200+ Mechanical Maintenance Engineer Interview Questions and Answers

Questions related to mechanical engineering concepts such as valves, couplings, pumps, gears, and measurement tools.

• Valve is a device used to control the flow of fluids. Types include gate, globe, ball, and butterfly valves.

• Coupling is a device used to connect two shafts together. Types include rigid, flexible, and fluid couplings.

• Pump is a device used to move fluids. Types include centrifugal, positive displacement, and axial flow pumps.

• Backlash is the amount of play between...read more

Questions related to types of pumps, casing, plant process, maintenance, centrifuge pusher, mechanical seals, boiler and thermic fluid heater, pump efficiency, head measurement, and alignment method.

• Types of pumps include centrifugal, reciprocating, and rotary pumps

• Types of casing include volute, diffuser, and multistage casing

• Plant process involves the steps and equipment used in a manufacturing process

• Major maintenance attend in previous organization periods may include pum...read more

Mechanical seals are used to prevent leakage in rotating equipment. They can be classified into various types based on their design and application.

• Types of mechanical seals include pusher seals, non-pusher seals, cartridge seals, and split seals.

• Pusher seals use springs to maintain contact between the seal faces.

• Non-pusher seals rely on the pressure of the fluid being sealed to maintain contact.

• Cartridge seals are pre-assembled units that can be easily replaced.

• Split seals a...read more

The thickness of the wire rope used in a 15-ton E.O.T crane depends on various factors.

• The thickness of the wire rope is determined by the load capacity and safety factors.

• The type of wire rope, such as 6x19 or 6x37, also affects the thickness.

• The diameter of the wire rope can range from 10mm to 32mm or more.

• Consulting the crane manufacturer's specifications or engineering standards is necessary to determine the exact thickness.

There are various types of seals used in hydraulics and pneumatic systems.

• O-rings: commonly used in both hydraulic and pneumatic systems

• Piston seals: used to prevent fluid leakage in hydraulic systems

• Rod seals: used to prevent fluid leakage in hydraulic systems

• Wiper seals: used to prevent contaminants from entering hydraulic or pneumatic systems

• Rotary seals: used in rotary applications to prevent fluid leakage

• V-ring seals: used in dynamic axial sealing applications

• Gaskets: us...read more

There are various types of hydraulic valves used in different applications.

• Directional control valves: used to control the direction of fluid flow in a hydraulic system.

• Pressure control valves: used to regulate the pressure of the hydraulic fluid.

• Flow control valves: used to control the flow rate of the hydraulic fluid.

• Check valves: used to allow fluid flow in one direction and prevent backflow.

• Relief valves: used to protect the hydraulic system from excessive pressure.

• Propor...read more

The size of the bolt for a drill bit or hole depends on the diameter of the hole.

• The bolt size is typically determined by the diameter of the hole.

• For smaller holes, such as those made by small drill bits, smaller bolts like M4 or M5 may be used.

• For larger holes, such as those made by larger drill bits, larger bolts like M10 or M12 may be used.

• The specific bolt size may also depend on the application and the required strength.

• It is important to consult bolt size charts or eng...read more

The most effective way to gather user and system requirements is through direct communication and collaboration.

• Engage with stakeholders to understand their needs and preferences

• Utilize surveys, interviews, and workshops to gather feedback

• Document requirements clearly and prioritize them based on importance

• Use prototyping and mockups to visualize the final product

• Regularly communicate and update stakeholders on the progress

The name used for two travelling EOT cranes not touching each other during working time is 'tandem operation'.

• Tandem operation is a technique used in crane operations where two cranes work together in synchronization.

• The cranes are controlled by a single operator and operate in close proximity without touching each other.

• Tandem operation allows for increased lifting capacity and flexibility in handling heavy loads.

• It requires precise coordination and communication between the...read more

Overhauling a pump involves disassembling, inspecting, repairing/replacing parts, and reassembling it.

• Begin by disconnecting the pump from the power source and draining any remaining fluid.

• Disassemble the pump and inspect all parts for wear and damage.

• Repair or replace any damaged parts, such as bearings or seals.

• Clean all parts thoroughly and reassemble the pump.

• Test the pump to ensure it is functioning properly before putting it back into service.

Hydraulic circuits and mechanical work are integral parts of mechanical maintenance engineering. I chose this field due to my passion for problem-solving and interest in machinery.

• Hydraulic circuits involve the use of fluids to transmit power and control machinery

• Mechanical work involves the use of physical force and motion to operate machinery

• As a mechanical maintenance engineer, I am responsible for ensuring the proper functioning of machinery and equipment

• I chose this fiel...read more

Electricity is produced in a generator through electromagnetic induction. Faraday's law of electromagnetic induction explains this process.

