900+ Electrical Engineer Interview Questions and Answers

A control system of an electric panel is a system that regulates and manages the operation of electrical components within the panel.

• Control systems in electric panels can include programmable logic controllers (PLCs) to automate processes.

• They can also involve relays, switches, and sensors to monitor and control the flow of electricity.

• Control systems ensure the safety, efficiency, and functionality of the electric panel.

• Examples of control systems in electric panels include...read more

Active components require a power source to operate, while passive components do not.

• Active components require an external power source to function, such as transistors and integrated circuits.

• Passive components do not require an external power source, such as resistors and capacitors.

• Active components can control the flow of electricity, while passive components simply store or dissipate energy.

• Examples of active components include diodes, transistors, and operational amplif...read more

EOt crane is an electric overhead traveling crane used for lifting and moving heavy loads in industrial settings.

• EOt stands for Electric Overhead Traveling

• It is operated by an electrical control system

• It consists of a bridge, hoist, trolley, and electrical components

• It is commonly used in factories, warehouses, and construction sites

• It can lift and move heavy loads up to several tons

• It requires regular maintenance and safety checks

Wire current capacity can be calculated using the wire gauge and the maximum current rating of the wire.

• Determine the wire gauge

• Refer to the maximum current rating chart for the wire gauge

• Consider the length of the wire and the ambient temperature

• Use the appropriate formula to calculate the current capacity

Capacitors store electrical energy and release it when needed.

• Capacitors are used in electronic circuits to filter out noise and stabilize voltage.

• They are also used in timing circuits, oscillators, and power factor correction.

• Capacitors can be found in various electronic devices such as TVs, computers, and smartphones.

• They are also used in power grids to improve power quality and efficiency.

• Capacitors come in different types and sizes, each with its own specific use and char...read more

SCR and TRIAC are semiconductor devices used for switching and controlling power in electronic circuits.

• SCR stands for Silicon Controlled Rectifier and is a four-layer PNPN semiconductor device used for power control applications.

• TRIAC stands for Triode for Alternating Current and is a three-layer PNPN semiconductor device used for AC power control applications.

• Both devices work by controlling the flow of current through them using a gate signal.

• SCR is a unidirectional device...read more

Buccholz relay is a protective device used in oil-filled transformers to detect faults such as internal arcing or overheating.

• Buccholz relay is installed in the oil pipe connecting the transformer tank and conservator tank.

• It works based on the principle that gas is generated when a fault occurs in the transformer, causing oil level to drop and gas to accumulate in the relay.

• The relay consists of two float switches - one for oil level and one for gas accumulation, which trigg...read more

To check an electrical tester, follow these steps:

• Ensure the tester is properly calibrated

• Check the battery level and replace if necessary

• Test the tester on a known live circuit

• Verify that the tester gives the expected readings

• Inspect the tester for any physical damage or loose connections

A measuring instrument is a device used to measure physical quantities such as length, temperature, pressure, and voltage.

• Measuring instruments are used in various fields such as engineering, physics, and chemistry.

• Examples of measuring instruments include rulers, thermometers, pressure gauges, and voltmeters.

• Measuring instruments can be analog or digital, and can have varying degrees of accuracy.

• Calibration is important to ensure the accuracy of measuring instruments.

• Measuri...read more

Transformers are rated in KVA because they are designed to handle both real power (KW) and reactive power (KVAR).

• KVA represents the apparent power of the transformer, which is the combination of real power (KW) and reactive power (KVAR).

• Reactive power is necessary for the magnetization of the transformer's core and does not contribute to useful work.

• The rating in KVA ensures that the transformer can handle both the real and reactive power demands of the load.

• For example, a tr...read more

Glands are used to provide a secure and watertight seal in electrical systems. Voltage drop occurs due to resistance in the electrical circuit.

• Glands are used to prevent the entry of dust, moisture, and other contaminants into electrical enclosures or equipment.

• They provide a secure and watertight seal around cables or wires, ensuring the safety and reliability of the electrical system.

• Glands are commonly used in outdoor or harsh environments where protection against environm...read more

Types of transformer construction and substation equipments are fundamental in electrical engineering.

• Types of transformer construction include core type, shell type, and winding type.

• Substation equipments include circuit breakers, transformers, busbars, and insulators.

• Different types of transformers are used in substations based on voltage levels and power requirements.

The minimum insulation resistance value for a Lt Motor.

