700+ Maintenance Engineer Interview Questions and Answers

The types of modules used with PLC include input modules, output modules, communication modules, analog modules, and specialty modules.

• Input modules are used to receive signals from sensors and other devices.

• Output modules are used to send signals to actuators and other devices.

• Communication modules enable PLCs to communicate with other devices or systems.

• Analog modules are used to process and control analog signals.

• Specialty modules are designed for specific functions, such ...read more

I have a strong understanding of hydraulic equipment and their functions.

• I have experience in maintaining and repairing hydraulic pumps, valves, and cylinders.

• I am familiar with the different types of hydraulic systems and their applications.

• I have knowledge of hydraulic fluid properties and their effects on equipment performance.

• I am skilled in troubleshooting hydraulic equipment issues and finding solutions.

• I stay up-to-date with industry advancements and new technologies i...read more

I chose the maintenance line because I enjoy problem-solving and working with my hands.

• I have always been interested in fixing things and finding solutions to technical problems.

• I enjoy the satisfaction of seeing a machine or system running smoothly after I have repaired or maintained it.

• Maintenance work allows me to constantly learn and stay updated with new technologies and equipment.

• I am detail-oriented and enjoy the process of troubleshooting and diagnosing issues.

• I have ...read more

Maintenance activities involve the regular inspection, repair, and upkeep of equipment and facilities to ensure their optimal functioning.

• Maintenance activities include preventive maintenance, corrective maintenance, and predictive maintenance.

• Preventive maintenance involves scheduled inspections and maintenance tasks to prevent equipment breakdowns.

• Corrective maintenance involves repairing equipment after a breakdown or failure.

• Predictive maintenance uses data analysis and m...read more

Answering questions related to Maintenance Engineer interview.

• Types of boilers include fire tube, water tube, and electric boilers.

• Chilling plant capacity can be calculated by multiplying the flow rate by the temperature difference.

• Colour coding in industry is used to identify pipes, wires, and equipment based on their function or contents.

• Schedule maintenance is planned maintenance that is performed at regular intervals, while preventive maintenance is maintenance that is pe...read more

Bearings are used to reduce friction between two moving parts. There are different types of bearings.

• Plain bearings

• Rolling element bearings

• Jewel bearings

• Fluid bearings

• Magnetic bearings

Yes, I am familiar with Digital Multimeter. It is used to measure voltage, current, and resistance in electronic components.

• Set the multimeter to the appropriate setting for the component you are testing (voltage, current, or resistance)

• Connect the red probe to the positive terminal and the black probe to the negative terminal of the component

• Read the measurement displayed on the multimeter screen

• For HV diode: Set the multimeter to diode testing mode, place the red probe on t...read more

There are mainly two types of motors used in elevators: AC and DC motors.

• AC motors are commonly used in high-rise buildings and have a longer lifespan.

• DC motors are used in low-rise buildings and are more energy-efficient.

• AC motors are more expensive than DC motors.

• AC motors have a higher starting torque than DC motors.

• Examples of AC motors used in elevators include induction motors and synchronous motors.

• Examples of DC motors used in elevators include shunt-wound motors and ...read more

Parameters considered while building a boiler

• Boiler type and size

• Fuel type and availability

• Operating pressure and temperature

• Efficiency and emissions

• Safety features and regulations

• Maintenance requirements

• Cost and budget constraints

Calculating cooling tower TR, boiler efficiency, and types and capacity of chilling plant compressors.

• Cooling tower TR can be calculated using the formula: TR = (500 x GPM x Delta T)/12000

• Boiler efficiency can be calculated using the formula: Efficiency = (Output/Input) x 100

• Types of compressors include reciprocating, rotary screw, centrifugal, and scroll.

• Capacity of compressors is measured in tons of refrigeration (TR) or in cubic feet per minute (CFM).

• Chilling plant compres...read more

Overview of VFD, PLC, transformers, sensors, and rectifiers in maintenance engineering.

• VFD (Variable Frequency Drive) controls motor speed by varying frequency and voltage.

• PLC (Programmable Logic Controller) automates processes; models include Siemens S7, Allen-Bradley.

• Transformers transfer electrical energy between circuits, changing voltage levels.

• Sensors detect physical properties; types include temperature, pressure, and proximity sensors.

• Rectifiers convert AC to DC; they...read more

SS 304 and SS 316 are both stainless steel alloys, but they differ in their composition and properties.

• SS 304 contains 18% chromium and 8% nickel, while SS 316 contains 16% chromium, 10% nickel, and 2% molybdenum.

• SS 316 has better corrosion resistance than SS 304, especially in environments with chlorides or acids.

• SS 316 is more suitable for marine applications or those involving exposure to harsh chemicals.

• SS 304 is generally more affordable and widely used in applications w...read more

Power factor is the ratio of real power to apparent power in an electrical system. It needs to be maintained for efficient power transfer and to avoid penalties from utility companies.

• Power factor impacts the efficiency of power transfer in electrical systems

• Low power factor can result in higher energy costs and penalties from utility companies

• It affects the quality of power supply and can lead to voltage drops and equipment overheating

• Power factor can be improved by using po...read more

Blowdown of cooling tower can be calculated using cycles of concentration. Maintenance practices include regular cleaning, inspection, and water treatment. Cooling tower capacity can be calculated based on heat load and design parameters.