• Electricity is produced in a generator through the process of electromagnetic induction.

• When a conductor is moved through a magnetic field, or a magnetic field is moved around a conductor, it creates an electric current.

• This current is then collected and converted into usable electricity.

• Faraday's law of electromagnetic induction states th...read more

I am most familiar with C++ and Python programming languages.

• C++

• Python

Boilers are vessels that generate steam by heating water. There are various types of boilers with different working procedures and safety norms.

• Types of boilers include fire-tube, water-tube, electric, and biomass boilers

• Boilers work by heating water to produce steam, which is then used for various applications

• Safety norms include regular maintenance, proper ventilation, and adherence to safety codes and regulations

• Examples of safety features include pressure relief valves, w...read more

Different types of pumps are used for different applications. Pump selection criteria depend on factors like flow rate, head, viscosity, etc.

• Centrifugal pumps are used for low viscosity fluids and high flow rates

• Positive displacement pumps are used for high viscosity fluids and low flow rates

• Factors like flow rate, head, viscosity, temperature, pressure, etc. are considered while selecting a pump

• For example, a centrifugal pump may be selected for a cooling water application, ...read more

There are various types of conveyors, gears and gearboxes, and bearings used in mechanical maintenance. Pulling bearings requires proper technique.

• Types of conveyors include belt, roller, chain, and screw conveyors

• Types of gears include spur, helical, bevel, worm, and planetary gears

• Types of bearings include ball, roller, and sleeve bearings

• To pull a bearing, use a bearing puller tool and apply force evenly to avoid damage

There are various types of hydraulic valves, including pressure relief and pressure reducing valves.

• Types of hydraulic valves include directional control valves, flow control valves, pressure control valves, and check valves.

• Pressure relief valves are designed to limit the pressure within a hydraulic system by diverting excess fluid when the pressure reaches a certain level.

• Pressure reducing valves, on the other hand, are used to maintain a constant pressure in a branch of a ...read more

The temperature of cooling tower water can vary depending on the specific system and operating conditions.

• Cooling tower water temperature typically ranges from 70-85 degrees Fahrenheit.

• The temperature may be controlled by adjusting the flow rate of water through the tower or by adding chemicals to the water.

• Monitoring and maintaining the proper water temperature is important for the efficiency and effectiveness of the cooling system.

The company XYZ uses mobile cranes and blackhole loaders for mechanical maintenance. The capacity of the mobile crane varies depending on the model.

• The company XYZ utilizes mobile cranes and blackhole loaders for their mechanical maintenance operations.

• The capacity of the mobile crane can vary depending on the specific model being used.

• Unfortunately, the exact capacity of the mobile crane used by XYZ is not provided in the question.

In a clean room area, parameters observed include air quality, temperature, humidity, particle count, and pressure differentials.

• Air quality is monitored to ensure low levels of contaminants.

• Temperature is controlled to maintain a stable environment for sensitive equipment.

• Humidity levels are regulated to prevent moisture-related issues.

• Particle count is measured to ensure cleanliness and prevent contamination.

• Pressure differentials are maintained to prevent the entry of outs...read more

Blowers are used to push air through the tower, while air fins and cooling fans are used to dissipate heat from the tower.

• Blowers are responsible for creating airflow within the tower to cool the system.

• Air fins are heat exchangers that help dissipate heat from the tower by increasing surface area for heat transfer.

• Cooling fans are used to enhance the heat dissipation process by increasing airflow over the fins.

• Blowers are typically located at the base of the tower, while air...read more

The permissible vacuum drop for reactor vacuum testing depends on various factors such as the type of reactor and its design specifications.

• The permissible vacuum drop can vary depending on the type of reactor being tested.

• For some reactors, a vacuum drop of 5-10% may be considered acceptable.

• In other cases, a vacuum drop of less than 2% may be required.

• The specific permissible vacuum drop should be determined based on the reactor's design specifications and industry standard...read more

No, RT is not used in small bore socket weld.

• Small bore socket welds are typically inspected using visual inspection and dye penetrant testing.

• Radiographic testing (RT) is not necessary for small bore socket welds.

• RT is typically used for larger welds or critical applications where defects could have severe consequences.

To find out a worn bearing number, inspect the bearing for visible signs of wear and refer to the bearing manufacturer's documentation.

• Inspect the bearing for signs of wear such as discoloration, pitting, or scoring on the bearing surface.

• Check for excessive play or looseness in the bearing when it is rotated.

