400+ Diploma Trainee Engineer Interview Questions and Answers

Kirchhoff's Current Law states that the algebraic sum of currents meeting at a point in an electrical network is zero.

• Kirchhoff's Current Law is also known as the junction rule.

• It is based on the principle of conservation of charge.

• The law applies to both DC and AC circuits.

• It is used to analyze and solve complex electrical circuits.

• An example of applying Kirchhoff's Current Law is when determining the current flowing through different branches of a parallel circuit.

Possible reasons for heavy white smoke

• Burning of coolant in the engine

• Leaking head gasket

• Faulty fuel injectors

• Burning of transmission fluid

• Excessive condensation in the exhaust system

Electrical CAD is used to design and document electrical systems. Perpendicularity symbol is drawn using CAD tools.

• Electrical CAD helps in creating accurate and detailed electrical designs

• It allows for easy modification and updating of designs

• CAD tools can be used to draw symbols for various electrical components and properties

• To draw the symbol of perpendicularity, use the CAD tool for drawing lines and add a small square at the intersection of the lines

• The perpendicularity ...read more

Tata Cummins engines are of two types - B and C series.

• Tata Cummins engines are manufactured by Tata Motors and Cummins Inc.

• B series engines are 3.9L to 5.9L in displacement and are used in light and medium-duty vehicles.

• C series engines are 8.3L to 15L in displacement and are used in heavy-duty vehicles.

• Tata Cummins engines are known for their fuel efficiency and reliability.

Before replacing a fuse, one should take certain precautions to ensure safety.

• Ensure that the power supply is turned off before replacing the fuse.

• Identify the correct type and rating of the fuse to be replaced.

• Use appropriate safety equipment such as insulated gloves and goggles.

• Inspect the fuse holder for any signs of damage or overheating.

• Check for any underlying issues that may have caused the fuse to blow.

• Follow the manufacturer's instructions and guidelines for fuse rep...read more

Moulding is a manufacturing process of shaping liquid or pliable raw material using a rigid frame called a mold.

• Types of moulding: injection moulding, blow moulding, compression moulding, rotational moulding, etc.

• Forging is a manufacturing process of shaping metal using compressive forces.

• LPDC stands for Low Pressure Die Casting, a casting process for producing metal parts.

• Materials used for moulding: plastic, rubber, metal, glass, etc.

AC can be converted to DC using a rectifier circuit. The circuit diagram includes a transformer, diodes, and a filter capacitor.

• AC to DC conversion is achieved using a rectifier circuit.

• A rectifier circuit consists of a transformer, diodes, and a filter capacitor.

• The transformer steps down the AC voltage to a lower level.

• Diodes are used to convert the AC voltage to pulsating DC.

• The filter capacitor smoothens the pulsating DC to obtain a steady DC output.

• The circuit diagram ca...read more

The types of materials used in engines vary depending on the specific engine type and its components.

• Engines can be made of various materials such as cast iron, aluminum, steel, and alloys.

• Different engine parts may require different materials, for example, pistons are often made of aluminum alloy.

• Engine components like cylinder heads, crankshafts, and connecting rods can be made of cast iron or steel.

• Some engines may also use specialized materials like carbon fiber for light...read more

The least count is the smallest measurement that can be made using a measuring instrument.

• Least count is the resolution or precision of a measuring instrument.

• It determines the smallest unit of measurement that can be read on the instrument.

• For a vernier caliper, the least count is the difference between one main scale division and one vernier scale division.

• The formula to calculate the least count of a vernier caliper is: Least Count = (1 main scale division) - (1 vernier sc...read more

Rectifier, types of motor, difference between servo motor and induction motor

• Rectifier is an electrical device that converts alternating current (AC) to direct current (DC)

• Types of motors include DC motors, AC motors, servo motors, and induction motors

• Servo motors are used in applications that require precise control of position, velocity, and acceleration

• Induction motors are commonly used in industrial applications due to their robustness and simplicity

• Difference between ser...read more

Major specifications to consider when buying an AC include cooling capacity, energy efficiency, noise level, and brand reputation.

• Cooling capacity measured in BTUs or tons

• Energy efficiency rating like EER or SEER

• Noise level in decibels

• Brand reputation for reliability and customer service

Diesel engines use compression ignition while petrol engines use spark ignition.

