300+ Mechanical Maintenance Engineer Interview Questions and Answers

Hydraulic systems use liquid to transmit power, while pneumatic systems use compressed air.

• Hydraulic systems use incompressible fluids like oil or water, while pneumatic systems use compressed air or gas.

• Hydraulic systems can generate higher forces and are used in heavy machinery like cranes and excavators.

• Pneumatic systems are lighter and more flexible, commonly used in applications like air brakes in vehicles.

• Hydraulic systems are generally more expensive and require more m...read more

To check for pump alignment, use laser alignment tools and follow a step-by-step process.

• Use laser alignment tools to measure and correct misalignment

• Start by checking the pump and motor shafts for parallelism and angularity

• Measure the offset and angular misalignment using the laser alignment tool

• Adjust the pump and motor positions to achieve proper alignment

• Recheck the alignment after adjustments and make necessary corrections

• Ensure the coupling is properly aligned and tight...read more

A six stroke engine is an internal combustion engine that has six strokes in one cycle instead of the usual four strokes.

• The six stroke engine has an additional two strokes, one for heat recovery and another for exhaust.

• The additional strokes improve fuel efficiency and reduce emissions.

• The six stroke engine was first proposed by Bruce Crower in the 1990s.

• Examples of six stroke engines include the Bajulaz engine and the Beare Head engine.

I have handled a wide range of equipment in my role as a Mechanical Maintenance Engineer.

• Pumps and compressors

• Conveyors and material handling equipment

• Boilers and heat exchangers

• HVAC systems

• Generators and power distribution systems

• Machine tools and production equipment

• Hydraulic and pneumatic systems

• Crane and lifting equipment

• Instrumentation and control systems

The main reason for gearbox failure is lack of lubrication, leading to increased friction and wear.

• Lack of proper lubrication causing increased friction

• Contamination of lubricant with dirt or debris

• Overloading the gearbox beyond its capacity

• Improper maintenance and servicing

• Manufacturing defects or poor quality materials

• Incorrect alignment of gears

Maintenance of CPP involves regular inspections, repairs, and upgrades to ensure efficient operation.

• Regularly inspecting and lubricating machinery components

• Performing preventive maintenance tasks to avoid breakdowns

• Replacing worn out parts to prevent failures

• Upgrading equipment to improve efficiency and reliability

• Keeping detailed maintenance records for future reference

Pump efficiency is the ratio of the output power to the input power of a pump.

• Efficiency is important for reducing energy consumption and operating costs.

• It is calculated by dividing the pump's output power by its input power.

• Factors that affect pump efficiency include impeller design, flow rate, and head.

• A more efficient pump will require less energy to achieve the same flow rate and head.

• Regular maintenance and proper sizing can improve pump efficiency.

The number of pressure required to operate a hydraulic equipment depends on the specific equipment and its design.

• The number of pressure required can vary depending on the size and type of hydraulic equipment.

• Some hydraulic equipment may require only one pressure to operate, while others may require multiple pressures for different functions.

• It is important to refer to the equipment's manual or specifications to determine the exact number of pressures required.

The grade of oil used in a hydraulic system depends on the system's requirements and manufacturer recommendations.

• The grade of oil used in a hydraulic system is typically specified by the system manufacturer.

• Common grades of hydraulic oil include ISO VG 32, ISO VG 46, and ISO VG 68.

• The grade of oil chosen should meet the viscosity and performance requirements of the hydraulic system.

• Using the wrong grade of oil can lead to poor system performance and potential damage.

Various machineries are used in a cement plant for different processes.

• Crushers: Used to crush the raw materials like limestone and clay

• Kiln: Used for heating the raw materials to form clinker

• Grinding mills: Used to grind the clinker into fine powder

• Conveyors: Used for transporting materials within the plant

• Packaging machines: Used for packaging the final cement product

The transmission oil capacity for Dozer BD65 is typically around 40-50 liters, and the recommended oil type is usually a high-quality hydraulic transmission oil.

• Typical transmission oil capacity for Dozer BD65 is around 40-50 liters

• Recommended oil type is high-quality hydraulic transmission oil

• Check manufacturer's specifications for exact capacity and oil type

The formula for centrifugal pump head is H = (Q * SG) / (3.14 * D^2 * 2.31)

• Head (H) is calculated using the flow rate (Q), specific gravity (SG), and diameter of the impeller (D)

• The formula is derived from the basic equation for head in a centrifugal pump

• Example: H = (100 gpm * 1.0) / (3.14 * 0.5^2 * 2.31) = 45.75 ft

Cooling towers work on the principle of evaporative cooling to remove heat from a process or building.

