900+ Electrical Engineer Interview Questions and Answers

Different types of cables are used in the industry depending on the specific application and requirements.

• Power cables are used to transmit electrical power from one point to another.

• Control cables are used to transmit control signals for operating machinery and equipment.

• Instrumentation cables are used for transmitting signals from sensors and instruments to control systems.

• Communication cables are used for data transmission in networking and telecommunications systems.

• Fiber...read more

Nitrogen gas is used in suspension cylinder to prevent foaming and cavitation.

• Nitrogen gas is used as a cushion to prevent the formation of air bubbles in the hydraulic fluid.

• It also prevents cavitation, which can cause damage to the cylinder and reduce its efficiency.

• Nitrogen gas is non-reactive and does not corrode the cylinder, making it a suitable choice for suspension systems.

• Examples of suspension systems that use nitrogen gas include shock absorbers in cars and hydraul...read more

Synchronisation process of a plant involves matching the frequency, voltage, and phase angle of the incoming generator with the grid.

• Ensure the generator frequency matches the grid frequency (50Hz or 60Hz).

• Match the voltage levels of the generator with the grid.

• Adjust the phase angle of the generator to synchronize with the grid.

• Use synchronizing equipment like synchroscope or synchronizing lamps to ensure proper synchronization.

• Once synchronized, close the circuit breaker to...read more

Single phase motors have one power phase while 3 phase motors have three power phases, resulting in differences in power output and efficiency.

• Single phase motors have lower power output compared to 3 phase motors.

• 3 phase motors are more efficient and have smoother operation.

• Single phase motors are commonly used in household appliances like fans and pumps, while 3 phase motors are used in industrial applications like pumps and compressors.

Fuses and circuit breakers are safety devices used to protect electrical circuits from overloads and short circuits.

• Fuses are designed to melt and break the circuit when there is an overload or short circuit, preventing damage to the circuit or equipment.

• Circuit breakers are switches that automatically trip when there is an overload or short circuit, cutting off the flow of electricity.

• Fuses need to be replaced after they have melted, while circuit breakers can be reset after...read more

Internal testing of transformers involves various tests to ensure proper functioning and safety.

• Insulation resistance test to check for any insulation breakdown

• Polarity test to verify correct connections

• Turns ratio test to ensure proper voltage transformation

• Winding resistance test to check for any short circuits or open circuits

• Impedance test to determine the impedance of the transformer

• Dielectric tests to assess the dielectric strength of the insulation material

ATS scheme stands for Automatic Transfer Switch scheme used in power systems.

• ATS scheme is used to transfer power supply from one source to another in case of power failure.

• It is commonly used in backup power systems to ensure uninterrupted power supply.

• ATS scheme can be implemented using mechanical or electronic switches.

• It is important to ensure proper coordination between the ATS and protective devices to avoid any damage to the system.

• Example: In a hospital, the ATS schem...read more

Yes, I am comfortable with mechanical maintenance.

• I have experience in troubleshooting and repairing mechanical equipment.

• I am familiar with mechanical systems such as pumps, motors, and conveyors.

• I have worked on projects that involved both electrical and mechanical components, and I understand how they interact with each other.

• I am willing to learn and adapt to new mechanical systems and technologies.

Improving product quality through safely implementing kaizen.

• Identify areas for improvement through data analysis and customer feedback.

• Involve all stakeholders in the kaizen process to ensure buy-in and collaboration.

• Implement changes gradually and monitor their effectiveness.

• Ensure safety measures are in place during the kaizen process to prevent accidents or injuries.

• Continuously evaluate and adjust the kaizen process to ensure sustained improvement.

• Example: Using kaizen t...read more

UPS provides backup power during power outages while an inverter converts DC to AC power.

• UPS provides instant backup power during power outages

• Inverter converts DC to AC power

• UPS has a battery backup system while inverters may or may not have one

• UPS is used for critical applications like hospitals, data centers, etc.

• Inverters are used for domestic purposes like powering home appliances, etc.

TRANSFRAMER is not a known term. DC GENERATOR is a device that converts mechanical energy into electrical energy.

• TRANSFRAMER is not a known term in electrical engineering

• DC GENERATOR is a device that converts mechanical energy into electrical energy

• DC generators are commonly used in power plants and electric vehicles

I have experience in both preventive and corrective maintenance of electrical machines.

