100+ Electrical Supervisor Interview Questions and Answers

LRS maintenance and troubleshooting involves the regular upkeep and identification of issues in electrical systems.

• LRS stands for Low Resistance System, which is used to control and protect electrical equipment.

• Maintenance of LRS includes regular inspections, cleaning, and testing of components to ensure proper functioning.

• Troubleshooting involves identifying and resolving issues such as faulty connections, damaged components, or electrical malfunctions.

• Examples of troublesho...read more

Yes, 10 kW is equal to 13.41 HP.

• 1 kW = 1.34 HP

• Therefore, 10 kW = 10 x 1.34 = 13.41 HP

• Conversion formula: HP = kW x 1.34

Risk assessment involves identifying hazards, evaluating risks, and implementing control measures to mitigate those risks.

• Identify potential hazards in the workplace

• Evaluate the likelihood and severity of each hazard

• Implement control measures to reduce or eliminate risks

• Regularly review and update the risk assessment

• Examples: conducting a job hazard analysis, using safety data sheets to identify chemical hazards

HT cables are high tension cables used for transmitting electricity at high voltages.

• HT cables are designed to carry high voltage electricity, typically above 11kV.

• They are insulated to prevent leakage of current and ensure safety.

• HT cables are usually made of materials like cross-linked polyethylene (XLPE) or ethylene propylene rubber (EPR).

• They are often armored to protect against physical damage and environmental factors.

• HT cables must meet specific standards and regulatio...read more

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

• Transformers are used to increase or decrease the voltage of an alternating current (AC) power supply.

• Safety precautions include proper grounding, insulation, and regular maintenance.

• Transformer oil should be checked regularly for signs of degradation or contamination.

• High voltage warning signs should be posted near transformers.

• Only qualified p...read more

The unit of capacitance is Farad (F)

• The unit of capacitance is named after Michael Faraday

• 1 Farad is equal to 1 Coulomb per Volt

• Common multiples of Farad include microfarad (uF) and picofarad (pF)

Tests for transformers include turns ratio test, insulation resistance test, power factor test, and winding resistance test.

• Turns ratio test measures the turns ratio between primary and secondary windings.

• Insulation resistance test checks the insulation resistance of the transformer windings.

• Power factor test evaluates the power factor of the transformer.

• Winding resistance test measures the resistance of the transformer windings.

Lightning arresters are used to protect electrical equipment from lightning strikes by diverting the high voltage surge to the ground.

• Used in electrical systems to protect equipment from lightning strikes

• Diverts high voltage surges to the ground

• Helps prevent damage to electrical equipment

• Commonly used in power distribution systems, telecommunication networks, and buildings

To overhaul an Electric Induction Motor, you need to disassemble the motor, inspect all components, replace worn out parts, reassemble the motor, and test it for proper functioning.

• Disassemble the motor carefully, noting the position of each component

• Inspect all components for wear and tear, such as bearings, windings, and rotor

• Replace any worn out parts with new ones

• Reassemble the motor following the manufacturer's guidelines

• Test the motor for proper functioning before putti...read more

LT stands for Low Tension and HT stands for High Tension. Safety is the state of being protected from harm. Team management is the process of organizing and coordinating a group of individuals to achieve a common goal.

• LT refers to electrical systems with voltage levels below 1000V while HT refers to systems with voltage levels above 1000V

• Safety involves identifying and mitigating potential hazards in the workplace to prevent accidents and injuries

• Team management involves assi...read more

Yes, there are various testing kits available for electrical connections.

• Multimeter for measuring voltage, current, and resistance

• Insulation resistance tester for checking insulation integrity

• Continuity tester for verifying electrical continuity

• Phase sequence tester for determining correct phase sequence

• Earth resistance tester for measuring earth resistance

I will check the motor's wiring and connections to ensure it is correctly wired for anti-clockwise rotation.

• Check the motor's wiring diagram to confirm the correct connections for anti-clockwise rotation

• Verify the phase sequence of the power supply

• If necessary, swap any two of the three-phase wires to change the rotation direction

• Ensure that the motor is not mechanically jammed or obstructed

The RPM of a 4 pole motor is determined by the frequency of the power supply and the number of poles.

