50+ Senior Electrical Technician Interview Questions and Answers

The appropriate fire extinguisher to use in an electrical fire is a Class C fire extinguisher.

• Class C fire extinguishers are specifically designed to extinguish fires involving electrical equipment.

• They contain non-conductive extinguishing agents, such as carbon dioxide or dry chemical powder, to safely put out the fire without conducting electricity.

• It is important to never use water or foam-based extinguishers on electrical fires as they can conduct electricity and potentia...read more

The hydraulic pump is responsible for generating the flow of hydraulic fluid in a hydraulic circuit.

• The hydraulic pump converts mechanical energy into hydraulic energy.

• It creates the pressure needed to move the hydraulic fluid through the circuit.

• The pump provides the force necessary to operate hydraulic actuators, such as cylinders or motors.

• It ensures the proper functioning of the hydraulic system by maintaining a consistent flow of fluid.

• Examples of hydraulic pumps include...read more

The battery voltage decreases during discharge.

• Battery voltage decreases as the battery discharges.

• The rate of voltage decrease depends on the battery's capacity and load.

• For example, a fully charged 12V battery may drop to 11V after discharging for a certain period.

• Battery voltage can be measured using a voltmeter.

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

• Generators are commonly used to provide backup power during electrical outages.

• They work on the principle of electromagnetic induction.

• Generators can be powered by various sources such as gasoline, diesel, natural gas, or renewable energy.

• They are used in various applications including residential, commercial, and industrial sectors.

• Examples of generators include portable generators, standby genera...read more

In a power failure situation, it is important to have a plan in place to manage the situation effectively.

• Ensure backup power sources are available, such as generators or uninterruptible power supplies (UPS)

• Implement a power outage response plan that includes procedures for safely shutting down equipment and systems

• Regularly test backup power systems to ensure they are in working order

• Have emergency lighting and communication systems in place

• Train staff on power failure proto...read more

To manage overloads, ensure proper circuit design, use protective devices, monitor load levels, and implement load shedding.

• Design circuits with appropriate capacity to handle expected loads.

• Install protective devices like circuit breakers and fuses to prevent overloads.

• Regularly monitor load levels using ammeters or power monitoring systems.

• Implement load shedding techniques to prioritize critical loads during high demand.

• Consider using power factor correction techniques to ...read more

To connect a battery in a UPS, follow these steps:

• Identify the positive and negative terminals of the battery

• Connect the positive terminal of the battery to the positive terminal of the UPS

• Connect the negative terminal of the battery to the negative terminal of the UPS

• Ensure the connections are secure and tight

• Verify the battery voltage and capacity compatibility with the UPS

• Consider using appropriate cables and connectors for the connection

I am responsible for carrying out condition monitoring, maintenance, and troubleshooting of electrical equipment.

• Perform scheduled condition monitoring, LLF, and thermography

• Conduct preventive, predictive, and breakdown maintenance of electrical equipment

• Possess good knowledge of troubleshooting electrical circuits

• Adept at reading and modifying control schematic diagrams

• Ensure smooth operations of electrical equipment

The earth ohm resistance refers to the resistance of the earth or ground in an electrical circuit.

• Earth ohm resistance is a measure of how easily current can flow through the earth.

• It is important to have a low earth ohm resistance to ensure proper grounding and safety in electrical systems.

• The earth ohm resistance can vary depending on factors such as soil composition, moisture content, and temperature.

• Typically, a good earth ohm resistance value is below 5 ohms.

• Earth ohm re...read more

A capacitor stores electrical energy and releases it when needed.

• Capacitors are used to filter out noise and stabilize voltage in power supplies.

• They are also used in timing circuits, oscillators, and filters.

• Capacitors can be polarized or non-polarized, and have different capacitance values.

• They are commonly found in electronic devices such as TVs, radios, and computers.

A rectifier is an electrical device that converts alternating current (AC) to direct current (DC).

• Rectifiers are commonly used in power supplies to convert AC voltage to DC voltage.

• They are made up of diodes, which allow current to flow in only one direction.

• Rectifiers can be half-wave or full-wave, depending on the number of diodes used.

• Examples of rectifiers include bridge rectifiers, vacuum tube rectifiers, and solid-state rectifiers.

