1000+ Electrical Engineer Interview Questions and Answers

Feeder charging and handing over involves the process of transferring electrical power from one source to another.

• Ensure proper safety measures are in place before starting the process

• Check the voltage and current ratings of the feeder to ensure compatibility with the receiving end

• Disconnect the feeder from the power source and connect it to the receiving end

• Verify the successful transfer of power and ensure proper functioning of the system

• Complete necessary documentation and...read more

Earthing road is used in HT lines to provide a path for fault current to flow safely into the ground, preventing damage to equipment and ensuring safety.

• Earthing road is a conductive strip or wire buried in the ground near HT lines.

• It provides a low resistance path for fault current to flow into the ground, preventing damage to equipment and ensuring safety.

• Proper installation of earthing road involves burying the conductor at a sufficient depth below the surface to ensure go...read more

Yes, I can draw a single line diagram of s/d starter.

• A single line diagram shows the electrical connections and components in a simplified manner.

• For an s/d starter, the diagram would include the power supply, motor, overload relay, and contactor.

• The diagram would also show the control circuit components such as push buttons and switches.

• The diagram should follow standard symbols and conventions for electrical diagrams.

• An example of a single line diagram for an s/d starter ca...read more

Yes, I have experience managing spare parts and their records and documents.

• I have previously managed spare parts and their records and documents in my previous job.

• I am familiar with inventory management software and can use it to keep track of spare parts.

• I can create and maintain a database of spare parts, including their specifications, purchase dates, and maintenance history.

• I can also ensure that all necessary documentation, such as manuals and warranties, are properly ...read more

The erection of E&I equipment involves the installation and assembly of electrical and instrumentation components.

• Erection of E&I equipment includes the installation of electrical panels, cables, and wiring.

• It also involves the assembly of instrumentation devices such as sensors, transmitters, and control systems.

• Proper grounding and bonding techniques are essential during the erection process.

• Testing and commissioning of the equipment is done to ensure functionality and safe...read more

A current transformer is a device that measures the current flowing in a circuit by producing a proportional current in its secondary winding.

• Consists of a primary winding and a secondary winding

• Primary winding is connected in series with the circuit carrying the current to be measured

• Secondary winding is connected to a measuring instrument or protective relay

• Produces a current in the secondary winding that is proportional to the current in the primary winding

• Used for current...read more

A rectifier is an electrical device that converts alternating current (AC) to direct current (DC). Three-phase connection refers to a system that uses three conductors to carry three alternating currents that are out of phase with each other.

• Rectifiers are commonly used in power supplies and electronic devices to convert AC to DC.

• Three-phase connections are used in industrial and commercial settings to power large motors and equipment.

• Three-phase power is more efficient and p...read more

The number of transformer ratings required for 50 households depends on their power consumption and distribution network.

• The power consumption of each household needs to be determined

• The distribution network and voltage level also affect the transformer rating

• Assuming an average power consumption of 1 kW per household, a 50 kW transformer may be required

• However, this can vary greatly depending on the specific circumstances

Different types of motors are used in different applications based on their characteristics and requirements.

• Select motor type based on application requirements (e.g. AC motor for household appliances, DC motor for automotive applications)

• Consider factors like speed, torque, power, efficiency, and control method when choosing a motor

• Use stepper motors for precise positioning in robotics and CNC machines

• Utilize servo motors for applications requiring high precision and control...read more

PLCs are used in industrial areas for real-time control and automation, while SCADA systems are used for monitoring and data acquisition.

• PLCs are designed for real-time control of machinery and processes in industrial settings.

• PLCs are more reliable and robust for controlling critical processes compared to SCADA systems.

• SCADA systems are typically used for monitoring and data acquisition in industrial settings.

• PLCs are better suited for controlling discrete and continuous pro...read more

The repeated burning of a 22 kW AOP motor CT cable may be due to overloading, short circuits, poor insulation, or incorrect cable sizing.

• Check for overloading of the motor causing excessive heat in the cable

• Inspect for short circuits in the motor or the wiring

• Ensure proper insulation of the cable to prevent overheating

• Verify if the cable size is appropriate for the motor's power requirements

Bypassing the CT of an AOP motor can lead to overcurrent and damage to the motor.

