question 30: When performing a cold shaft alignment using dial indicators, what two types of misalignment must be corrected?

Angular misalignment and parallel (offset) misalignment (Correct answer)
Axial and torsional misalignment
Vertical and thermal misalignment
Static and dynamic misalignment

Correct answer: Angular misalignment and parallel (offset) misalignment

Shaft alignment addresses angular misalignment (shafts at an angle to each other) and parallel/offset misalignment (shaft centerlines parallel but offset). Both must be corrected in both vertical and horizontal planes.

Question 31: What is 'galling' in the context of mechanical maintenance?

Severe adhesive wear causing material transfer and surface damage between sliding metal surfaces (Correct answer)
Corrosion on aluminum surfaces
Fatigue cracking in gear teeth
Erosion from high-velocity fluid

Correct answer: Severe adhesive wear causing material transfer and surface damage between sliding metal surfaces

Galling is severe adhesive wear where metal surfaces weld together under high contact pressure and sliding, then tear apart, transferring material from one surface to the other. Common in threaded fasteners and sliding surfaces.

Question 32: What does a lubrication frequency of 'NLGI Grade 2' indicate for a grease?

A medium consistency grease suitable for most general-purpose bearing applications (Correct answer)
The grease changes color at 2°C
The grease must be applied every 2 hours
The grease has 2% molybdenum disulfide additive

Correct answer: A medium consistency grease suitable for most general-purpose bearing applications

NLGI (National Lubricating Grease Institute) grades classify grease consistency. Grade 2 is medium consistency, the most common for general-purpose bearing lubrication. Grades 0-1 are softer; grades 3-6 are stiffer.

Question 33: In a belt drive, what is the consequence of excessive belt tension?

Premature bearing failure due to increased radial load on shaft bearings (Correct answer)
Belt slippage under load
Reduced power transmission efficiency
Increased belt speed

Correct answer: Premature bearing failure due to increased radial load on shaft bearings

Over-tensioned belts impose excessive radial loads on the shaft bearings of both the drive and driven machines, greatly reducing bearing life. Proper tension is critical — usually measured with a tension gauge.

Question 34: What is the purpose of a stuffing box (packing) on a pump, and how does it differ from a mechanical seal?

Packing uses compressed braided material to control leakage; some leakage is intentional for lubrication and cooling (Correct answer)
Packing provides a completely leak-free seal like a mechanical seal
Stuffing boxes are used only in high-pressure applications
Packing requires no adjustment after initial installation

Correct answer: Packing uses compressed braided material to control leakage; some leakage is intentional for lubrication and cooling

Packing (stuffing box) uses rings of braided material compressed by a gland. A small, controlled leakage rate (several drops per minute) is intentional — it lubricates and cools the packing. Mechanical seals are designed for zero leakage.

Question 35: When measuring surface finish, what does Ra indicate?

The arithmetic average roughness — average of all peaks and valleys from the mean surface line (Correct answer)
The maximum peak-to-valley height
The number of surface scratches per square inch
The surface hardness value

Correct answer: The arithmetic average roughness — average of all peaks and valleys from the mean surface line

Ra (roughness average) is the most common surface finish parameter — the arithmetic mean of the absolute deviations from the mean surface line. Lower Ra values indicate smoother surfaces.

Question 36: A centrifugal pump is running but producing no flow. Which of the following is a likely cause?

Air-locked (vapor lock) — air trapped in the impeller (Correct answer)
Motor running in reverse direction
Discharge valve fully open
Pump speed is too high

Correct answer: Air-locked (vapor lock) — air trapped in the impeller

Air lock occurs when air trapped in the pump casing prevents the impeller from creating suction. The pump runs but moves no liquid. The pump must be vented (primed) to remove the air pocket before flow can resume.

Ramsay Test Mechanical Maintenance 1

What type of maintenance is performed on a scheduled basis regardless of equipment condition?