• Performed regular inspections and cleaning of motors, transformers, and generators

• Replaced faulty components such as bearings, capacitors, and switches

• Diagnosed and repaired electrical faults in machines

• Implemented predictive maintenance techniques such as vibration analysis and thermography

• Maintained maintenance logs and records for future reference

Electrical motors are devices that convert electrical energy into mechanical energy. There are various types of electrical motors.

• DC motors - used in appliances, toys, and automobiles

• AC motors - used in industrial machinery and household appliances

• Stepper motors - used in robotics and automation

• Servo motors - used in precision control applications

• Brushless DC motors - used in drones and electric vehicles

Testing of protection relays involves verifying proper operation of the relays and ensuring correct interconnection of equipment through power and control cables.

• Perform functional testing of protection relays to ensure they operate correctly in response to fault conditions

• Verify proper interconnection of equipment by checking power and control cables for correct wiring and connections

• Use test equipment such as relay test sets and multimeters to perform testing and troublesho...read more

Electricity is the flow of electric charge through a conductor.

• Electricity is the movement of electrons or other charged particles.

• It is a form of energy that can be generated, transmitted, and used for various purposes.

• Electricity can be produced by chemical reactions, electromagnetic induction, or photovoltaic cells.

• Examples of electricity include the power supplied to homes and businesses, lightning, and electric currents in electronic devices.

Power distribution is the process of delivering electricity from power plants to consumers through a network of transmission and distribution lines.

• Electricity is generated at power plants using various sources such as coal, natural gas, nuclear, or renewable energy.

• The electricity is then transmitted at high voltages over long distances through transmission lines to substations.

• At substations, the voltage is reduced and the electricity is distributed through distribution lin...read more

A magger is a device used to measure the insulation resistance of electrical equipment or cables.

• Magger machine is also known as insulation tester.

• It is used to check the insulation resistance of electrical systems to ensure safety and prevent electrical failures.

• The machine applies a high voltage to the equipment and measures the resistance to current flow, indicating the condition of the insulation.

• Regular testing with a magger can help identify potential issues before they...read more

A single line diagram is a simplified diagram that shows the electrical connections and components of a power system using single lines.

• It is a simplified representation of a power system, showing the main components and their interconnections using single lines.

• It is used by electrical engineers to understand and analyze the power system without getting into the details of each individual component.

• It typically includes generators, transformers, circuit breakers, switches, a...read more

Typically, 12 or 14 gauge wire is used for house wiring.

• 12 or 14 gauge wire is commonly used for general house wiring

• Thicker wire (lower gauge number) is used for higher current applications like kitchen appliances

• Thinner wire (higher gauge number) is used for lighting and general outlets

The two types of motors generally used in plants are AC motors and DC motors.

• AC motors are commonly used for high-power applications and are more efficient.

• DC motors are often used for low-power applications and provide better speed control.

• Examples of AC motors include induction motors and synchronous motors.

• Examples of DC motors include brushed DC motors and brushless DC motors.

PLC and HMI can communicate through various protocols such as Ethernet/IP, Modbus, Profibus, etc.

• PLC and HMI can be connected through a physical cable or wireless connection

• PLC sends data to HMI through the chosen protocol

• HMI displays the data received from PLC and sends commands back to PLC

• Programming software is used to configure the communication settings

• Examples of protocols used for communication are Ethernet/IP, Modbus, Profibus, etc.

Slip-ring motor speed can be controlled by varying the resistance in the rotor circuit.

• Slip-ring motors have a wound rotor with external resistors.

• By changing the resistance in the rotor circuit, the speed can be controlled.

• This is done by adding or removing resistors from the rotor circuit.

• The speed can also be controlled by changing the voltage applied to the stator.

• This method is commonly used in industries where variable speed is required, such as in cranes and hoists.

A PLC ladder program for star delta connection

• Create a new ladder program in the PLC software

• Define the inputs and outputs for the program

• Write the ladder logic for the star delta connection

• Test the program to ensure proper functionality

I am a qualified Electrical Engineer with experience in the field and seeking a new opportunity.

• Name: [Insert Name]

• Qualifications: Electrical Engineering degree

• Department: [Insert Department]

• Experience: [Insert Years of Experience]

• Current Ctc: [Insert Current Salary]

• Expected Ctc: [Insert Expected Salary]

Safety PPE used in plants include hard hats, safety glasses, gloves, and steel-toed boots.