• Bypassing the CT can result in the motor drawing excessive current.

• This can lead to overheating of the motor windings.

• Overcurrent can cause damage to the motor components.

• It can also pose a safety risk due to potential electrical faults.

The material used in transformers is typically iron or steel.

• Transformers use a magnetic core made of laminated iron or steel sheets to increase efficiency.

• The core material is chosen for its magnetic properties and ability to withstand high temperatures.

• Other materials such as ferrite or amorphous metal may also be used in certain types of transformers.

• The winding material for the coils is typically copper or aluminum wire.

CT sizing is done by considering the primary current, burden, and accuracy class of the CT.

• Determine the primary current of the system

• Calculate the burden of the CT

• Select the accuracy class of the CT

• Use the formula: CT rating = primary current x burden / (accuracy class x 100)

• Example: For a 400A primary current, 5VA burden, and 0.5 accuracy class, CT rating = 400 x 5 / (0.5 x 100) = 40A

Transformers, bushings, relays, and buck converters are all electrical components used in power systems.

• Transformers are devices that transfer electrical energy from one circuit to another through electromagnetic induction.

• Bushings are insulating structures that allow electrical conductors to pass through walls or barriers without allowing current to leak.

• Relays are switches that are operated electrically and used to control circuits by opening and closing contacts in respons...read more

To design and add lighting in a 59*50 room, consider the room's purpose, lighting requirements, and energy efficiency.

• Determine the purpose of the room and the activities that will take place in it.

• Calculate the required lighting levels based on the room's function and recommended standards.

• Consider the room's layout and identify areas that need focused lighting, such as workstations or reading corners.

• Choose appropriate lighting fixtures, such as recessed lights, pendant lig...read more

The SLD (Single Line Diagram) is a graphical representation of the electrical system of a plant.

• SLD shows the electrical components and their interconnections in a simplified manner.

• It helps in understanding the power flow and control of the plant.

• SLD includes transformers, generators, switchgear, motors, and other electrical equipment.

• It also depicts protection devices, control circuits, and communication systems.

• SLD is essential for troubleshooting, maintenance, and design ...read more

The max carrier frequency of Yaskawa A1000 is 16kHz. Department ISO objective and MD calculation time are not related to the product.

• Max carrier frequency of Yaskawa A1000 is 16kHz

• Department ISO objective is not related to the product

• MD calculation time is not related to the product

The power plug earth wire is bigger in size to ensure safety and prevent electrical shocks.

• The earth wire provides a path for the current to flow in case of a fault or short circuit.

• A larger wire size reduces resistance and allows for the safe dissipation of excess current.

• It helps to protect individuals and equipment from electric shock hazards.

• The earth wire is connected to the ground, which acts as a reference point for electrical potential.

• Examples of larger earth wire si...read more

Solar panel installation requires several components including solar panels, inverters, mounting systems, wiring, and electrical protection devices.

• Solar panels: These are the main components that convert sunlight into electricity.

• Inverters: They convert the direct current (DC) produced by solar panels into alternating current (AC) that can be used in homes or fed into the grid.

• Mounting systems: These are used to securely install the solar panels on rooftops or ground-mounted...read more

There are various types of circuit breakers with different uses and ratings.

• Miniature Circuit Breaker (MCB) - used in residential and commercial buildings

• Molded Case Circuit Breaker (MCCB) - used in industrial applications

• Air Circuit Breaker (ACB) - used for high voltage applications

• Ground Fault Circuit Interrupter (GFCI) - used to protect against electrical shocks

• Residual Current Circuit Breaker (RCCB) - used to detect ground faults

• Vacuum Circuit Breaker (VCB) - used in medi...read more

There is no such thing as pawar transfarmer.

Compressor in AC is used to compress the refrigerant gas and increase its temperature and pressure.

• Compressor is the heart of an AC system.

• It compresses the low-pressure refrigerant gas into high-pressure gas.

• This high-pressure gas then flows through the condenser where it releases heat and becomes a high-pressure liquid.

• The liquid then flows through the expansion valve where it expands and becomes a low-pressure liquid.

• This low-pressure liquid then flows through the evaporat...read more

Ten delta test is used to detect winding deformation and shorted turns in transformer.