• The minimum insulation resistance value for a Lt Motor is typically 1 Megaohm.

• This value is important to ensure the motor is properly insulated and protected from electrical faults.

• Insulation resistance can be measured using a megohmmeter.

• Factors that can affect insulation resistance include temperature, humidity, and contamination.

• Regular testing of insulation resistance is important for preventative maintenance and safe...read more

As an Electrical Engineer, my responsibility within the plant includes designing, testing, and maintaining electrical systems to ensure smooth operations.

• Designing electrical systems for optimal plant operations

• Testing and troubleshooting electrical equipment to ensure functionality

• Maintaining electrical systems to prevent downtime and ensure safety

• Collaborating with other engineers and plant personnel to address electrical issues

• Implementing energy efficiency measures to red...read more

Transformer cooling can be of various types depending on the application and design requirements.

• Transformer cooling can be achieved through methods such as air cooling, oil cooling, and water cooling.

• Air cooling involves the use of fans or natural convection to dissipate heat from the transformer.

• Oil cooling utilizes a transformer oil that circulates through the transformer, absorbing and dissipating heat.

• Water cooling involves the use of water as a cooling medium, either th...read more

There are several types of earthing used in electrical engineering.

• The most common types of earthing are:

• - TN-S system: separate neutral and protective earth

• - TN-C system: combined neutral and protective earth

• - TN-C-S system: combination of TN-S and TN-C systems

• - TT system: separate earth for each electrical installation

• - IT system: no direct connection to earth, relies on insulation monitoring

• Other types include:

• - TN-R system: neutral is directly earthed at source

• - TN-B syst...read more

HT panel works on auxiliary supply or DC supply.

• HT panel stands for High Tension panel.

• It is used in electrical power systems to control and distribute high voltage power.

• The working of HT panel depends on the type of supply it is designed for.

• In some cases, HT panels are designed to work on auxiliary supply, which is typically AC power from a backup generator or an external source.

• In other cases, HT panels are designed to work on DC supply, which is typically provided by bat...read more

Transformer earthing types include solid earthing, resistance earthing, and reactance earthing. The size of the transformer neutral earthing conductor depends on the transformer rating.

• Solid earthing involves connecting the transformer neutral directly to the earth

• Resistance earthing involves connecting a resistor between the transformer neutral and earth

• Reactance earthing involves connecting a reactor between the transformer neutral and earth

• The size of the transformer neutr...read more

Data structure is a way of organizing and storing data in a computer so that it can be accessed and manipulated efficiently.

• Data structures define the way data is organized and stored in memory.

• They provide efficient algorithms for accessing, inserting, and deleting data.

• Examples of data structures include arrays, linked lists, stacks, queues, trees, and graphs.

Transistors are electronic devices used to amplify or switch electronic signals. There are two types: bipolar junction transistors and field-effect transistors.

• Transistors are made of semiconductor materials such as silicon or germanium.

• Bipolar junction transistors have three regions: emitter, base, and collector.

• Field-effect transistors have three terminals: source, gate, and drain.

• Transistors are used in various electronic devices such as amplifiers, switches, and oscillato...read more

AHU in chiller is appreciated for its ability to regulate temperature and humidity levels.

• AHU stands for Air Handling Unit

• AHU in chiller helps in maintaining the desired temperature and humidity levels in the building

• It also helps in improving indoor air quality by filtering out pollutants and allergens

• AHU can be customized to meet specific requirements of the building

• Proper maintenance of AHU is crucial for its efficient functioning

Synchronising of a generator is the process of matching its speed and voltage with the grid before connecting it.

• Synchronising is necessary to avoid damage to the generator and the grid.

• It involves adjusting the speed and voltage of the generator to match that of the grid.

• Synchronising can be done manually or automatically using synchronising relays.

• Once synchronised, the generator can be connected to the grid and start supplying power.

• If not done properly, synchronising can ...read more

An inverter is a device that converts DC power to AC power.

• An inverter is commonly used in electrical systems to convert the direct current (DC) produced by sources such as batteries or solar panels into alternating current (AC) that can be used to power appliances and devices.

• The basic working principle of an inverter involves the use of electronic components such as transistors to switch the DC input on and off rapidly, creating a square wave or modified sine wave output.

• Th...read more

The question is asking about the work and testing of a transformer, inverter, PV array, and MMS in an electrical engineering context.

• Transfomer: Explain the function of a transformer in electrical systems, mention testing methods like turns ratio test and insulation resistance test.