Electrical current unit is measured in Amperes (A).

• Electrical current unit is the measure of the flow of electric charge.

• It is measured in Amperes (A) and is named after the French physicist Andre-Marie Ampere.

• One Ampere is defined as the amount of current that flows when one Coulomb of charge passes through a conductor in one second.

• Electrical current is the rate at which electric charge flows through a circuit.

• It is an essential concept in electrical engineering and is used...read more

A digital multimeter (DMM) is commonly used for earth testing.

• A digital multimeter (DMM) is a versatile tool that can measure resistance, voltage, and current.

• For earth testing, the DMM is used to measure the resistance between the earth electrode and the grounding system.

• The DMM should be set to the resistance (ohms) mode and connected to the earth electrode and grounding system.

• The measured resistance value helps determine the effectiveness of the grounding system.

• Other spe...read more

The cable required for a 30 KW load depends on the voltage and current rating.

• The cable size is determined by the current carrying capacity and voltage drop requirements.

• The current carrying capacity of a cable depends on its cross-sectional area.

• The voltage drop should be within acceptable limits to ensure proper functioning of the load.

• Factors like cable material, installation method, and ambient temperature also affect cable selection.

• Consulting relevant standards and guid...read more

AHU stands for Air Handling Unit. It is used in HVAC systems to regulate and circulate air in buildings.

• AHU stands for Air Handling Unit.

• It is a device used in HVAC (Heating, Ventilation, and Air Conditioning) systems.

• AHUs are responsible for regulating and circulating air in buildings.

• They help maintain indoor air quality and temperature.

• AHUs are commonly found in commercial buildings, hospitals, schools, and industrial facilities.

• They can be used in both new construction an...read more

There are two types of motors: AC motors and DC motors.

• AC motors are powered by alternating current and are commonly used in household appliances and industrial machinery.

• DC motors are powered by direct current and are often found in battery-operated devices and electric vehicles.

A CT is a Current Transformer used to measure the flow of current.

• CT stands for Current Transformer.

• It is a device used to step down high currents to a safe level for measurement or protection purposes.

• CTs are commonly used in electrical power systems to monitor and control current flow.

• They consist of a primary winding and a secondary winding, where the primary winding is connected in series with the current being measured.

• The secondary winding produces a proportional curren...read more

SF⁶ breaker is a type of circuit breaker that uses sulfur hexafluoride gas as the medium for extinguishing the arc.

• SF⁶ breaker is commonly used in high-voltage electrical systems.

• It is known for its excellent insulating properties and high dielectric strength.

• The sulfur hexafluoride gas in the breaker acts as an effective cooling and arc-quenching medium.

• SF⁶ breaker is often used in power transmission and distribution systems, as well as in industrial settings.

• It is designed ...read more

There are various types of transformers such as power transformers, distribution transformers, autotransformers, isolation transformers, etc.

• Power transformers are used in high voltage transmission systems.

• Distribution transformers are used to step down the voltage for distribution to homes and businesses.

• Autotransformers have a single winding and are used for voltage regulation.

• Isolation transformers are used to isolate a circuit from the power source.

• Other types include ins...read more

Yes, I have experience in maintaining HT motors and troubleshooting issues.

• Yes, I have experience in maintaining HT motors and troubleshooting any issues that may arise.

• I am familiar with conducting regular maintenance checks on HT motors to ensure they are functioning properly.

• I have the skills to diagnose and repair any problems that may occur with HT motors, such as overheating or electrical issues.

HT capacitor nct working principle involves storing electrical energy in an electric field.

• HT capacitors store electrical energy in an electric field

• They are used in high voltage applications to improve power factor and reduce reactive power

• The working principle involves charging and discharging of the capacitor to regulate voltage levels

There are two types of electricity: static electricity and dynamic electricity.

• Static electricity is the buildup of electric charge on an object without any flow of electric current.

• Dynamic electricity is the flow of electric charge through a conductor.

• Examples of static electricity include rubbing a balloon on hair and getting shocked by touching a doorknob.

• Examples of dynamic electricity include the electricity flowing through wires in our homes and powering electronic devi...read more

The voltage in HT lines can vary depending on the application, but common voltages include 11kV, 25kV, 33kV, 66kV, 132kV, 220kV, 400kV, and 500kV.