• Detects winding deformation and shorted turns

• Helps in identifying internal faults

• Used for routine maintenance and troubleshooting

Copper and aluminum are commonly used conductors in transmission.

• Copper is an excellent conductor due to its high electrical conductivity.

• Aluminum is also widely used as it is lightweight and cost-effective.

• Other conductors like silver and gold are rarely used due to their high cost.

• Copper-clad steel conductors are used in specific applications where strength is required.

I have handled testing of various electrical equipment including transformers, switchgears, motors, generators, and control panels.

• Testing of transformers for insulation resistance, winding resistance, turns ratio, and polarity

• Testing of switchgears for insulation resistance, contact resistance, and operation

• Testing of motors for insulation resistance, winding resistance, and no-load and load testing

• Testing of generators for insulation resistance, winding resistance, and load...read more

Field tests required before commissioning of power transformers include insulation resistance test, turns ratio test, and polarity test.

• Insulation resistance test is conducted to ensure the insulation system is intact and can withstand the operating voltage.

• Turns ratio test is performed to verify the turns ratio of the transformer and ensure it meets the design specifications.

• Polarity test is carried out to confirm the correct connection of primary and secondary windings.

• Othe...read more

Power transformers require various protection measures to ensure their safe and reliable operation.

• Overcurrent protection to prevent excessive current flow

• Differential protection to detect internal faults

• Buchholz relay to detect and prevent transformer oil and gas faults

• Temperature monitoring to prevent overheating

• Voltage protection to safeguard against overvoltage

• Ground fault protection to detect and isolate ground faults

• Winding temperature indicators to monitor winding temp...read more

When two positively charged materials are placed together, they repel each other.

• The two materials will experience a repulsive force.

• The strength of the force will depend on the magnitude of the charges and the distance between them.

• This phenomenon is explained by Coulomb's law.

• Examples include two positively charged balloons or two positively charged metal spheres.

Equal area criteria is a method to determine stability of power systems.

• It is used to analyze transient stability of power systems.

• It states that for a power system to be stable, the area of the power-angle curve during fault should be equal to the area of the power-angle curve after fault clearance.

• It helps in determining the critical clearing angle and time required for fault clearance.

• It is based on the assumption that the power system can be represented by a swing equatio...read more

JMC stands for Joint Measurement Committee and BOQ stands for Bill of Quantities.

• JMC is a committee that is responsible for measuring the quantities of materials used in construction projects.

• BOQ is a document that lists all the materials, parts, and labor required for a construction project.

• BOQ is used to estimate the cost of a project and to ensure that all necessary materials and labor are accounted for.

• JMC and BOQ are important tools for ensuring that construction project...read more

Hazardous areas are classified based on the presence of flammable gases, vapors, liquids, or combustible dusts.

• Hazardous areas are classified into different zones based on the likelihood and duration of the presence of hazardous substances.

• The classification is important for designing and installing electrical equipment that can operate safely in these areas.

• The classification systems vary depending on the country or region, but commonly used classifications include the IECEx...read more

Copper is a material with high conductivity.

• Copper is widely used in electrical wiring due to its high conductivity.

• Silver is another material with high conductivity, but it is more expensive than copper.

• Aluminum is also a good conductor, but it has lower conductivity compared to copper.

AC systems alternate the direction of current flow, while DC systems have a constant flow in one direction.

• AC systems change the direction of current flow periodically, typically at 50 or 60 Hz.

• DC systems have a constant flow of current in one direction.

• AC is used for long-distance power transmission, while DC is used for shorter distances and in electronic devices.

• Examples of AC systems include power grids and household outlets, while examples of DC systems include batteries...read more

FRLS cables are not used in place of FLP cables due to differences in their fire safety properties and applications.

• FRLS cables are Flame Retardant Low Smoke cables designed to reduce the spread of fire and emit less smoke when burned.

• FLP cables are Flameproof cables designed to contain any explosion within the cable, making them suitable for hazardous environments.

• The choice between FRLS and FLP cables depends on the specific requirements of the application in terms of fire ...read more

Different types of communication cables used in the electrical engineering industry include coaxial cables, twisted pair cables, and fiber optic cables.

• Coaxial cables: used for high-frequency transmission and commonly used in cable television and computer networks.

