1000+ Electrical Engineer Interview Questions and Answers

Efficiency of a transformer is maximum when the copper losses are equal to iron losses.

• Efficiency is maximum when the transformer is operating at its full load capacity.

• Copper losses are caused by the resistance of the wire used in the transformer's windings.

• Iron losses are caused by the magnetic properties of the transformer's core.

• Efficiency can be improved by using high-quality materials and reducing the air gap between the core and windings.

• Efficiency can also be improved...read more

Reverse arc flashing on ACB breaker refers to the phenomenon where the arc flash occurs on the opposite side of the contacts during the opening operation.

• Reverse arc flashing happens when the arc flash occurs on the side of the contacts opposite to the normal direction during the opening operation of the ACB breaker.

• This phenomenon can be caused by factors such as high fault currents, improper maintenance, or inadequate arc flash protection.

• Reverse arc flashing can pose a saf...read more

The current carrying capacity of a 185sqmm al cable depends on various factors such as the material, insulation, and installation method.

• The current carrying capacity of a cable is typically determined by the manufacturer and specified in the cable's datasheet.

• Factors such as the material (aluminum in this case), insulation type, ambient temperature, and installation method all affect the current carrying capacity.

• For a 185sqmm aluminum cable, the current carrying capacity ca...read more

CB is a switch that can interrupt the circuit during fault conditions, while an isolator is a switch that can only isolate the circuit.

• CB is used for protection against overcurrent, short circuit, and earth fault

• Isolator is used for isolation of a circuit for maintenance or repair work

• CB can be operated manually or automatically, while isolator is operated manually only

• CB has contacts that can break the circuit, while isolator has no such contacts

An AC drive circuit diagram controls the speed of an AC motor by varying the frequency and voltage of the power supplied to it.

• An AC drive consists of a rectifier, DC link, inverter, and control circuitry.

• The rectifier converts AC power to DC power, which is stored in the DC link.

• The inverter converts the DC power back to AC power with variable frequency and voltage.

• The control circuitry adjusts the frequency and voltage of the output to control the motor speed.

• Examples of AC...read more

One horsepower is equal to approximately 746 watts.

• One horsepower is a unit of power commonly used to measure the output of engines and motors.

• It is equivalent to approximately 746 watts.

• The conversion factor between horsepower and watts is 746.

• For example, a 1 horsepower motor would consume or produce approximately 746 watts of power.

Types of GI top channels, cross angles, types of DTR, rating of DTR, current capacity of DTRs.

• Types of GI top channels include GI plain channels and GI perforated channels.

• Cross angles are used to provide additional support and stability to structures.

• Types of DTR (Distribution Transformer Rectifier) include single-phase and three-phase.

• Rating of DTR is typically in kVA (kilo Volt-Ampere) and can range from 25 kVA to 2000 kVA.

• Current capacity of DTRs varies based on the ratin...read more

SAT (Site Acceptance Test) is done for cables to ensure their healthiness.

• SAT is a series of tests performed on cables to verify their performance and functionality.

• It includes tests like insulation resistance, continuity, voltage withstand, and cable length measurement.

• SAT helps in identifying any faults or defects in the cables and ensures their proper functioning.

• For example, in power transmission systems, SAT is conducted to ensure the cables can handle the required volta...read more

An induction motor is an AC electric motor in which power is supplied to the rotor by electromagnetic induction.

• Induction motors are widely used in various applications, including industrial machinery, household appliances, and transportation systems.

• They work based on the principle of electromagnetic induction, where a rotating magnetic field is created by the stator winding, inducing current in the rotor.

• The rotor of an induction motor can be either squirrel cage or wound t...read more

The starting current of an induction motor is typically 5 to 7 times the rated current.

• The starting current of an induction motor is higher than its rated current.

• The exact starting current depends on the motor design and load conditions.

• Starting current can be 5 to 7 times the rated current for most induction motors.

• High starting currents can cause voltage drops and affect the stability of the electrical system.

• Motor starters and soft starters are used to limit the starting ...read more

DMZ is a network segment that separates an internal network from an external network.

• DMZ stands for Demilitarized Zone.

• It acts as a buffer zone between the internet and the internal network.

• It contains servers that are accessible from the internet, but not the internal network.

• It enhances security by limiting direct access to the internal network.