• Diesel engines use compression ignition while petrol engines use spark ignition

• Diesel engines are more fuel efficient than petrol engines

• Petrol engines generally have higher power output compared to diesel engines

• Diesel engines have higher torque at lower RPMs

• Diesel engines are typically more durable and have longer lifespans than petrol engines

There are various operations that can be performed on a lathe machine, including turning, facing, drilling, boring, knurling, and threading.

• Turning - used to create cylindrical parts

• Facing - used to create a flat surface at the end of a workpiece

• Drilling - used to create holes in the workpiece

• Boring - used to enlarge existing holes

• Knurling - used to create a textured pattern on the surface of the workpiece

• Threading - used to create threads on the workpiece

A transformer is an electrical device that transfers electrical energy from one circuit to another through electromagnetic induction.

• Transformers are used to either step up or step down voltage levels.

• Step down transformers decrease voltage levels, while step up transformers increase voltage levels.

• Types of transformers include power transformers, distribution transformers, isolation transformers, autotransformers, and instrument transformers.

• Power transformers are used in po...read more

Backward stroke is the return stroke of the ram in shaping machine, while forward stroke is the cutting stroke.

• Backward stroke is when the ram moves away from the workpiece

• Forward stroke is when the ram moves towards the workpiece to make the cut

• Backward stroke is non-cutting, while forward stroke is cutting

• Backward stroke allows the tool to clear the workpiece, while forward stroke performs the cutting operation

Mechanical engineering deals with designing and manufacturing mechanical systems, while Automobile engineering focuses on designing and manufacturing vehicles.

• Mechanical engineering involves designing and manufacturing various mechanical systems such as engines, HVAC systems, and manufacturing equipment.

• Automobile engineering specifically focuses on designing and manufacturing vehicles like cars, motorcycles, and trucks.

• Mechanical engineers work on a wide range of projects be...read more

List of technical questions for Diploma Engineer Trainee

• What is the difference between AC and DC current?

• Explain the working of a transformer.

• What is the purpose of a capacitor?

• What is the difference between a diode and a transistor?

• Explain the working of a 4-stroke engine.

• What is the function of a clutch in a manual transmission?

• What is the difference between a hub and a switch in networking?

• Explain the OSI model.

• What is the difference between a compiler and an interpreter?

• W...read more

Four stroke engines have separate intake, compression, power, and exhaust strokes, while two stroke engines combine these strokes.

• Four stroke engines have a longer cycle and require more parts than two stroke engines.

• Four stroke engines are more fuel efficient and produce less pollution than two stroke engines.

• Two stroke engines are simpler in design and have a higher power-to-weight ratio than four stroke engines.

• Two stroke engines are commonly used in small power tools and ...read more

A resistor is an electronic component that limits the flow of electric current in a circuit.

• Resistors are used to control the amount of current flowing through a circuit.

• They are passive components that dissipate energy in the form of heat.

• Resistors are measured in ohms (Ω) and have color-coded bands to indicate their resistance value.

• They can be fixed resistors with a specific resistance value or variable resistors that can be adjusted.

• Resistors are commonly used in voltage ...read more

CNC stands for Computer Numerical Control and VMC stands for Vertical Machining Center. Mechanical engineering involves designing, analyzing, and manufacturing mechanical systems. Manufacturing is the process of converting raw materials into finished products, while production refers to the overall process of creating goods.

• CNC is a manufacturing process that uses computerized controls to operate machine tools.

• VMC is a type of CNC machine that operates in a vertical orientati...read more

Commercial and domestic voltage varies depending on the country and region.

• Commercial voltage is typically higher than domestic voltage.

• In the United States, commercial voltage is usually 120/208 volts or 277/480 volts.

• In residential areas of the United States, domestic voltage is typically 120/240 volts.

• In Europe, commercial voltage is often 230/400 volts, while domestic voltage is 230 volts.

• Frequency of supply voltage is usually 50 or 60 Hz, depending on the country.

Providing better quality and low cost products is our duty towards customers.

• We can achieve this by optimizing our production process and reducing wastage.

• We can also negotiate better deals with suppliers to reduce raw material costs.

• Using technology to automate certain processes can also help reduce costs.

• We should also focus on continuous improvement to ensure that our products are of the highest quality.

• Offering discounts or promotions can also help attract customers while...read more

Production is the process of creating goods or services, while manufacturing is the process of making products on a large scale.

• Production involves creating goods or services from raw materials or components.

• Manufacturing involves the use of machines, tools, and labor to produce goods on a large scale.

