20+ Junior Engineer Mechanical Maintenance Interview Questions and Answers

Ozone (O₃) is found higher in the atmosphere due to its formation process and stability, despite being heavier than oxygen (O₂).

• Ozone is formed from oxygen molecules (O₂) when exposed to ultraviolet (UV) light, primarily in the stratosphere.

• Ozone's formation occurs at high altitudes where UV radiation is more intense, leading to its concentration in the ozone layer.

• O₂ is more stable and abundant at lower altitudes where it is produced by photosynthesis and is essential for li...read more

Steam is discharged from the body during winter bathing due to the difference in temperature between the body and the surrounding air.

• The body is warmer than the surrounding air, causing the moisture on the skin to evaporate and form steam.

• The steam is visible due to the cold air condensing the water vapor.

• This is a natural process and does not indicate any medical condition.

Control valve internal leakages can be checked through various methods.

• Performing a visual inspection of the valve and its components

• Using ultrasonic leak detection equipment

• Conducting a pressure drop test

• Performing a bubble test using a soap solution

• Checking the valve position indicator

• Analyzing the valve's performance data

• Regular maintenance and testing of the valve

A pump is a mechanical device used to move fluids from one place to another. There are different types of pumps based on their working principle and application.

• Types of pumps include centrifugal pumps, positive displacement pumps, reciprocating pumps, and rotary pumps.

• Centrifugal pumps use a rotating impeller to create a flow of fluid.

• Positive displacement pumps trap a fixed amount of fluid and then force it into a discharge pipe.

• Reciprocating pumps use a piston or diaphragm...read more

Troubleshooting machine starting issues involves checking power supply, controls, and mechanical components systematically.

• Check the power supply: Ensure the machine is receiving the correct voltage and current.

• Inspect control systems: Verify that all switches, relays, and sensors are functioning properly.

• Examine mechanical components: Look for any jams or obstructions in moving parts.

• Review safety interlocks: Ensure that all safety mechanisms are disengaged to allow operatio...read more

Series and parallel connections are two types of electrical circuits used to connect components.

• In a series connection, components are connected end-to-end, so the current flows through each component in turn.

• In a parallel connection, components are connected side-by-side, so the current is divided among them.

• Series connections increase the total resistance and decrease the total current, while parallel connections decrease the total resistance and increase the total current....read more

Zero breakdown in line maintenance is the goal of any maintenance team.

• Regular preventive maintenance checks

• Proper lubrication of machines

• Timely replacement of worn-out parts

• Training of maintenance staff

• Use of advanced technologies like predictive maintenance

• Continuous monitoring of equipment performance

HEPA stands for High-Efficiency Particulate Air, a filter that captures 99.97% of particles as small as 0.3 microns.

• HEPA filters are commonly used in air purifiers to improve indoor air quality.

• They are essential in hospitals to prevent airborne infections.

• Used in vacuum cleaners to trap dust and allergens.

• Found in HVAC systems to enhance air filtration efficiency.

Breaking failure can be solved by identifying the root cause and implementing corrective actions.

• Identify the root cause of the breaking failure

• Implement corrective actions such as repairing or replacing the broken parts

• Conduct regular maintenance and inspections to prevent future breaking failures

• Train employees on proper usage and maintenance of equipment

• Use high-quality materials and equipment to reduce the risk of breaking failures

Instrument and material differences are related to the type and function of equipment used in mechanical maintenance.

• Instruments are tools used to measure, monitor, or control various parameters such as temperature, pressure, flow rate, etc.

• Materials are substances used to construct or repair equipment, such as metals, plastics, ceramics, etc.

• Instruments are typically electronic or mechanical devices, while materials can be natural or synthetic.

• Examples of instruments include...read more

Pump is used to transfer fluids while motor is used to convert electrical energy into mechanical energy.

• Pump is used to move fluids from one place to another while motor is used to rotate machinery.

• Pump has an inlet and outlet while motor has a rotor and stator.

• Pump is used in fluid systems while motor is used in mechanical systems.

• Examples of pumps include centrifugal pumps, positive displacement pumps, and axial flow pumps. Examples of motors include AC motors, DC motors, a...read more

Bearings are mechanical components that reduce friction between moving parts, enhancing efficiency and longevity.

• 1. Ball Bearings: Commonly used in electric motors and bicycles for smooth rotation.

• 2. Roller Bearings: Used in heavy machinery and automotive applications for load support.

• 3. Needle Bearings: Ideal for applications with limited space, such as in gearboxes.

• 4. Thrust Bearings: Designed to handle axial loads, often found in automotive applications.

• 5. Magnetic Bearing...read more

Possible causes of slow hydraulic cylinder operation

• Low hydraulic fluid level

• Clogged or dirty hydraulic filter

• Worn out piston seals

• Leaking hydraulic lines

• Faulty control valve

• Incorrectly adjusted relief valve

• Excessive load on the cylinder

• Improperly sized cylinder for the application

Varniyour list count refers to a method for tracking and managing maintenance tasks in engineering.

• Varniyour list count helps prioritize maintenance activities based on urgency and importance.

• It can be used to track the number of tasks completed versus pending.

• For example, in a mechanical maintenance context, it may include tasks like equipment inspections, repairs, and replacements.

• This method aids in resource allocation and scheduling for maintenance teams.

A hydraulic system is a technology that uses liquid to transmit power.

• Uses incompressible fluid to generate power

• Consists of a pump, valves, cylinders, and hydraulic fluid

• Commonly used in heavy machinery like excavators and cranes

The fuel system is responsible for delivering fuel to the engine for combustion.

• The fuel system includes the fuel tank, fuel pump, fuel filter, fuel injectors, and carburetor.

• The fuel pump draws fuel from the tank and sends it to the engine.

• The fuel filter removes impurities from the fuel before it reaches the engine.

• Fuel injectors spray fuel into the engine's combustion chamber, while a carburetor mixes fuel and air before sending it to the engine.

• The fuel system must be reg...read more

Air pressure is the force exerted by air molecules in a given area, measured in units like Pascals or psi.

• Standard atmospheric pressure at sea level is approximately 101.3 kPa (kilopascals) or 14.7 psi (pounds per square inch).

• Air pressure decreases with altitude; for example, at 5,000 feet, it is about 84 kPa.

• Air pressure is crucial in various applications, such as tire inflation, where proper pressure ensures safety and efficiency.

• In weather systems, low air pressure often ...read more

Cooling towers are heat rejection devices that expel waste heat to the atmosphere through the cooling of water.

• Natural Draft Cooling Towers: Use natural convection to circulate air; examples include hyperbolic cooling towers.

• Mechanical Draft Cooling Towers: Use fans to force air through the tower; examples include induced draft and forced draft towers.

• Wet Cooling Towers: Utilize water evaporation to cool; commonly used in power plants.

• Dry Cooling Towers: Use air to cool witho...read more

Bearings are mechanical components that reduce friction between moving parts, enhancing efficiency and lifespan.

• 1. Ball Bearings: Use spherical balls to maintain separation between the bearing races. Example: skateboard wheels.

• 2. Roller Bearings: Utilize cylindrical rollers for load distribution. Example: heavy machinery.

• 3. Needle Bearings: A type of roller bearing with long, thin rollers. Example: automotive applications.

• 4. Thrust Bearings: Designed to handle axial loads. Ex...read more