• Inverter: Describe how an inverter converts DC power to AC power, discuss testing procedures such as efficiency testing and harmonic distortion analysis.

• PV Array: Explain the role of a PV array in ...read more

LOTO stands for Lockout/Tagout, a safety procedure used to ensure that dangerous machines are properly shut off and not started up again prior to the completion of maintenance or servicing work.

• LOTO involves locking the energy isolating devices with an assigned individual lock and tag to prevent the machine from being turned on.

• Types of LOTO include electrical LOTO, mechanical LOTO, and pneumatic LOTO.

• Examples of LOTO devices include padlocks, lockout hasps, circuit breaker l...read more

Transformer parts include core, windings, insulation, and cooling system.

• The core is made of laminated iron or steel and provides a path for magnetic flux.

• Windings consist of primary and secondary coils, which are insulated copper wires.

• Insulation materials like paper, varnish, or oil are used to insulate the windings.

• Cooling systems such as fans, radiators, or oil pumps are used to dissipate heat.

• Other parts include bushings, tap changers, and protective devices.

EHV power transformers consist of several components including windings, core, insulation, bushings, and cooling system.

• Windings - primary and secondary windings made of copper or aluminum

• Core - made of laminated steel to reduce eddy current losses

• Insulation - used to insulate the windings and core from each other

• Bushings - used to connect the transformer to the power system

• Cooling system - used to dissipate heat generated during operation

• Tap changer - used to change the volt...read more

The question is about types of sensors, motors, dol starter, and star delta working.

• Types of sensors include temperature, pressure, proximity, and motion sensors.

• Types of motors include AC motors, DC motors, stepper motors, and servo motors.

• DOL starter is a direct online starter used to start and stop motors.

• Star delta starter is used to reduce the starting current of a motor.

• Star delta working involves starting a motor in star connection and then switching to delta connectio...read more

Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points.

• Ohm's law is represented by the equation I = V/R, where I is the current, V is the voltage, and R is the resistance.

• It is used to calculate the current flowing through a circuit given the voltage and resistance.

• It can also be used to calculate the resistance of a circuit given the voltage and current.

• Ohm's law only applies to conductors that h...read more

A megger is used to measure the insulation resistance of electrical equipment and wiring.

• It helps to detect any insulation breakdown or leakage in electrical systems.

• It is commonly used in the maintenance and testing of transformers, motors, generators, and cables.

• The megger applies a high voltage to the equipment being tested and measures the resistance of the insulation.

• The readings obtained from the megger can help to identify potential problems before they cause equipment...read more

MPCB stands for Motor Protection Circuit Breaker. It is an electrical device used to protect motors from overloads and short circuits.

• MPCB is designed to automatically disconnect the motor from the power supply in case of an overload or short circuit.

• It helps in preventing damage to the motor and other connected equipment.

• MPCB provides protection against thermal overloads, phase failures, and phase unbalance.

• It is commonly used in industrial applications where motors are used...read more

Yes, I am able to read and interpret electrical machine drawings.

• I have experience in reading and interpreting electrical machine drawings

• I am familiar with symbols and notations used in electrical machine drawings

• I can identify different components and their connections in the drawing

• I can use the drawing to troubleshoot and repair electrical machines

• I am proficient in using software tools like AutoCAD and SolidWorks to create and modify electrical machine drawings

A step-up transformer is used to increase the voltage in an electrical circuit.

• Step-up transformers have more turns in the secondary coil than in the primary coil.

• They work based on the principle of electromagnetic induction.

• The primary coil is connected to a power source with a lower voltage, while the secondary coil is connected to the load.

• The increased voltage in the secondary coil is proportional to the ratio of the number of turns in the secondary coil to the number of ...read more

There are various types of electrical motors and transformers, each with their own unique wiring diagrams.

• Types of electrical motors include AC motors, DC motors, stepper motors, and servo motors.

• Transformers can be step-up, step-down, isolation, autotransformers, etc.

• Wiring diagrams vary depending on the specific motor or transformer being used.

• AC motors typically have a capacitor and a start winding in their wiring diagram.

• DC motors have a commutator and brushes in their wi...read more

A transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction.

• Transformers are used to increase or decrease the voltage in an electrical circuit.

• They consist of two or more coils of wire, known as windings, that are wound around a core made of magnetic material.

• The primary winding is connected to the input voltage source, while the secondary winding is connected to the load.