• Production can be done on a small scale, while manufacturing is typically done on a large scale.

• Examples of production include baking a cake or providing a service like haircuts...read more

Air conditioning and refrigeration systems work on the principle of heat transfer and phase change of refrigerant.

• Air conditioning system cools and dehumidifies air in a room or building.

• Refrigeration system removes heat from a space and transfers it to the outside environment.

• Both systems use a refrigerant to absorb and release heat through phase change.

• Air conditioning system uses a compressor, evaporator, condenser, and expansion valve to circulate refrigerant.

• Refrigeratio...read more

High pressure die casting is a metal casting process in which molten metal is injected into a steel mold under high pressure.

• Molten metal is injected into a steel mold under high pressure

• The mold is designed to create complex shapes with high accuracy

• The process is used to produce parts with high strength and dimensional accuracy

• Commonly used metals include aluminum, zinc, and magnesium

• Used in automotive, aerospace, and consumer electronics industries

Steam in a boiler is generated by heating water to its boiling point. There are various types of boilers, such as fire tube, water tube, and electric boilers.

• Boilers generate steam by heating water to its boiling point

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

• Fire tube boilers have hot gases flowing through tubes that are surrounded by water

• Water tube boilers have water flowing through tubes that are heated by combustion gases

• Electric boilers use ele...read more

The functions of parts of an Air Conditioner include cooling, dehumidifying, filtering, and circulating air.

• Compressor: compresses and circulates refrigerant to cool the air

• Condenser: releases heat from the refrigerant to the outside air

• Evaporator: absorbs heat from the air and cools it down

• Expansion valve: regulates the flow of refrigerant into the evaporator

• Fan: circulates the air over the evaporator and condenser coils

• Filter: removes dust, pollen, and other particles from ...read more

PNP and NPN transistors are two types of bipolar junction transistors with opposite polarity.

• PNP has a layer of N-type semiconductor sandwiched between two layers of P-type semiconductor, while NPN has a layer of P-type semiconductor sandwiched between two layers of N-type semiconductor.

• In PNP, the current flows from the emitter to the base and then to the collector, while in NPN, the current flows from the emitter to the collector through the base.

• PNP is used in high-side sw...read more

Two stroke engines have a power stroke every two strokes of the piston, while four stroke engines have a power stroke every four strokes.

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

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

• Examples of two stroke engines include chainsaws and dirt bikes, while examples of four stroke engines i...read more

A flywheel is a mechanical device used to store rotational energy and smooth out fluctuations in speed of a rotating shaft.

• Flywheels store energy by increasing their rotational speed.

• They release energy by slowing down their rotational speed.

• Flywheels are commonly used in engines to maintain a constant speed and reduce vibrations.

• They are also used in vehicles to provide momentum during gear changes.

Computer Numerical Control

• Stands for Computer Numerical Control

• Used in manufacturing processes to control machining tools and equipment

• Automates the operation of machines based on pre-programmed sequences of commands

• Examples include CNC milling machines, CNC routers, CNC lathes

The iron carbon diagram is a graphical representation of the phases and microstructures that form as a result of the cooling and heating of iron-carbon alloys.

• It shows the relationship between the carbon content and the phases present in iron-carbon alloys.

• It helps in understanding the behavior of steels and cast irons during heat treatment.

• The diagram consists of three main regions: austenite, ferrite, and cementite.

• The phases present in the diagram include ferrite, pearlite...read more

Types of fit include clearance fit, interference fit, transition fit, etc.

• Clearance fit: parts are intended to have a gap between them, such as a shaft and a hole

• Interference fit: parts are intended to be pressed or forced together, such as a bearing and a shaft

• Transition fit: parts have both clearance and interference, such as a piston and a cylinder

• Other types of fit include force fit, shrink fit, and sliding fit

There are various types of valves used in hydraulic systems.

• There are directional control valves, pressure control valves, flow control valves, and check valves.

• Directional control valves control the direction of fluid flow.

• Pressure control valves regulate the pressure of the fluid.

• Flow control valves regulate the flow rate of the fluid.

• Check valves allow fluid to flow in one direction only.

• Other types of valves include relief valves, sequence valves, and throttle valves.

The micrometre least count formula is the ratio of the pitch of the screw gauge to the number of divisions on the circular scale.