• Twisted pair cables: consists of pairs of insulated copper wires twisted together to reduce electromagnetic interference, commonly used in Ethernet networks.

• Fiber optic cables: use light pulses to transmit data and ...read more

To communicate S7 PLC and ABB drive using Profibus, you need to configure the Profibus network, set up the communication parameters, and establish the communication link.

• Configure the Profibus network by setting the correct baud rate, address, and other network parameters.

• Set up the communication parameters on both the S7 PLC and ABB drive to ensure they are compatible with each other.

• Establish the communication link by configuring the input and output data exchange between t...read more

The main safety in circuit breakers in HT and LT line is to protect the electrical equipment from overloading and short circuits.

• Circuit breakers are designed to trip and disconnect the power supply when there is an overload or short circuit in the electrical system.

• In HT line, circuit breakers are equipped with high voltage insulation to prevent electrical arcing and ensure safety.

• In LT line, circuit breakers are designed to trip quickly to prevent damage to the electrical e...read more

A generator is a device that converts mechanical energy into electrical energy.

• Generators work on the principle of electromagnetic induction.

• A conductor is rotated in a magnetic field, which induces an electrical current in the conductor.

• The mechanical energy required to rotate the conductor can come from various sources such as steam turbines, water turbines, or internal combustion engines.

• Generators are used in power plants, wind turbines, and portable devices such as RVs a...read more

A motor is a device that converts electrical energy into mechanical energy to produce motion.

• Motors are used in various applications such as electric vehicles, industrial machinery, and household appliances.

• There are different types of motors such as DC motors, AC motors, stepper motors, and servo motors.

• The basic principle of a motor is the interaction between a magnetic field and an electric current.

• Examples of motors include ceiling fans, washing machines, and electric car...read more

My final year project was designing a smart grid system for efficient energy distribution.

• Developed a system to monitor and control electricity distribution in real-time

• Implemented renewable energy sources integration for sustainability

• Optimized energy usage and reduced wastage through smart grid technology

• Benefits include improved reliability, reduced costs, and environmental sustainability

The health of a transformer can be determined by analyzing its insulation, oil quality, and temperature.

• Check insulation resistance using a megohmmeter

• Analyze oil quality for signs of degradation or contamination

• Monitor temperature to ensure it stays within safe operating limits

• Perform regular maintenance and testing to detect any issues early

• Consider using online monitoring systems for continuous monitoring

• Look for signs of physical damage or corrosion on the transformer

• Chec...read more

The primary winding is the first coil in a transformer that receives electrical energy.

• The primary winding is typically connected to the power source.

• It is responsible for receiving and transmitting electrical energy to the secondary winding.

• The number of turns in the primary winding determines the voltage ratio between the primary and secondary sides.

• Primary windings are commonly found in transformers, induction motors, and other electrical devices.

A characteristic of digital signal is that it is discrete and represented by binary numbers.

• Digital signals are represented by discrete values

• Digital signals are represented by binary numbers (0s and 1s)

• Digital signals are less susceptible to noise compared to analog signals

3-phase induction motor slip ring and squirrel cage motor differ in rotor construction and starting torque.

• Slip ring motor has external resistors and brushes to control rotor current and torque, while squirrel cage motor has a simple rotor with copper bars.

• Slip ring motor has high starting torque and is used in heavy load applications like cranes and elevators, while squirrel cage motor has low starting torque and is used in fans and pumps.

• Slip ring motor is more expensive an...read more

Power transmission lines carry high voltage power from power plants to substations while distribution lines carry lower voltage power from substations to homes and businesses.

• Power transmission lines carry high voltage power over long distances

• Distribution lines carry lower voltage power over shorter distances

• Transmission lines use high voltage to reduce energy loss during long distance transmission

• Distribution lines use transformers to step down voltage for use in homes and ...read more

Slip ring motors use external resistors for starting and speed control, while squirrel cage motors rely on the number of poles and frequency for speed control.

• Slip ring motors have external resistors that are gradually removed to increase speed

• Squirrel cage motors rely on the number of poles and frequency for speed control

• Slip ring motors are used in applications where high starting torque is required

• Squirrel cage motors are used in applications where constant speed is requir...read more