• Examples of servers in DMZ include web servers, email servers, and FTP servers.

Motors require a load to convert electrical energy into mechanical energy.

• A motor works by converting electrical energy into mechanical energy

• The load is the object that the motor is designed to move or operate

• Without a load, the motor may spin uncontrollably or not at all

• Examples of loads include fans, pumps, conveyor belts, and elevators

The two types of winding in electrical engineering are lap winding and wave winding.

• Lap winding is used in DC machines and is characterized by multiple parallel paths for current flow.

• Wave winding is used in AC machines and is characterized by a single path for current flow.

• Lap winding provides high current capacity and low voltage output, while wave winding provides low current capacity and high voltage output.

• In lap winding, the number of parallel paths is equal to the numb...read more

The current unit is the ampere (A), which measures the flow of electric charge.

• The unit of electric current is the ampere (A).

• Current is the rate of flow of electric charge.

• It is measured using an ammeter.

• One ampere is equal to one coulomb of charge passing through a point in one second.

A sensor is a device that detects and responds to some type of input from the physical environment.

• Sensors can be classified into various types such as temperature sensors, pressure sensors, proximity sensors, etc.

• They can be analog or digital, active or passive, and can use different sensing principles such as resistive, capacitive, inductive, etc.

• Sensors are widely used in various applications such as automotive, aerospace, medical, industrial, etc.

• Examples of sensors inclu...read more

My current payment is $80,000 annually before taxes and $65,000 after taxes.

• My current annual salary is $80,000 before taxes

• After taxes, my take-home pay is $65,000

• I receive a monthly salary of $6,666.67 before taxes

DG is a backup power source for a plant. It works by converting fuel into electricity.

• DG stands for Diesel Generator

• It is required for a plant to ensure uninterrupted power supply in case of power outages or grid failures

• DG works by converting fuel (usually diesel) into mechanical energy which is then converted into electrical energy

• It consists of an engine, alternator, fuel system, cooling system, and control panel

• DGs are available in various sizes and capacities depending o...read more

The P.I test in transformers is performed to determine the insulation condition and losses in the transformer.

• P.I test stands for Polarization Index test.

• It is a type of insulation resistance test.

• The test measures the ratio of insulation resistance at 10 minutes to the insulation resistance at 1 minute.

• The test helps in assessing the insulation condition and detecting any moisture or contamination in the transformer.

• A high P.I value indicates good insulation, while a low val...read more

Various methods like V/F control, rotor resistance control, and vector control are used for speed control of induction motors.

• V/F control method varies the frequency and voltage supplied to the motor to control its speed.

• Rotor resistance control method involves inserting external resistance in the rotor circuit to control the speed.

• Vector control method uses advanced algorithms to control the speed and torque of the motor.

• Pulse width modulation (PWM) technique is used in some...read more

DTR structure consists of transformer, rectifier, and filter components.

• Transformer: used to step down the voltage from the power source

• Rectifier: used to convert AC to DC

• Filter: used to smooth out the DC output

• Components may include diodes, capacitors, resistors, and inductors

• Example: DTR structure is commonly used in power supplies for electronic devices

VFD stands for Variable Frequency Drive. It is an electronic device that controls the speed of an AC motor.

• VFD is used to save energy by controlling the speed of the motor according to the load.

• It can also improve the lifespan of the motor by reducing wear and tear.

• VFD can be used in various applications such as pumps, fans, conveyors, and compressors.

• It works by converting the incoming AC power to DC and then back to AC at a variable frequency.

• VFD can provide precise control...read more

FLP cables are used in hazardous environments where there is a risk of explosion due to flammable gases or vapors.

• Used in oil refineries

• Chemical plants

• Pharmaceutical manufacturing facilities

• Gas processing plants

SMPS are power supplies that use high-frequency switching to convert electrical power efficiently.

• SMPS are more efficient than linear power supplies.

• They use high-frequency switching to regulate the output voltage.

• Common types include buck, boost, and buck-boost converters.

• SMPS are widely used in electronics due to their compact size and high efficiency.

• Examples of SMPS applications include computers, LED lighting, and industrial equipment.

Safety instructions in previous plant included wearing appropriate PPE, following lockout/tagout procedures, and attending regular safety training.