• The RPM of a 4 pole motor is directly proportional to the frequency of the power supply.

• The RPM of a 4 pole motor is inversely proportional to the number of poles.

• For example, a 4 pole motor connected to a 60 Hz power supply will have an RPM of approximately 1800.

• If the power supply frequency is increased to 120 Hz, the RPM of the motor will double to approximately 3600.

UPM in data centre involves managing electrical systems, ensuring uptime, and implementing energy efficiency measures.

• Managing electrical systems to ensure continuous power supply

• Implementing energy efficiency measures to reduce costs

• Monitoring and maintaining backup power systems

• Troubleshooting electrical issues to minimize downtime

• Coordinating with other departments for electrical maintenance schedules

The function of a battery in a dug is to provide electrical power for various equipment and systems.

• The battery supplies electrical energy to power the dug's electrical systems.

• It serves as a backup power source in case of a power outage.

• The battery can be used to start the dug's engine.

• It powers essential equipment such as lights, communication devices, and control systems.

• The battery may also be used to store energy from renewable sources, such as solar panels, for later us...read more

The process charge of a transformer refers to the amount of electrical energy required to magnetize the core and establish the magnetic field.

• The process charge is necessary to create the magnetic flux in the core of the transformer.

• It is typically measured in kilovolt-amperes (kVA) or kilowatts (kW).

• The process charge is essential for the transformer to function properly and efficiently.

• Examples: A 100 kVA transformer may have a process charge of 5 kW.

APFC panel is used to improve power factor and reduce energy consumption.

• APFC panel helps in maintaining a high power factor which reduces energy consumption and saves money.

• It also helps in reducing voltage drops and improves the efficiency of electrical equipment.

• APFC panel is especially useful in industries where there are a lot of inductive loads such as motors and transformers.

• It monitors the power factor and automatically switches capacitors on or off to maintain a high...read more

The unit of power is the watt (W).

• The unit of power is the watt (W)

• Power is the rate at which work is done or energy is transferred

• 1 watt is equal to 1 joule per second

• Common examples of power units include kilowatts (kW) and horsepower (hp)

AC current changes direction periodically while DC current flows in one direction only.

• AC current is used in household appliances while DC current is used in batteries and electronic devices.

• AC current can be easily transformed into different voltages using a transformer while DC current cannot.

• AC current is more dangerous to humans than DC current because it can cause muscle contractions.

• DC current is more efficient for long-distance power transmission because it experiences...read more

A harness is a collection of wires or cables bound together to transmit signals or electrical power. Common defects include fraying, corrosion, and loose connections.

• A harness is used to organize and protect wires or cables in electrical systems.

• Defects in a harness can include fraying of wires, corrosion of connectors, and loose connections.

• Regular inspection and maintenance of harnesses are important to prevent electrical failures.

• Examples of harness defects include exposed...read more

Yes, I received the Employee of the Month award for exceptional performance in improving safety protocols.

• Received Employee of the Month award for improving safety protocols

• Recognized for exceptional performance in maintaining electrical systems

• Appreciated for leadership skills in guiding team to successful project completion

VFD stands for Variable Frequency Drive. It is used to control the speed of an electric motor.

• VFD is used to save energy and reduce wear and tear on motors.

• It can be used in HVAC systems, pumps, and fans.

• VFD works by adjusting the frequency of the electrical supply to the motor.

• It allows for precise control of motor speed and can also provide soft starting and stopping.

• VFD can also monitor and protect the motor from overload and overvoltage.

Star-Delta starter is used to start 3-phase motors. It reduces the starting current and torque.

• Star-Delta starter connects the motor in star configuration during starting to reduce the starting current and torque.

• After a few seconds, the starter switches the motor to delta configuration for normal operation.

• This method is used for motors with high starting current and torque requirements.

• It is commonly used in industries for heavy-duty machines like compressors, pumps, and co...read more

Construction building in raising panel installation involves proper planning, coordination, and adherence to safety regulations.

