CWEA MECHANICAL TECHNOLOGIST EXAM – QUESTIONS AND
ANSWERS | VERIFIED AND WELL DETAILED ANSWERS | PLUS
RATIONALES | A+ MATERIAL | NEWEST UPDATE
Core Domains: *
1. Pumps, Hydraulics, and Fluid Mechanics *
2. Preventative and Corrective Maintenance *
3. Alignment, Vibration Analysis, and Balancing *
4. Rigging, Hoisting, and Material Handling *
5. Lubrication Principles and Tribology *
6. Valves, Actuators, and Piping Systems *
, 7. Safety, OSHA Regulations, and Confined Space Entry
8. Shop Math, Blueprints, and Technical Drawings *
Introduction: *
This examination is designed to rigorously evaluate the technic
Question 1: What is the primary cause of cavitation in a centrifugal
wastewater pump?
A. Operating the pump at speeds exceeding the motor rating
🟢 B. Vapor pressure of the liquid dropping below the suction pressure
C. Excessive bearing clearance in the outboard housing
D. Misalignment between the pump shaft and motor coupling
🔴 Explanation: Cavitation occurs when the local pressure inside the
pump drops below the vapor pressure of the liquid being pumped, forming
vapor bubbles that subsequently collapse with destructive force.
Question 2: When performing a precision shaft alignment using a dial
indicator, what term describes the angular deviation between the
centerlines of two shafts?
A. Radial offset
🟢 B. Angular misalignment
C. Axial float
D. Runout
🔴 Explanation: Angular misalignment exists when the centerlines of two
shafts are not parallel and intersect at an angle, whereas radial offset
refers to parallel shafts that are displaced radially.
, Question 3: Which type of positive displacement pump is commonly used
for metering polymer solutions in wastewater treatment plants?
A. Centrifugal pump
B. Axial flow pump
🟢 C. Diaphragm pump
D. Submersible drainage pump
🔴 Explanation: Diaphragm pumps provide precise volumetric flow
control and excellent chemical resistance, making them ideal for metering
polymers and other treatment chemicals.
Question 4: According to OSHA standards, what is the minimum
clearance distance required when operating heavy machinery or cranes
near energized high-voltage power lines up to 50 kV?
A. 5 feet
🟢 B. 10 feet
C. 15 feet
D. 20 feet
🔴 Explanation: OSHA regulations specify a minimum clearance of 10
feet for overhead power lines up to 50 kV to protect workers and
equipment from electrical contact hazards.
Question 5: Which lubrication failure mode is characterized by
microscopic surface fatigue pitting resulting from repeated high-contact
stresses?
A. Scoring
B. Abrasive wear
🟢 C. Spalling
D. Corrosion
🔴 Explanation: Spalling is a fatigue failure mode where small pieces of
metal break away from the raceways or rolling elements of a bearing due
to cyclic sub-surface shear stresses.
Question 6: What is the primary function of a mechanical seal in a
centrifugal wastewater pump?
A. To support radial shaft loads and reduce friction
B. To prevent shaft deflection under high-torque conditions
🟢 C. To prevent the leakage of process fluid along the rotating shaft into
the atmosphere
D. To increase discharge head and overall hydraulic efficiency
🔴 Explanation: A mechanical seal creates a tight, running interface
between a rotating shaft and a stationary pump housing to prevent
process fluid leakage.
ANSWERS | VERIFIED AND WELL DETAILED ANSWERS | PLUS
RATIONALES | A+ MATERIAL | NEWEST UPDATE
Core Domains: *
1. Pumps, Hydraulics, and Fluid Mechanics *
2. Preventative and Corrective Maintenance *
3. Alignment, Vibration Analysis, and Balancing *
4. Rigging, Hoisting, and Material Handling *
5. Lubrication Principles and Tribology *
6. Valves, Actuators, and Piping Systems *
, 7. Safety, OSHA Regulations, and Confined Space Entry
8. Shop Math, Blueprints, and Technical Drawings *
Introduction: *
This examination is designed to rigorously evaluate the technic
Question 1: What is the primary cause of cavitation in a centrifugal
wastewater pump?
A. Operating the pump at speeds exceeding the motor rating
🟢 B. Vapor pressure of the liquid dropping below the suction pressure
C. Excessive bearing clearance in the outboard housing
D. Misalignment between the pump shaft and motor coupling
🔴 Explanation: Cavitation occurs when the local pressure inside the
pump drops below the vapor pressure of the liquid being pumped, forming
vapor bubbles that subsequently collapse with destructive force.
Question 2: When performing a precision shaft alignment using a dial
indicator, what term describes the angular deviation between the
centerlines of two shafts?
A. Radial offset
🟢 B. Angular misalignment
C. Axial float
D. Runout
🔴 Explanation: Angular misalignment exists when the centerlines of two
shafts are not parallel and intersect at an angle, whereas radial offset
refers to parallel shafts that are displaced radially.
, Question 3: Which type of positive displacement pump is commonly used
for metering polymer solutions in wastewater treatment plants?
A. Centrifugal pump
B. Axial flow pump
🟢 C. Diaphragm pump
D. Submersible drainage pump
🔴 Explanation: Diaphragm pumps provide precise volumetric flow
control and excellent chemical resistance, making them ideal for metering
polymers and other treatment chemicals.
Question 4: According to OSHA standards, what is the minimum
clearance distance required when operating heavy machinery or cranes
near energized high-voltage power lines up to 50 kV?
A. 5 feet
🟢 B. 10 feet
C. 15 feet
D. 20 feet
🔴 Explanation: OSHA regulations specify a minimum clearance of 10
feet for overhead power lines up to 50 kV to protect workers and
equipment from electrical contact hazards.
Question 5: Which lubrication failure mode is characterized by
microscopic surface fatigue pitting resulting from repeated high-contact
stresses?
A. Scoring
B. Abrasive wear
🟢 C. Spalling
D. Corrosion
🔴 Explanation: Spalling is a fatigue failure mode where small pieces of
metal break away from the raceways or rolling elements of a bearing due
to cyclic sub-surface shear stresses.
Question 6: What is the primary function of a mechanical seal in a
centrifugal wastewater pump?
A. To support radial shaft loads and reduce friction
B. To prevent shaft deflection under high-torque conditions
🟢 C. To prevent the leakage of process fluid along the rotating shaft into
the atmosphere
D. To increase discharge head and overall hydraulic efficiency
🔴 Explanation: A mechanical seal creates a tight, running interface
between a rotating shaft and a stationary pump housing to prevent
process fluid leakage.
