NYC Machinery Maintainer Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. A technician is troubleshooting a centrifugal pump that has lost prime
after a maintenance shutdown. Which of the following is the most
likely cause preventing the pump from self-priming?
A. Excessive motor voltage
B. Air leakage in the suction line
C. Increased discharge pressure
D. Oversized impeller clearance
B
Air entering the suction line prevents the creation of the necessary vacuum
for priming, which is essential for proper centrifugal pump operation,
making air leakage the most common cause of loss of prime.
2. A three-phase motor is running in reverse direction after replacement.
What is the most appropriate corrective action?
A. Replace the starter coil
B. Swap any two incoming power leads
C. Increase circuit breaker rating
D. Reduce motor load
B
,Reversing any two of the three phase leads changes the phase rotation,
which reverses the motor direction without altering equipment or internal
components.
3. A hydraulic system exhibits slow actuator movement and overheating.
What is the most probable cause?
A. Excessive fluid viscosity
B. Relief valve stuck open
C. Low reservoir temperature
D. Oversized hydraulic pump
B
A relief valve stuck open causes continuous fluid bypass, reducing system
pressure and generating heat due to energy loss, leading to slow actuator
response.
4. Which tool is most appropriate for accurately measuring internal bore
diameters of a worn cylinder sleeve?
A. Outside micrometer
B. Dial bore gauge
C. Feeler gauge
D. Vernier caliper only
B
A dial bore gauge is specifically designed to measure internal diameters
with high precision, especially useful for detecting taper and out-of-round
conditions.
5. A belt-driven system shows excessive belt wear and slippage. Which
condition is most likely responsible?
A. Excessive pulley alignment accuracy
B. Over-tensioned belt condition
C. Insufficient belt tension
,D. Increased lubrication of pulleys
C
Insufficient belt tension reduces frictional grip between belt and pulley,
causing slippage, heat buildup, and accelerated wear.
6. What is the primary function of a check valve in a piping system?
A. Regulate system pressure
B. Allow flow in both directions
C. Prevent reverse flow
D. Increase fluid velocity
C
A check valve is designed to permit flow in only one direction, preventing
backflow that could damage equipment or disrupt system operation.
7. An electric motor draws significantly higher current than its rated
value under normal load. Which condition is most likely?
A. Under-voltage supply
B. Decreased mechanical load
C. Over-lubricated bearings
D. Increased insulation resistance
A
Under-voltage supply causes the motor to draw higher current to maintain
torque output, often leading to overheating and inefficiency.
8. Which type of bearing is most suitable for handling both radial and
axial loads in high-speed machinery?
A. Plain sleeve bearing
B. Ball thrust bearing
C. Tapered roller bearing
D. Needle bearing
C
, Tapered roller bearings are engineered to support combined radial and
axial loads efficiently, making them ideal for high-speed and heavy-duty
applications.
9. A steam trap is installed in a condensate return line. What is its
primary purpose?
A. Increase steam pressure
B. Remove condensate while retaining steam
C. Regulate boiler temperature
D. Compress return steam
B
Steam traps discharge condensate and non-condensable gases while
preventing live steam loss, ensuring system efficiency.
10. Which condition would most likely cause cavitation in a pump?
A. Excessive discharge pressure
B. Insufficient suction head
C. High fluid viscosity
D. Oversized discharge pipe
B
Cavitation occurs when suction pressure drops below vapor pressure,
causing vapor bubble formation that collapses and damages pump
components.
11. What is the main purpose of lockout/tagout (LOTO) procedures?
A. Improve equipment efficiency
B. Prevent unauthorized machine use during maintenance
C. Reduce electrical resistance
D. Increase hydraulic pressure
B
Practice Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. A technician is troubleshooting a centrifugal pump that has lost prime
after a maintenance shutdown. Which of the following is the most
likely cause preventing the pump from self-priming?
A. Excessive motor voltage
B. Air leakage in the suction line
C. Increased discharge pressure
D. Oversized impeller clearance
B
Air entering the suction line prevents the creation of the necessary vacuum
for priming, which is essential for proper centrifugal pump operation,
making air leakage the most common cause of loss of prime.
2. A three-phase motor is running in reverse direction after replacement.
What is the most appropriate corrective action?
A. Replace the starter coil
B. Swap any two incoming power leads
C. Increase circuit breaker rating
D. Reduce motor load
B
,Reversing any two of the three phase leads changes the phase rotation,
which reverses the motor direction without altering equipment or internal
components.
3. A hydraulic system exhibits slow actuator movement and overheating.
What is the most probable cause?
A. Excessive fluid viscosity
B. Relief valve stuck open
C. Low reservoir temperature
D. Oversized hydraulic pump
B
A relief valve stuck open causes continuous fluid bypass, reducing system
pressure and generating heat due to energy loss, leading to slow actuator
response.
4. Which tool is most appropriate for accurately measuring internal bore
diameters of a worn cylinder sleeve?
A. Outside micrometer
B. Dial bore gauge
C. Feeler gauge
D. Vernier caliper only
B
A dial bore gauge is specifically designed to measure internal diameters
with high precision, especially useful for detecting taper and out-of-round
conditions.
5. A belt-driven system shows excessive belt wear and slippage. Which
condition is most likely responsible?
A. Excessive pulley alignment accuracy
B. Over-tensioned belt condition
C. Insufficient belt tension
,D. Increased lubrication of pulleys
C
Insufficient belt tension reduces frictional grip between belt and pulley,
causing slippage, heat buildup, and accelerated wear.
6. What is the primary function of a check valve in a piping system?
A. Regulate system pressure
B. Allow flow in both directions
C. Prevent reverse flow
D. Increase fluid velocity
C
A check valve is designed to permit flow in only one direction, preventing
backflow that could damage equipment or disrupt system operation.
7. An electric motor draws significantly higher current than its rated
value under normal load. Which condition is most likely?
A. Under-voltage supply
B. Decreased mechanical load
C. Over-lubricated bearings
D. Increased insulation resistance
A
Under-voltage supply causes the motor to draw higher current to maintain
torque output, often leading to overheating and inefficiency.
8. Which type of bearing is most suitable for handling both radial and
axial loads in high-speed machinery?
A. Plain sleeve bearing
B. Ball thrust bearing
C. Tapered roller bearing
D. Needle bearing
C
, Tapered roller bearings are engineered to support combined radial and
axial loads efficiently, making them ideal for high-speed and heavy-duty
applications.
9. A steam trap is installed in a condensate return line. What is its
primary purpose?
A. Increase steam pressure
B. Remove condensate while retaining steam
C. Regulate boiler temperature
D. Compress return steam
B
Steam traps discharge condensate and non-condensable gases while
preventing live steam loss, ensuring system efficiency.
10. Which condition would most likely cause cavitation in a pump?
A. Excessive discharge pressure
B. Insufficient suction head
C. High fluid viscosity
D. Oversized discharge pipe
B
Cavitation occurs when suction pressure drops below vapor pressure,
causing vapor bubble formation that collapses and damages pump
components.
11. What is the main purpose of lockout/tagout (LOTO) procedures?
A. Improve equipment efficiency
B. Prevent unauthorized machine use during maintenance
C. Reduce electrical resistance
D. Increase hydraulic pressure
B