• Ensure all necessary materials and equipment are available before starting the installation process

• Coordinate with other trades to ensure smooth workflow and avoid conflicts

• Follow safety regulations and guidelines to prevent accidents and injuries

• Properly train and supervise workers to ensure quality workmanship

• Regularly inspect and maintain the inst...read more

There are two types of substations - indoor and outdoor substations.

• Indoor substations are located inside buildings or structures.

• Outdoor substations are located outside and are exposed to the elements.

• Indoor substations are typically smaller and require less maintenance.

• Outdoor substations are larger and require more maintenance due to exposure to weather conditions.

• Both types of substations play a crucial role in the distribution of electrical power.

DC motors are electric motors that operate using direct current (DC) power sources.

• DC motors convert electrical energy into mechanical energy through the interaction of magnetic fields.

• They are commonly used in appliances, power tools, and electric vehicles.

• DC motors have two main types: brushed DC motors and brushless DC motors.

• Brushed DC motors use brushes to conduct current, while brushless DC motors use electronic controllers.

• DC motors can vary in size and power output de...read more

DOL starter is a direct-on-line starter used to start 3-phase motors by connecting them directly to the power supply.

• DOL starter provides full voltage to the motor at the start

• It consists of a contactor, overload relay, and start/stop push buttons

• The contactor connects the motor to the power supply

• The overload relay protects the motor from overloading

• The start/stop push buttons control the on/off function of the motor

Erection of GIS and overhead line involves careful planning, coordination, and execution to ensure safety and efficiency.

• Ensure proper site preparation and foundation for GIS equipment installation

• Coordinate with design team for accurate placement of GIS components

• Follow manufacturer's guidelines for assembly and installation of GIS equipment

• Inspect and test GIS components for proper functioning before energizing

• For overhead line, plan route, procure materials, and install su...read more

Transformer erection involves proper planning, preparation, and execution to ensure safe and efficient installation.

• Ensure proper site preparation and foundation for the transformer

• Coordinate with crane operators for lifting and placing the transformer

• Connect electrical cables and perform insulation testing

• Verify proper grounding and connections for safety

• Commission the transformer and conduct performance tests

HT&LT motors and breakers are operated and maintained differently due to their voltage levels.

• HT motors are high voltage motors typically above 1000V, while LT motors are low voltage motors below 1000V.

• HT motors require specialized equipment and training for operation and maintenance.

• Breakers for HT motors are designed to handle high voltages and currents, while LT breakers are for lower voltages.

• Regular maintenance and testing are crucial for both HT and LT motors and breake...read more

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

• Transformers have two coils of wire, known as primary and secondary coils.

• When an alternating current flows through the primary coil, it creates a changing magnetic field.

• This changing magnetic field induces a voltage in the secondary coil, transferring electrical energy.

• The ratio of turns in the primary and secondary coils determines the voltage transfor...read more

Power system is a network of electrical components used to generate, transmit, and distribute electrical power.

• Power system is a network of power generation plants, transmission lines, substations, and distribution networks.

• It involves the generation of electrical power from various sources such as coal, natural gas, hydro, wind, or solar.

• The generated power is then transmitted over long distances through high-voltage transmission lines.

• At substations, the voltage is stepped ...read more

Major hazards in HV lines include electric shock, arc flash, and equipment failure.

• Electric shock from direct contact with live wires

• Arc flash incidents due to high voltage levels

• Equipment failure leading to power outages or fires

A dropout switch is an electrical switch that opens when the voltage drops below a certain level.

• It is used to protect electrical equipment from damage due to low voltage.

• It can be manually or automatically reset.

• Examples include low voltage disconnect switches and thermal overload switches.

• It is commonly used in battery systems to prevent over-discharge.

• It is also used in power distribution systems to prevent damage to transformers and other equipment.

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

• Transformers are used to increase or decrease the voltage of an alternating current (AC) power supply.

• They consist of two coils of wire, called the primary and secondary coils, wrapped around a magnetic core.

• When an AC voltage is applied to the primary coil, it creates a magnetic field that induces a voltage in the secondary coil.