• Cooling towers use water as a cooling medium to absorb heat from a process or building.

• The hot water is pumped to the top of the tower and distributed over the fill media.

• As the water flows over the fill media, some of it evaporates, taking away heat and cooling the rest of the water.

• The cooled water is then collected at the bottom of the tower and recirculated back to the pr...read more

I have a strong working ability to provide time completion for mechanical maintenance tasks.

• I prioritize tasks based on their urgency and importance

• I create a schedule and timeline for completing tasks

• I regularly communicate with team members and stakeholders to ensure everyone is aware of progress and any potential delays

• I am flexible and able to adjust timelines as needed

• Example: In my previous role, I was responsible for completing maintenance tasks on a production line. I...read more

The least count of vernier calipers is the smallest measurement that can be read on the scale.

• The least count is typically 0.02 mm for a standard vernier caliper.

• It is determined by dividing the smallest division on the main scale by the total number of divisions on the vernier scale.

• For example, if the main scale has divisions of 1 mm and the vernier scale has 50 divisions, the least count would be 0.02 mm.

Pneumatic cylinders use compressed air while hydraulic cylinders use pressurized fluid to generate force.

• Pneumatic cylinders are lighter and cheaper than hydraulic cylinders.

• Hydraulic cylinders can generate more force than pneumatic cylinders.

• Single-acting, double-acting, and telescoping are common types of hydraulic cylinders.

• Diaphragm, bellows, and rodless are common types of pneumatic cylinders.

I have handled various equipments such as pumps, compressors, valves, motors, and gearboxes in my role as a Mechanical Maintenance Engineer.

• Pumps

• Compressors

• Valves

• Motors

• Gearboxes

TPM stands for Total Productive Maintenance. It is a maintenance strategy aimed at maximizing equipment effectiveness and minimizing downtime.

• TPM involves a proactive approach to maintenance, with a focus on preventing breakdowns and improving overall equipment effectiveness.

• It emphasizes the involvement of all employees in the maintenance process, not just maintenance personnel.

• TPM includes a variety of techniques, such as autonomous maintenance, planned maintenance, and qua...read more

Bearings specifications include load capacity, speed rating, material, and dimensions for optimal performance.

• Load Capacity: Maximum load the bearing can support, e.g., radial and axial loads.

• Speed Rating: Maximum operational speed, e.g., RPM for high-speed applications.

• Material: Common materials include steel, ceramic, and plastic, affecting durability and friction.

• Dimensions: Inner and outer diameter, width, and tolerances for fitting in machinery.

• Lubrication: Type of lubri...read more

Data analysis is crucial for identifying root causes of maintenance issues.

• Recorded data must be analyzed thoroughly to identify patterns and trends.

• Root cause analysis involves identifying the underlying reason for a maintenance issue.

• Data analysis can help prevent future maintenance issues by identifying areas for improvement.

• Examples of recorded data include equipment performance metrics, maintenance logs, and inspection reports.

Two stroke engines have power strokes every revolution, while four stroke engines have power strokes every other revolution.

• Two stroke engines have a simpler design with fewer moving parts compared to four stroke engines

• Two stroke engines require a fuel-oil mixture for lubrication, while four stroke engines have a separate oil reservoir

• Two stroke engines produce more pollution due to incomplete combustion, while four stroke engines are more fuel efficient and environmentally ...read more

The power plant can be based on various cycles such as Rankine, Brayton, or combined cycle.

• The Rankine cycle is commonly used in steam power plants.

• The Brayton cycle is used in gas turbine power plants.

• Combined cycle power plants use both Rankine and Brayton cycles.

• The choice of cycle depends on factors such as fuel type, efficiency, and power output requirements.

K letter is not a standard designation for bearings. It depends on the manufacturer and type of bearing.

• The letter K is not a standard designation for bearings and can vary depending on the manufacturer and type of bearing.

• Bearings are typically designated by a combination of letters and numbers that indicate the type, size, and other specifications.

• Examples of common bearing designations include 6204-2RS, 22216E, and UCFL205-16.

• It is important to consult the manufacturer's s...read more

Types of gears used in motors include spur gears, helical gears, bevel gears, worm gears, and planetary gears.