• Refer to the bearing manufacturer's documentation or catalog to identify the bearing number based on its physical characteristics.

• Measure the dimensions of the bearing a...read more

Maintenance is the process of keeping equipment in good condition. Preventive maintenance is scheduled maintenance to prevent breakdowns. Breakdown maintenance is repairing equipment after it has failed.

• Maintenance is the process of ensuring that equipment is in good working condition.

• Preventive maintenance is scheduled maintenance that is performed to prevent equipment breakdowns.

• Breakdown maintenance is the repair of equipment after it has failed.

• Preventive maintenance incl...read more

Maintenance engineer plays a crucial role in ensuring the smooth functioning of refinery operations.

• Developing and implementing maintenance strategies to minimize downtime and maximize efficiency

• Conducting regular inspections and identifying potential issues before they become major problems

• Coordinating with other departments to schedule maintenance activities and minimize disruption to production

• Ensuring compliance with safety regulations and maintaining a safe working envir...read more

Stacker and reclaiming path are used in material handling systems to store and retrieve bulk materials.

• Stacker is a large machine used to stack bulk materials in a specific pattern on a stockpile.

• Reclaiming path is used to retrieve the materials from the stockpile and transport them to the desired location.

• The path can be either a conveyor belt or a bucket wheel.

• The system is commonly used in industries such as mining, power plants, and cement plants.

Cooling towers are heat rejection devices used in HVAC systems to remove heat from the water-cooled system.

• Types of cooling towers include natural draft, mechanical draft, and hybrid.

• Cooling towers are used in power plants, chemical plants, and HVAC systems.

• Cooling performance calculation involves determining the heat load, water flow rate, and temperature difference.

• Factors affecting cooling tower performance include air temperature, humidity, and wind speed.

• Regular maintena...read more

I have worked with various types of machines including pumps, compressors, turbines, and conveyors.

• Pumps: Centrifugal pumps, reciprocating pumps

• Compressors: Reciprocating compressors, rotary screw compressors

• Turbines: Steam turbines, gas turbines

• Conveyors: Belt conveyors, screw conveyors

Prioritizing tasks based on importance and urgency is crucial for effective time management in mechanical maintenance engineering.

• Identify tasks that are both important and urgent, and prioritize them first.

• Consider the consequences of not completing a task on time - tasks with severe consequences should be prioritized.

• Delegate tasks that are important but not urgent to free up time for urgent tasks.

• Use tools like Eisenhower Matrix to categorize tasks based on importance and ...read more

Alignment of pump and motor involves ensuring proper positioning and parallelism to optimize performance and prevent damage.

• Start by checking the alignment specifications provided by the pump and motor manufacturers.

• Use alignment tools such as dial indicators, laser alignment systems, or reverse indicator method.

• Ensure the pump and motor shafts are clean and free from any debris or damage.

• Check and adjust the motor and pump base plates for proper leveling and alignment.

• Align ...read more

Debugging a program while it's being used requires using tools like logging, monitoring, and remote debugging.

• Use logging to track the flow of the program and identify any errors or issues.

• Implement monitoring tools to keep an eye on the program's performance and detect any anomalies in real-time.

• Utilize remote debugging techniques to troubleshoot and fix issues without interrupting the program's operation.

• Use breakpoints and watchpoints to pause the program at specific point...read more

To troubleshoot a crashing program, I would start by checking for error messages, reviewing recent changes, testing in a different environment, and debugging the code.

• Check for error messages to identify the cause of the crash

• Review recent changes in the program or system that may have caused the crash

• Test the program in a different environment to see if the crash is environment-specific

• Debug the code to identify and fix any issues causing the crash

Coal handling and loading/unloading equipment and systems

• Coal handling equipment includes conveyors, crushers, and feeders

• Loading and unloading equipment includes hoppers, chutes, and stackers/reclaimers

• Systems can be manual or automated, depending on the size and complexity of the operation

• Maintenance of equipment and systems is critical to ensure safe and efficient operation

Measuring instruments can be handled by following proper calibration procedures and ensuring their accuracy.

• Regularly calibrate measuring instruments to ensure accuracy

• Handle instruments with care to avoid damage

• Store instruments properly to prevent damage and maintain accuracy

• Follow manufacturer's instructions for use and maintenance

• Use appropriate measuring instruments for specific tasks

• Train personnel on proper handling and use of measuring instruments

Volvo Excavator 480 is a heavy-duty machine used for excavation work, with the numeric representing its model number and diesel consumption rate being an important factor for operational costs.

• The numeric '480' in Volvo Excavator 480 represents the model number of the machine.