• The ratio of the number of turn...read more

A convertor is an electronic device that converts one form of electrical energy to another.

• Converts AC to DC or vice versa

• Used in power electronics

• Examples include rectifiers, inverters, and DC-DC converters

The power factor for DC is always 1.

• Power factor is the ratio of real power to apparent power in an electrical circuit.

• In DC circuits, the power factor is always 1 because there is no reactive power.

• Reactive power is associated with AC circuits and is caused by inductance and capacitance.

• Since DC circuits do not have inductors or capacitors, there is no reactive power and the power factor is unity.

The type of earthing used in the substation is usually the neutral earthing.

• Neutral earthing is the most common type of earthing used in substations.

• It involves connecting the neutral point of the transformer to the earth.

• This helps to protect the equipment and personnel from electrical faults.

• Other types of earthing include solid earthing, resistance earthing, and reactance earthing.

Current is the flow of electric charge, transformer is a device that transfers electrical energy between two or more circuits, electricity is the flow of electrons, and voltage is the potential difference between two points.

• Current is the flow of electric charge in a circuit, measured in Amperes (A).

• A transformer is a device that transfers electrical energy between two or more circuits through electromagnetic induction.

• Electricity is the flow of electrons through a conductor,...read more

Generator analysis involves examining the voltage and current waveforms to determine phase relationships and power output.

• Generator analysis involves studying the voltage and current waveforms to determine power output

• Phase relationships between voltage and current waveforms are important in generator analysis

• Calculating power output requires understanding the voltage and current values at different points in the waveform

Advantages of synchronous motor include high efficiency, power factor correction, and constant speed.

• High efficiency: Synchronous motors operate at a higher efficiency compared to induction motors, making them ideal for applications where energy savings are important.

• Power factor correction: Synchronous motors help improve the power factor of the system, leading to reduced electricity costs and better utilization of electrical power.

• Constant speed: Synchronous motors maintain...read more

The rating of equipment in a substation is crucial for its efficient functioning.

• The rating of transformers should be based on the maximum load they are expected to carry.

• Circuit breakers should be rated for the maximum fault current they may encounter.

• Busbars should be rated for the maximum current they may carry.

• Lightning arresters should be rated for the maximum voltage they may encounter.

• The rating of capacitors should be based on the reactive power requirement of the sys...read more

Explosion vent in transformer is used for safety purposes.

• It helps to release pressure build-up inside the transformer due to internal faults or external factors.

• It prevents the transformer from exploding and causing damage to the surrounding area.

• The vent is designed to open at a specific pressure level to ensure safe release of gases.

• It is a mandatory safety feature in transformers as per industry standards.

• Examples of external factors that can cause pressure build-up inclu...read more

Cable glands are used to secure and seal cables in various applications based on the area of installation.

• Cable glands are used in hazardous areas to prevent the entry of flammable gases and liquids.

• In outdoor applications, cable glands are used to protect cables from moisture and dust.

• In industrial settings, cable glands are used to secure cables and prevent them from being pulled out.

• Different types of cable glands are used for different types of cables, such as armored or ...read more

HT motor rating is the maximum power it can handle and FLC is the current it draws at full load.

• HT motor rating is expressed in kilowatts (kW) or megawatts (MW).

• FLC of HT motor is the full load current it draws at rated voltage and frequency.

• FLC is expressed in amperes (A) and varies depending on the motor's power rating and efficiency.

• For example, a 1 MW HT motor may have a FLC of 1000 A at 11 kV.

• The rating and FLC of HT motor are important for selecting the appropriate prot...read more

A relay is an electrically operated switch that opens or closes circuits. PLC and SCADA are control systems used in industrial automation.

• Relay is used to control high voltage or current with low voltage or current.

• PLC (Programmable Logic Controller) is a digital computer used for automation of electromechanical processes.

• SCADA (Supervisory Control and Data Acquisition) is a system used for remote monitoring and control of industrial processes.

• PLC and SCADA are used in indust...read more

Cables used in oil and gas are designed to withstand harsh environments and extreme temperatures.

• Oil and gas cables are typically made of materials such as polyethylene, polyurethane, or neoprene.

• They are often armored with steel or aluminum to protect against physical damage.

• Cables used in offshore drilling operations must be able to withstand saltwater corrosion.

• Fiber optic cables are also used in oil and gas for communication and data transmission.

• Examples of oil and gas c...read more