• Spur gears are the most common type of gear used in motors, with straight teeth cut parallel to the gear's axis.

• Helical gears have angled teeth for smoother and quieter operation compared to spur gears.

• Bevel gears are used to change the direction of rotation between shafts that are not parallel.

• Worm gears consist of a screw (worm) meshing with a gear wheel, providing ...read more

Pickling process is a metal surface treatment method to remove impurities and improve corrosion resistance.

• Pickling is a chemical process used to remove impurities like stains, rust, and scale from metal surfaces.

• It involves immersing the metal in an acidic solution, such as hydrochloric acid or sulfuric acid.

• The process helps to improve the metal's corrosion resistance and prepare it for further treatments like painting or coating.

• Common examples of pickled metals include st...read more

My interested subject is thermodynamics.

• I have a strong interest in studying the behavior of energy and heat transfer.

• I enjoy learning about the laws of thermodynamics and their applications in mechanical systems.

• I find topics like entropy, heat engines, and refrigeration fascinating.

• I have conducted research on improving the efficiency of heat exchangers.

• I have taken advanced courses in thermodynamics during my education.

• I have practical experience in applying thermodynamic ...read more

Angular contact ball bearings are commonly used in CNC spindles due to their ability to handle both radial and axial loads.

• Angular contact ball bearings are used in CNC spindles because they can handle both radial and axial loads efficiently.

• These bearings provide high rigidity and accuracy, which are crucial for CNC machining operations.

• The contact angle of angular contact ball bearings can be adjusted to optimize performance for specific applications.

• Examples of angular con...read more

A caliper is a tool used for measuring the distance between two opposite sides of an object.

• Calipers are commonly used in mechanical engineering for precise measurements.

• There are different types of calipers such as Vernier calipers, dial calipers, and digital calipers.

• Calipers are used in various industries including automotive, aerospace, and manufacturing.

• Famous scientists and engineers like Leonardo da Vinci and Galileo Galilei have worked with calipers in their research ...read more

CNC machines are computer-controlled machines used for precision machining in various industries.

• CNC stands for Computer Numerical Control

• Applications include manufacturing of metal, plastic, wood components with high precision

• Used in industries like aerospace, automotive, electronics, and medical devices

• Can perform complex operations like milling, turning, drilling, and grinding

• Improves efficiency, accuracy, and repeatability in production processes

Types of drilling equipment for rock drilling include rotary drilling rigs, percussion drills, and diamond core drills.

• Rotary drilling rigs use a rotating motion to drill into the rock.

• Percussion drills use a hammering action to break up the rock.

• Diamond core drills use a diamond-tipped bit to cut through the rock.

• Other types of drilling equipment may include auger drills and hydraulic drills.

Preventive maintenance involves regularly scheduled inspections, repairs, and replacements to prevent equipment breakdowns.

• Create a maintenance schedule based on manufacturer recommendations

• Inspect equipment for signs of wear and tear

• Replace worn out parts before they fail

• Lubricate moving parts to reduce friction and wear

• Keep detailed records of maintenance activities

• Train staff on proper maintenance procedures

Mechanical maintenance involves the upkeep and repair of mechanical equipment and machinery.

• Regular inspection and servicing of machinery to prevent breakdowns

• Repairing or replacing faulty parts to ensure optimal performance

• Maintaining accurate records of maintenance activities

• Adhering to safety regulations and guidelines

• Examples include maintaining HVAC systems, repairing engines, and servicing manufacturing equipment

Mechanical maintenance engineers are responsible for ensuring the proper functioning of mechanical equipment and systems.

• Performing regular maintenance and inspections on mechanical equipment

• Troubleshooting and diagnosing mechanical issues

• Repairing or replacing faulty mechanical parts

• Developing and implementing maintenance schedules

• Ensuring compliance with safety regulations

• Collaborating with other engineers and maintenance staff

• Keeping accurate records of maintenance and rep...read more

Brine is a solution of salt in water, commonly used for preserving food and de-icing roads.

• Brine is composed of water and salt

• It is commonly used for pickling vegetables and meats

• Brine is also used for de-icing roads in cold climates

Boiler typically uses demineralized or deionized water to prevent scale buildup and corrosion.

• Demineralized water

• Deionized water

• Reverse osmosis water

• Distilled water

Common problems faced in screw rods include wear and tear, corrosion, misalignment, and jamming.

• Wear and tear due to continuous use can lead to decreased efficiency and eventual failure.