• Calculate blowdown using cycles of concentration formula: Blowdown = Evaporation Loss / (Cycles of Concentration - 1)

• Maintenance practices include regular cleaning of cooling tower fill, drift eliminators, and basin, inspection of mechanical ...read more

A three-axis robot is a robotic system that operates in three dimensions, allowing it to move and manipulate objects in a wide range of directions.

• A three-axis robot typically consists of three linear axes, each capable of independent movement along a specific axis (X, Y, and Z).

• The X-axis controls horizontal movement, the Y-axis controls vertical movement, and the Z-axis controls depth or forward/backward movement.

• By combining movements along these three axes, the robot can ...read more

Preventive maintenance in automation industry involves regular inspections, cleaning, lubrication, and replacement of parts.

• Regularly inspecting equipment to identify potential issues before they become major problems

• Cleaning and lubricating machinery to prevent wear and tear

• Replacing worn or damaged parts before they fail

• Using predictive maintenance techniques such as vibration analysis and thermography to detect potential problems

• Creating a maintenance schedule and sticking...read more

Elevator is a vertical transportation device that moves people or goods between floors of a building.

• Elevators are powered by electric motors that drive traction cables or hydraulic pistons.

• They have safety features such as emergency brakes, overspeed governors, and door interlocks.

• Elevators can be controlled by various systems such as relay logic, microprocessors, or destination dispatch.

• Modern elevators also have features such as touchscreens, voice announcements, and desti...read more

AC drives control the speed of AC motors by varying the frequency of the electrical supply.

• AC drives use power electronics to convert AC power to DC power and then back to AC power at the desired frequency.

• Different types of starters include direct-on-line (DOL), star-delta, soft starters, and variable frequency drives (VFDs).

• DOL starters provide full voltage to the motor, while star-delta starters reduce the voltage during starting to reduce current and torque.

• Soft starters ...read more

Use a phase failure relay to protect the motor.

• Install a phase failure relay to detect the absence of a phase and disconnect the motor from the supply.

• Check the motor's wiring and connections to ensure they are correct and secure.

• If the motor is already running, shut it down immediately to prevent damage.

• Consult with an electrician to determine the cause of the phase failure and resolve the issue.

• Consider using a backup power source or generator to prevent future phase failur...read more

There are different types of hydraulic oils used in hydraulic machines depending on the application and operating conditions.

• Mineral-based hydraulic oil is the most common type used in hydraulic machines.

• Synthetic hydraulic oil is used in high-performance applications where extreme temperatures and pressures are encountered.

• Biodegradable hydraulic oil is used in environmentally sensitive areas.

• Fire-resistant hydraulic oil is used in applications where there is a risk of fire....read more

Proximity sensors are devices that detect the presence or absence of an object using electromagnetic fields, light, or sound.

• Proximity sensors can be categorized into inductive, capacitive, ultrasonic, and photoelectric sensors.

• Inductive sensors detect metal objects using electromagnetic fields.

• Capacitive sensors detect non-metal objects by measuring changes in capacitance.

• Ultrasonic sensors use sound waves to detect objects within a certain range.

• Photoelectric sensors use li...read more

Pipe size for given pressure of steam can be calculated using the formula for flow rate and velocity.

• Calculate the required flow rate of steam based on the application and process requirements.

• Determine the velocity of steam based on the flow rate and pipe size.

• Use the Darcy-Weisbach equation or other relevant formulas to calculate the pressure drop in the pipe.

• Select a pipe size that can handle the required flow rate and pressure drop without exceeding the maximum allowable ...read more

Gate valves and ball valves are two common types of valves used in industrial applications.

• Gate valves have a sliding gate that controls the flow of fluid through the valve.

• Ball valves have a rotating ball with a hole in the middle that controls the flow of fluid through the valve.

• Gate valves are typically used for on/off control of fluid flow, while ball valves are used for throttling and control applications.

• Gate valves are often larger and heavier than ball valves, and req...read more

A diode is an electronic component that allows current to flow in one direction only.

• A diode has two terminals: an anode and a cathode.

• To check if a diode is true or false, set the multimeter to the diode test mode.

• Connect the red probe to the anode and the black probe to the cathode.

• If the diode is good, the multimeter will show a voltage drop of around 0.6 to 0.7 volts.

• If the diode is bad, the multimeter will show no voltage drop or a very high voltage drop.

• Reverse the prob...read more

The glass thickness of msgl reactor varies depending on the manufacturer and model.

• The glass thickness can range from 5mm to 20mm.

• It is important to consult the manufacturer's specifications for the specific reactor in question.

• Factors such as pressure and temperature can also affect the required glass thickness.

• Regular inspections and maintenance should be conducted to ensure the integrity of the glass lining.

Cope and drag are the two halves of a mold used in casting processes to create a cavity for the molten metal.

• Cope is the top half of the mold, while drag is the bottom half.

• The cope and drag are typically made from sand and are used to create a cavity in which the molten metal is poured.

• After the metal has solidified, the cope and drag are separated to reveal the casting.

Methods for measuring with a micrometer and a vernier caliper

• For micrometer: Close the jaws gently around the object being measured, read the measurement from the scale, and add any additional measurements from the thimble.

• For vernier caliper: Close the jaws around the object, read the main scale measurement where the zero mark on the vernier scale aligns, then add the vernier scale measurement for precision.

• Ensure the objects being measured are clean and free from debris to ...read more