• The formula is LC = Pitch / Number of divisions on circular scale

• LC stands for least count

• Pitch is the distance moved by the spindle per revolution

• The number of divisions on the circular scale is the number of equally spaced divisions on the circular scale

• The formula is used to calculate the smallest measurement that can be made with a screw gauge

• Fo...read more

Vernier caliper diagram is used to understand the parts and functioning of the instrument.

• The diagram helps in identifying the main scale, vernier scale, jaws, depth gauge, and locking screw.

• It also shows how to read the measurements accurately using the vernier scale.

• The diagram is useful for beginners who are learning to use the vernier caliper.

• It is also helpful for troubleshooting and maintenance purposes.

• For example, if the jaws are not closing properly, the diagram can ...read more

The best manufacturing process depends on the product being manufactured and its requirements.

• Each manufacturing process has its own advantages and disadvantages.

• For example, injection molding is best for mass production of small and complex parts, while CNC machining is better for low-volume production of larger parts.

• The choice of manufacturing process also depends on factors such as cost, time, and quality requirements.

• Therefore, it is important to analyze the product and ...read more

Vehicles rely on electrical systems for various functions such as starting the engine, powering lights and entertainment systems, and charging the battery.

• Electrical systems are responsible for starting the engine and powering various components such as lights, wipers, and entertainment systems.

• The battery is charged by the alternator, which is driven by the engine.

• Modern vehicles also have complex computer systems that rely on electrical signals to operate.

• Electric and hybri...read more

I chose mechanical engineering because of my interest in machines and mechanisms. I have knowledge of engines, boilers, and computer skills.

• I have always been fascinated by how machines work and how they can be improved.

• Mechanical engineering offers a wide range of career opportunities in various industries.

• I have studied the principles of mechanics, thermodynamics, and materials science.

• An engine is a machine that converts fuel into mechanical energy to power vehicles or mac...read more

The second law of thermodynamics states that the total entropy of a closed system always increases over time.

• Entropy of a system tends to increase over time

• Heat cannot spontaneously flow from a colder location to a hotter location

• Efficiency of a heat engine is always less than 100%

• Entropy of the universe is always increasing

First law of thermodynamics states that energy cannot be created or destroyed, only transferred or converted. Second law states that entropy of an isolated system always increases over time.

• First law is also known as law of conservation of energy

• Second law explains why heat flows from hot to cold objects

• Second law also states that no engine can be 100% efficient

• Entropy is a measure of disorder in a system

• Both laws are fundamental to understanding energy and its transformation...read more

Operational Amplifier (Op-Amp) is a popular Linear Integrated Circuit.

• Op-Amp is used in various applications such as amplifiers, filters, oscillators, comparators, etc.

• Some popular Op-Amps are LM741, LM358, LM324, etc.

• Op-Amps have high input impedance, low output impedance, and high gain.

• Op-Amps can be used in both inverting and non-inverting configurations.

Generators and motors work on the principle of electromagnetic induction.

• Generators convert mechanical energy into electrical energy through electromagnetic induction

• Motors convert electrical energy into mechanical energy through electromagnetic induction

• Both devices rely on the interaction between magnetic fields and conductors to function effectively

Process heat transfer operations involve the transfer of heat from one medium to another in a chemical or physical process.

• Heat exchangers

• Condensers

• Reboilers

• Evaporators

• Cooling towers

• Furnaces

• Boilers

• Distillation columns

• Crystallizers

Valves used in industry include gate, globe, ball, butterfly, diaphragm, and check valves.

• Gate valves are used for on/off control of flow

• Globe valves are used for regulating flow

• Ball valves are used for quick shut-off

• Butterfly valves are used for low-pressure applications

• Diaphragm valves are used for corrosive or abrasive fluids

• Check valves are used to prevent backflow

Governor regulates the speed of an engine. Moulding machine and punching are manufacturing processes. Flywheel stores energy. Vernier caliper measures length.

• Governor is a device that controls the speed of an engine by regulating the fuel or steam supply.

• Moulding machine is used to shape molten metal or plastic into a desired form.

• Punching is a process of creating holes or shapes in a material using a punch and die.

• Flywheel is a mechanical device that stores energy by resisti...read more

Estimation of column, IS codes, Drawing Reading etc.

• Estimation of column involves calculating the required amount of materials and labor for construction.

• IS codes refer to the Indian Standards codes that provide guidelines for construction and engineering practices.

• Drawing reading involves interpreting technical drawings and blueprints to understand the design and specifications of a structure.

• Knowledge of these concepts is essential for a Diploma Trainee Engineer to effectiv...read more