• Corrosion can weaken the screw rod and cause it to break or malfunction.

• Misalignment of the screw rod can result in uneven wear and increased friction.

• Jammed screw rods can be caused by foreign objects or debris getting stuck in the mechanism.

• Lubrication issues can also lead to problems with s...read more

I supervise problems by regularly monitoring equipment performance, conducting inspections, analyzing data, and communicating with team members.

• Regularly monitor equipment performance to identify any abnormalities or signs of potential issues

• Conduct routine inspections to check for wear and tear, leaks, or other issues

• Analyze data from maintenance reports, equipment logs, and performance metrics to detect patterns or trends indicating a problem

• Communicate with team members to...read more

I have faced various hydraulic breakdowns in my career as a Mechanical Maintenance Engineer.

• One common hydraulic breakdown is a leak in the hydraulic system, which can be caused by worn-out seals or damaged hoses.

• Another issue is a hydraulic pump failure, which can occur due to excessive wear and tear or lack of proper maintenance.

• Clogged or blocked hydraulic filters can also lead to breakdowns, as they restrict the flow of hydraulic fluid.

• Problems with hydraulic valves, such...read more

Engine parts work together to convert fuel into mechanical energy, powering vehicles and machinery.

• Cylinder: Houses the piston and is where combustion occurs.

• Piston: Moves up and down within the cylinder, converting pressure into mechanical work.

• Crankshaft: Transforms the linear motion of the piston into rotational motion.

• Camshaft: Controls the opening and closing of the engine's valves.

• Valves: Regulate the intake of air/fuel and exhaust of combustion gases.

• Spark Plug: Ignite...read more

Thermal power plants generate electricity by converting heat energy into electrical energy.

• Fuel (coal, oil, gas) is burned to produce heat

• Heat is used to boil water and produce steam

• Steam drives a turbine connected to a generator, producing electricity

• Cooling water is used to condense the steam back into water for reuse

• Electricity is then transmitted through power lines to consumers

The type of steam produced by a boiler depends on the pressure and temperature of the water being heated.

• Low-pressure steam is typically used for heating and domestic hot water.

• High-pressure steam is used for power generation and industrial processes.

• Superheated steam is used in turbines to generate electricity.

• Saturated steam is used in cooking and sterilization processes.

• The type of steam produced can also depend on the type of fuel being burned in the boiler.

Various types of oils can be used in hydraulic systems, including mineral oil, synthetic oil, and biodegradable oil.

• Mineral oil is commonly used in hydraulic systems due to its cost-effectiveness and compatibility with most systems.

• Synthetic oil is used in high-performance hydraulic systems for better temperature resistance and longevity.

• Biodegradable oil is used in environmentally sensitive areas to reduce the impact of potential leaks or spills.

Various types of valves are used in hydraulic systems, including directional control valves, pressure control valves, flow control valves, and check valves.

• Directional control valves are used to control the direction of fluid flow in the system.

• Pressure control valves are used to regulate the pressure within the system.

• Flow control valves are used to control the flow rate of the fluid in the system.

• Check valves are used to prevent backflow in the system.

• Examples include ball ...read more

Yes, generator alignment is crucial for efficient operation and preventing damage.

• Generator alignment ensures that the rotating parts are properly positioned to prevent vibration and wear

• Improper alignment can lead to increased maintenance costs and reduced efficiency

• Alignment methods include laser alignment, dial indicators, and alignment jigs

• Regular alignment checks should be performed to ensure optimal performance

• Example: Misaligned generator shafts can cause bearing failu...read more

Seal numbers can be found on the seal itself or in the equipment manual.

• Check the seal itself for any visible numbers or markings.

• Refer to the equipment manual for information on the seal.

• Contact the manufacturer or supplier for assistance in identifying the seal number.

The pH scale ranges from 0 to 14, with 7 being neutral, below 7 acidic, and above 7 alkaline.

• pH range is from 0 to 14

• 7 is considered neutral

• Below 7 is acidic

• Above 7 is alkaline

• Examples: Lemon juice has a pH of around 2, pure water has a pH of 7, and baking soda has a pH of around 9

A compressor works by increasing the pressure of a gas to compress it into a smaller volume.

• Compressors use a motor to drive a piston or rotor that compresses the gas.

• The compressed gas is then stored in a tank or released for use in various applications.

• Common types of compressors include reciprocating, rotary screw, and centrifugal compressors.