• Hard hats protect the head from falling objects and electrical hazards.

• Safety glasses protect the eyes from flying debris and chemicals.

• Gloves protect the hands from cuts, burns, and chemical exposure.

• Steel-toed boots protect the feet from heavy objects and electrical hazards.

• Other PPE may include respirators, hearing protection, and reflective vests.

• PPE should be worn at all times in de...read more

The yawing system is a mechanism used to control the yaw motion of a vehicle or aircraft.

• The yawing system typically consists of a rudder or ailerons, control surfaces that are used to change the direction of the vehicle or aircraft.

• In aircraft, the yawing system is responsible for controlling the side-to-side movement of the nose of the aircraft.

• In vehicles, the yawing system helps in maintaining stability and controlling the direction of the vehicle during turns.

• The yawing ...read more

DFIG stands for Doubly Fed Induction Generator, a type of wind turbine generator system.

• DFIG system is a type of wind turbine generator system

• It uses a wound rotor induction generator with a partial power electronic converter

• The converter controls the rotor current and allows for variable speed operation

• DFIG system is more efficient and cost-effective than other wind turbine systems

• It is commonly used in wind farms and renewable energy projects

Safety interlock for HT motor starting ensures safe operation by preventing accidental starting or unauthorized access.

• Safety interlock system is designed to prevent the motor from starting if certain conditions are not met.

• It typically includes sensors, switches, and control logic to monitor and control the starting process.

• Examples of safety interlock features include door interlocks, emergency stop buttons, and motor overload protection.

• Interlocks can also be integrated wi...read more

Preventive maintenance (PM) is the regular inspection and servicing of equipment to prevent breakdowns.

• Preventive maintenance is a proactive approach to ensure the reliability and longevity of electrical equipment.

• During PM, equipment is inspected, cleaned, lubricated, and calibrated as necessary.

• Common tasks during PM include checking for loose connections, testing electrical components, and replacing worn-out parts.

• PM helps identify potential issues before they cause major ...read more

Managing employees involves setting clear expectations, providing feedback, recognizing achievements, and fostering a positive work environment.

• Set clear expectations and goals for each employee

• Provide regular feedback and constructive criticism

• Recognize and reward achievements and good performance

• Foster a positive work environment through open communication and team building activities

• Address any issues or conflicts promptly and fairly

The best method in power transfers is through high voltage transmission lines.

• High voltage transmission lines are more efficient in transferring power over long distances.

• Using transformers to step up the voltage before transmission and step down the voltage at the receiving end helps minimize power loss.

• HVDC (High Voltage Direct Current) transmission is another efficient method for long distance power transfers.

• Smart grid technologies can also optimize power transfers by mon...read more

The parameters of Mitsubishi drive refer to the specific settings and characteristics that can be adjusted and controlled for optimal performance.

• Parameters include variables such as speed, torque, acceleration, deceleration, and control modes.

• For example, the speed parameter determines the maximum rotational speed of the drive.

• Torque parameter controls the amount of rotational force the drive can generate.

• Acceleration and deceleration parameters define how quickly the drive ...read more

MCB stands for Miniature Circuit Breaker. It is an electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit.

• MCB is a type of circuit breaker that automatically switches off electrical circuits during abnormal conditions like overload or short circuit.

• It is a small device that can be easily reset after tripping, unlike a fuse which needs to be replaced.

• MCBs come in different ratings to protect circuits of varying capacities.

• Th...read more

Calibration 3.0 and 5.0 refer to the accuracy level of a measuring instrument.

• Calibration 3.0 means the instrument has an accuracy level of 0.3% of the full scale reading.

• Calibration 5.0 means the instrument has an accuracy level of 0.5% of the full scale reading.

• The higher the calibration number, the more accurate the instrument is.

• Calibration is the process of adjusting an instrument to ensure its accuracy.

• Calibration is important in industries such as manufacturing, aerosp...read more

Transformer operates on the principle of electromagnetic induction to transfer electrical energy between two or more circuits.

• Transformers have two coils, primary and secondary, which are magnetically coupled but electrically isolated.

• When an alternating current flows through the primary coil, it creates a changing magnetic field which induces a voltage in the secondary coil.

• The ratio of the number of turns in the primary coil to the number of turns in the secondary coil dete...read more

Power generation equipment includes generators, turbines, and transformers for producing electricity.