• Transformers ar...read more

We are currently using Siemens S7-1200 PLC in our organisation.

• Siemens S7-1200 PLC is being used for automation and control processes

• It offers high performance and reliability for industrial applications

• The programming software used is TIA Portal for programming and monitoring PLC operations

The unit of Energy is Joule (J)

• The unit of Energy is Joule (J)

• Energy can also be measured in kilowatt-hours (kWh)

• 1 Joule is equal to 1 watt-second

Transformer OLTC maintenance involves regular inspection, cleaning, lubrication, and testing of the on-load tap changer.

• Inspect the OLTC for any signs of damage or wear

• Clean the contacts and mechanism to ensure proper functioning

• Lubricate moving parts to reduce friction and prevent corrosion

• Perform electrical testing to verify the OLTC's performance

• Document maintenance activities and keep records for future reference

VCB and SF6 are both types of circuit breakers used in electrical systems.

• VCB stands for Vacuum Circuit Breaker, while SF6 stands for Sulfur Hexafluoride Circuit Breaker.

• VCBs use vacuum interrupters to extinguish the arc when the circuit is broken, while SF6 circuit breakers use sulfur hexafluoride gas.

• VCBs are typically used for medium voltage applications, while SF6 circuit breakers are commonly used for high voltage applications.

• SF6 circuit breakers have higher insulation ...read more

A control system is a system that manages, commands, directs, or regulates the behavior of other devices or systems.

• Control systems are used to maintain desired outputs in various processes.

• They can be implemented using hardware, software, or a combination of both.

• Examples include thermostat control in HVAC systems, cruise control in vehicles, and automatic voltage regulators in power systems.

A permit system is a set of procedures and documents required to ensure safety and compliance with regulations before starting a job.

• Permit systems are used to control hazardous work activities.

• They involve obtaining permits and following specific procedures before starting work.

• Examples include hot work permits, confined space permits, and excavation permits.

• Permit systems help prevent accidents and ensure compliance with regulations.

• They are typically used in industries suc...read more

Isolation transformers are used to isolate electrical devices from the power source for safety and protection.

• Isolation transformers have primary and secondary windings that are electrically separated to prevent direct current flow between the input and output.

• They are commonly used in medical equipment, data centers, and sensitive electronic devices to protect them from electrical noise and voltage spikes.

• Isolation transformers can also be used to step up or step down voltag...read more

Transformers are electrical devices that transfer energy between two or more circuits through electromagnetic induction, ensuring safety and efficiency.

• Types of transformers include step-up, step-down, isolation, and auto-transformers.

• Safety measures for transformers include proper grounding, regular maintenance, and overcurrent protection.

• Friction in transformers can lead to overheating and insulation breakdown, so proper lubrication and cooling systems are essential.

• Example...read more

Star delta starter is used to reduce starting current in induction motors by initially connecting the motor windings in a star configuration and then switching to a delta configuration.

• Star delta starter is commonly used in applications where high starting current is a concern, such as large induction motors.

• It involves connecting the motor windings in a star configuration during starting to reduce the current drawn from the power supply.

• Once the motor reaches a certain speed...read more

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

• The unit of current is Ampere (A)

• Current is the rate of flow of electric charge

• Commonly represented by the symbol 'I'

• 1 Ampere is equivalent to 1 Coulomb per second

A DC machine is an electrical machine that converts direct current electrical power into mechanical power.

• Types of DC machines include DC generators and DC motors

• DC generators convert mechanical power into direct current electrical power

• DC motors convert direct current electrical power into mechanical power

• Examples of DC machines include permanent magnet DC motors and series wound DC motors

Mineral oil is commonly used in transformers for insulation and cooling purposes.

• Mineral oil is the most commonly used oil in transformers due to its high dielectric strength and thermal conductivity.

• It helps in insulating the transformer windings and dissipating heat generated during operation.

• Other types of oils used in transformers include silicone oil and synthetic esters.

• The choice of oil depends on factors such as cost, environmental impact, and fire safety regulations.