• Wearing appropriate PPE (Personal Protective Equipment) such as safety glasses, gloves, and hard hats

• Following lockout/tagout procedures when working on electrical equipment to prevent accidental startup

• Attending regular safety training sessions to stay updated on safety protocols and procedures

C is a low-level programming language while Java is a high-level object-oriented language.

• C is a procedural language while Java is an object-oriented language.

• C has manual memory management while Java has automatic garbage collection.

• C is platform-dependent while Java is platform-independent.

• C supports pointers while Java does not.

• C is typically used for system-level programming while Java is used for application development.

Yes, I have experience working with gas turbines in my previous role as an Electrical Engineer.

• I have worked on the maintenance and troubleshooting of gas turbines in power plants.

• I have experience with the electrical systems and controls related to gas turbines.

• I have collaborated with mechanical engineers to optimize the performance of gas turbines.

• I have conducted tests and inspections on gas turbines to ensure efficiency and safety.

The installation procedure of a new transformer involves testing the BDV of oil and filtering the oil.

• Inspect the site and ensure it meets safety requirements

• Transport the transformer to the site and position it correctly

• Connect the transformer to the electrical system

• Test the BDV of the oil to ensure it meets specifications

• Filter the oil to remove any impurities

• Fill the transformer with oil

• Test the transformer to ensure it is functioning properly

Yes, it is comfortable to transfer all over INDIA.

• As an electrical engineer, I am trained to work in various locations.

• I am adaptable and can easily adjust to different environments and cultures.

• I have experience working on projects in different states of India.

• I am willing to travel and relocate as required for the job.

MCB stands for Miniature Circuit Breaker. It is an electrical switch that automatically shuts off the electrical circuit during an overload or short circuit.

• MCB is a type of circuit breaker that is commonly used in residential and commercial buildings.

• It is designed to protect electrical circuits from damage caused by overloading or short circuits.

• MCBs are available in different current ratings and can be easily replaced if they trip.

• They are more reliable and faster in tripp...read more

Different types of sources of electricity include fossil fuels, nuclear power, renewable energy sources, and batteries.

• Fossil fuels (coal, oil, natural gas)

• Nuclear power

• Renewable energy sources (solar, wind, hydro, geothermal)

• Batteries (lithium-ion, lead-acid)

The number of wires that can be pulled through a 25mm conduit pipe depends on the size and type of the wires.

• The number of wires that can be pulled through a conduit pipe depends on the size of the wires and the size of the conduit pipe.

• Thinner wires will allow for more wires to be pulled through compared to thicker wires.

• For example, if using standard 2.5mm² wires, you may be able to pull around 4-6 wires through a 25mm conduit pipe.

Equipment required in HT and LT lines include transformers, circuit breakers, insulators, conductors, and lightning arresters.

• Transformers are used to step up or step down voltage levels in HT and LT lines.

• Circuit breakers are essential for protecting the lines from overloads and short circuits.

• Insulators are used to support and separate conductors to prevent electrical leakage.

• Conductors are used to carry the electrical current from one point to another.

• Lightning arresters p...read more

A Buchholz relay is a protective device used in oil-filled transformers to detect and prevent internal faults.

• Detects faults such as insulation breakdown or arcing within the transformer

• Consists of a float switch connected to an alarm or trip circuit

• When gas or oil accumulates due to a fault, the float rises and triggers the alarm or trip signal

• Helps prevent major damage to the transformer by isolating it from the power source

The ohmic value of PT-100 is 100 ohms at 0°C.

• PT-100 is a type of platinum resistance thermometer.

• It has a resistance of 100 ohms at 0°C.

• The resistance increases with temperature at a rate of 0.385 ohms/°C.

• PT-100 is commonly used in industrial temperature measurement applications.

Handing over taking over certificate is a document used in engineering projects to officially transfer responsibility from one party to another.

• It is a formal document that signifies the transfer of responsibility from one party to another in engineering projects.

• It includes details such as the scope of work, completion status, quality standards, and any outstanding issues.

• The certificate is signed by both parties to acknowledge the handover and acceptance of the project.

• It i...read more

Feeder bifurcation is the process of dividing a main electrical feeder into multiple branches to distribute power to different areas.

• Feeder bifurcation involves splitting a main feeder into smaller branches to supply power to different sections of a building or facility.