• Generators convert mechanical energy into electrical energy

• Turbines use steam, water, or wind to rotate a shaft connected to a generator

• Transformers increase or decrease voltage for efficient transmission and distribution

• Examples: gas turbines, hydroelectric generators, step-up transformers

Various protocols used in automation include Modbus, Profibus, Ethernet/IP, and DeviceNet.

• Modbus: Widely used for serial communication between devices in industrial automation.

• Profibus: Commonly used in process automation for communication between field devices and controllers.

• Ethernet/IP: Utilized for real-time control and information sharing in industrial automation.

• DeviceNet: Used for connecting industrial devices in a network for data exchange.

Types of solar plants include photovoltaic, concentrated solar power, and solar thermal. Solar panels can be monocrystalline, polycrystalline, or thin-film.

• Types of solar plants: photovoltaic, concentrated solar power, solar thermal

• Types of solar panels: monocrystalline, polycrystalline, thin-film

• Applications: residential, commercial, utility-scale

• Examples: Ivanpah Solar Power Facility (concentrated solar power), SolarCity (photovoltaic)

• Solar panels convert sunlight into elec...read more

Phase voltage for 220kV is approximately 127kV.

• Phase voltage is the voltage between any one phase and the neutral point in a three-phase system.

• For a 220kV system, the phase voltage can be calculated using the formula: Phase Voltage = Line Voltage / √3.

• In this case, Line Voltage = 220kV, so Phase Voltage ≈ 220kV / √3 ≈ 127kV.

The erection of an 11 kV line involves setting up a power line infrastructure for transmitting electricity over a distance of 1 km.

• Materials required include conductors (such as aluminum or copper), insulators, poles, transformers, and hardware fittings.

• The conductors are used to carry the electricity from one point to another, while insulators prevent the flow of electricity to the ground.

• Poles are used to support the conductors and keep them at a safe distance from the grou...read more

VFD stands for Variable Frequency Drive.

• VFD is an electronic device that controls the speed of an AC motor by varying the frequency of the electrical power supplied to the motor.

• It is commonly used in industrial and commercial applications to save energy and improve process control.

• VFDs can also improve motor performance and extend the life of the motor.

• Examples of VFD applications include HVAC systems, pumps, fans, and conveyors.

To reduce breakdown, proper maintenance, regular inspections, and implementing safety measures are essential.

• Perform regular maintenance and inspections to identify and address potential issues before they lead to breakdowns.

• Implement safety measures such as overload protection, surge protection, and grounding to prevent breakdowns caused by electrical faults.

• Ensure proper installation and wiring to minimize the risk of breakdowns.

• Use high-quality components and equipment to ...read more

Bypassing an ACB breaker involves isolating the breaker and connecting the load directly to the power source.

• Isolate the ACB breaker by opening the circuit and locking it in the open position

• Connect the load directly to the power source using a temporary cable

• Ensure that the temporary cable is rated for the load and is properly grounded

• Test the load to ensure that it is functioning properly before removing the temporary cable

• Reconnect the load to the ACB breaker once it has b...read more

The current in a DC-DC converter is converted from one voltage level to another while maintaining power conservation.

• The current in a DC-DC converter is typically stepped up or stepped down to achieve the desired output voltage.

• The conversion process involves switching elements like transistors to control the flow of current and voltage.

• Efficiency of the converter is crucial to minimize power losses during the conversion process.

• Examples of DC-DC converters include buck conve...read more

F.left hand theorem states that the magnetic field around a current-carrying conductor can be determined using the left hand rule.

• States that if the thumb, forefinger, and middle finger of the left hand are extended at right angles to each other, with the forefinger pointing in the direction of the current, the thumb in the direction of the magnetic field, then the middle finger points in the direction of the force experienced by a positive charge.

• Used to determine the direct...read more

To reduce overload on a distribution network, implement demand response programs, upgrade infrastructure, and utilize energy storage.

• Implement demand response programs to manage peak loads by incentivizing consumers to reduce electricity usage during high demand periods.

• Upgrade infrastructure by installing smart grid technologies, such as advanced metering systems and distribution automation, to improve network efficiency and reliability.

• Utilize energy storage solutions, such...read more

I am proficient in using software such as AutoCAD, MATLAB, and LabVIEW for electrical engineering tasks.

• AutoCAD for designing electrical systems and circuits

• MATLAB for analyzing and simulating electrical systems

• LabVIEW for data acquisition and control systems