• The diesel consumption rate of Volvo Excavator 480 can vary depending on factors such as load, operating conditions, and maintenance.

• Monitoring and optimizing diesel consumption can help reduce operation...read more

A thermal power plant generates electricity by converting heat energy into electrical energy through the use of steam turbines.

• Thermal power plants burn fossil fuels such as coal, natural gas, or oil to heat water and produce steam.

• The steam is then used to drive a turbine connected to a generator, which produces electricity.

• The waste heat from the turbine is usually released into the environment through cooling towers or other methods.

• Thermal power plants require large amoun...read more

Types of welding include arc welding, gas welding, and resistance welding.

• Arc welding uses an electric arc to create heat and join metals, commonly used in construction and fabrication.

• Gas welding involves the use of a fuel gas and oxygen to create a flame for melting and joining metals, commonly used in automotive repairs.

• Resistance welding uses the application of pressure and electric current to join metals, commonly used in the automotive and aerospace industries.

• Each type...read more

2 stroke engines have a power stroke in each revolution, while 4 stroke engines have a power stroke in every other revolution.

• 2 stroke engines have a simpler design and are lighter than 4 stroke engines.

• 2 stroke engines have a higher power-to-weight ratio compared to 4 stroke engines.

• 4 stroke engines are more fuel-efficient and produce less pollution than 2 stroke engines.

• Examples of 2 stroke engines include chainsaws, motorcycles, and outboard motors, while examples of 4 str...read more

De-ashing process from ESP to silo involves several steps.

• The ash is collected in hoppers located at the bottom of the ESP.

• The ash is then transported to the silo using a pneumatic conveying system.

• The ash is stored in the silo until it can be disposed of properly.

• Regular maintenance of the ESP and pneumatic conveying system is necessary to ensure efficient de-ashing.

• Proper safety measures must be taken during the de-ashing process to prevent accidents.

A boiler is a closed vessel used to generate steam. A cooling tower is a heat rejection device. A pump is a device used to move fluids.

• Boiler is used to generate steam by heating water.

• Cooling tower is used to reject heat from a process.

• Pump is used to move fluids from one place to another.

• Types of pump include centrifugal, positive displacement, and axial flow pumps.

There are three types of mechanical maintenance: preventive, corrective, and predictive.

• Preventive maintenance involves regular inspections and maintenance to prevent breakdowns.

• Corrective maintenance is performed after a breakdown has occurred to restore equipment to working condition.

• Predictive maintenance uses data analysis to predict when maintenance will be needed and prevent breakdowns.

• Examples of mechanical maintenance include lubrication, cleaning, replacing worn part...read more

Implement preventive maintenance and security measures to stop HSD theft from site.

• Regularly inspect fuel tanks and pipelines for any signs of tampering or leakage.

• Install security cameras and alarms to monitor the site and deter theft.

• Implement strict access control measures to limit entry to authorized personnel only.

• Conduct background checks on employees and contractors to prevent insider theft.

• Train employees on the importance of security and reporting any suspicious acti...read more

In cold rolling mill process, the structure of steel is altered through compression and deformation.

• Cold rolling reduces the thickness of steel by compressing it between rollers

• This process increases the strength and hardness of the steel

• Grain structure of the steel becomes elongated and aligned in the direction of rolling

• Cold rolling can also improve the surface finish and dimensional accuracy of the steel

• Examples: Cold rolled steel sheets used in automotive industry for bod...read more

The tube mill shaft should undergo heat treatment to improve its strength and durability.

• The most common heat treatment for tube mill shafts is quenching and tempering.

• Quenching involves heating the shaft to a high temperature and then rapidly cooling it in water or oil to increase its hardness.

• Tempering is done after quenching to reduce the brittleness caused by the rapid cooling process.

• Other heat treatment methods like annealing or normalizing may also be used depending on...read more

Thermal power plant generates electricity by converting heat energy into electrical energy.

• Fuel is burned to produce heat

• Heat is used to convert water into steam

• Steam drives the turbine which generates electricity

• Cooling system is used to condense the steam back into water

• Electricity is then transmitted to the grid for distribution

Carnot cycle is a theoretical thermodynamic cycle that operates between two heat reservoirs to achieve maximum efficiency.

• Carnot cycle consists of four reversible processes: isothermal expansion, adiabatic expansion, isothermal compression, and adiabatic compression.

• The efficiency of Carnot cycle is given by the formula: Efficiency = 1 - (Tc/Th), where Tc is the temperature of the cold reservoir and Th is the temperature of the hot reservoir.

• Carnot cycle is an idealized cycle...read more