• This process helps in balancing the load and preventing overloading of the main feeder.

• Feeder bifurcation can be done using distribution panels, circuit breakers, and switches.

• Examples of feeder bifurcation in...read more

Railway crossings are intersections where roads and railway tracks meet, requiring vehicles to stop when trains are passing.

• Railway crossings are equipped with warning signs, lights, and barriers to alert drivers of approaching trains.

• Drivers must stop behind the barriers when they are down and wait for the train to pass before proceeding.

• Some railway crossings also have bells or horns to further warn drivers of an approaching train.

• It is important for drivers to always be ca...read more

Sensors in a turbine are located at various points to monitor temperature, pressure, vibration, and speed.

• Sensors are typically located at the inlet and outlet of the turbine to monitor temperature and pressure.

• Vibration sensors are placed on the turbine shaft to detect any abnormal vibrations that could indicate potential issues.

• Speed sensors are used to monitor the rotational speed of the turbine blades.

• Examples of sensors used in turbines include thermocouples, pressure tr...read more

The neutral wire and grounding serve different purposes in electrical systems.

• The neutral wire carries current back to the source in a balanced electrical circuit.

• Grounding provides a path for electrical faults to safely discharge into the ground.

• Neutral wire is typically connected to the center tap of a transformer, while grounding is connected to the earth.

• Neutral wire is part of the normal current-carrying circuit, while grounding is a safety measure to prevent electric sh...read more

A transformer is an electrical device that transfers electrical energy from one circuit to another through electromagnetic induction. Protection of transformer involves measures to prevent damage to the transformer due to various factors.

• Transformers are used to step up or step down voltage levels in power transmission and distribution systems.

• They consist of two coils, primary and secondary, wound around a common magnetic core.

• Protection of transformer involves measures such...read more

A substance has resistance due to the opposition it offers to the flow of electric current.

• Resistance is caused by collisions between electrons and atoms in the substance.

• The resistance of a substance depends on its physical properties such as length, cross-sectional area, and temperature.

• Some substances have higher resistance than others, such as insulators compared to conductors.

• Resistance can be measured in ohms using Ohm's law.

VBD test is conducted in transformers to ensure insulation integrity and detect any potential faults.

• VBD test helps in identifying any weak spots in the insulation of the transformer

• It helps in preventing breakdowns and ensuring the safety and reliability of the transformer

• By conducting VBD test, any potential faults can be detected early and necessary maintenance can be carried out

• It is a standard procedure in transformer testing to ensure optimal performance

I have worked with synchronous alternators and have experience in transformer maintenance.

• Worked with synchronous alternators in power generation applications

• Performed maintenance on transformers to ensure proper functioning

• Experience in troubleshooting and repairing electrical equipment

• Knowledge of safety protocols and regulations in electrical engineering

• Collaborated with team members to complete projects efficiently

Current is the flow of electric charge, while voltage is the force that drives the current.

• Current is the rate of flow of electric charge through a conductor.

• Voltage is the difference in electric potential between two points in a circuit.

• Current is measured in Amperes (A), while voltage is measured in Volts (V).

• Ohm's Law relates current, voltage, and resistance in a circuit: V = I * R.

• In a simple analogy, current is like the flow of water in a pipe, while voltage is like the ...read more

The natural role of my work as an Electrical Engineer is to design, develop, and maintain electrical systems and equipment.

• Designing electrical systems for buildings, power plants, or industrial facilities

• Developing electrical schematics and blueprints

• Testing and troubleshooting electrical equipment

• Ensuring compliance with safety standards and regulations

• Collaborating with other engineers and professionals on projects

• Providing technical support and guidance to clients or coll...read more

The heat producing components in this room include computers, servers, lighting fixtures, and HVAC systems.

• Computers

• Servers

• Lighting fixtures

• HVAC systems

Pulse width modulation (PWM) is a technique used in VFD to control the speed of the motor by adjusting the width of the pulses of voltage supplied to the motor.

• PWM is a method of controlling the amount of power delivered to a load without changing the voltage level.

• In VFD, PWM is used to control the speed of the motor by varying the width of the pulses of voltage supplied to the motor.

• The width of the pulses is controlled by a microprocessor that adjusts the frequency of the ...read more