• HT lines typically carry higher voltages than low-tension lines.

• The voltage in HT lines is used for transmitting electricity over long distances.

• Higher voltage levels in HT lines reduce power losses during transmission.

• Examples of HT lines include transmission lines for power plants and substations.

Earthing is necessary in switchyards to protect equipment and personnel from electrical hazards.

• Earthing provides a low resistance path for fault currents to flow, preventing damage to equipment and reducing the risk of electrical shock to personnel.

• It helps to maintain the potential of the equipment at zero volts, preventing the buildup of static electricity.

• Earthing also helps to reduce electromagnetic interference (EMI) and radio frequency interference (RFI) in the switchy...read more

Regular maintenance of motors, transformers, VSDs, and panels is crucial for their optimal performance and longevity.

• Inspect and clean motors and transformers regularly to prevent dust buildup and overheating

• Check VSDs for any signs of wear and tear, and replace faulty components as needed

• Perform routine inspections of panels to ensure proper wiring and connections

• Keep a record of maintenance activities and schedule regular maintenance intervals

• Train personnel on proper maint...read more

Types of circuit breakers include thermal, magnetic, and hybrid. They are used in residential, commercial, and industrial settings.

• Thermal circuit breakers are commonly used in residential applications to protect against overcurrents.

• Magnetic circuit breakers are often used in industrial settings to protect against short circuits.

• Hybrid circuit breakers combine the features of thermal and magnetic breakers for enhanced protection.

• Circuit breakers are used in electrical panels...read more

An electrical starter is a device used to start an electrical motor by providing the initial power to overcome inertia.

• Electrical starters are commonly used in various industrial applications to start motors

• They can be manual or automatic

• Examples include direct-on-line starters, star-delta starters, and soft starters

Conveyor belts require proper safety measures and protection devices to prevent accidents.

• Safety measures include emergency stop buttons, guards, and warning signs.

• Protection devices include sensors to detect jams or blockages, and automatic shut-off systems.

• Regular maintenance and inspections are necessary to ensure safety and prevent malfunctions.

• Training for employees on proper use and safety procedures is also important.

• Examples of protection devices include pull cord swi...read more

The last rating MCB can go up to 125 amps.

• The last rating MCB can typically go up to 125 amps.

• MCBs are available in various ratings such as 6A, 10A, 16A, 32A, 63A, and 125A.

• The rating of an MCB determines the maximum current it can safely handle before tripping.

• For higher current requirements, larger MCBs or other protective devices like MCCBs may be used.

Switchyard is a substation that connects power from generators to the grid. Switchgear is the equipment used to control and protect the switchyard.

• Switchyard is a part of an electrical power system that connects generators to the grid

• It is a substation that contains transformers, circuit breakers, and other equipment

• Switchgear is the equipment used to control and protect the switchyard

• It includes devices such as circuit breakers, relays, and disconnect switches

• Switchgear is u...read more

A tap changer is used in transformers to adjust the number of turns in the winding and regulate the voltage output.

• Allows for voltage regulation in transformers

• Helps to adjust the number of turns in the winding

• Ensures a consistent voltage output despite fluctuations in input voltage

• Commonly used in power distribution systems and electrical substations

DOL starter directly connects the motor to the power supply, while star delta starter initially starts the motor in star configuration before switching to delta configuration.

• DOL starter provides full voltage to the motor from the start, causing high starting current and torque

• Star delta starter reduces the starting current and torque by initially connecting the motor in star configuration

• DOL starter is simpler and cheaper compared to star delta starter

• Star delta starter is u...read more

Transformer high voltage test is conducted to ensure the insulation system can withstand the rated voltage without breakdown.

• Ensure the transformer is properly grounded before conducting the test.

• Apply the high voltage to the transformer windings and measure the insulation resistance.

• Monitor for any signs of breakdown such as sparking or abnormal noises.

• Perform the test at different voltage levels to ensure the insulation can withstand the rated voltage.

• Record the test result...read more

A Dol Control wiring diagram drawing is a schematic representation of the wiring connections for a Direct-On-Line motor control system.

• DOL Control wiring diagrams typically show the connections between the motor, contactor, overload relay, and power supply.

• The diagram may include symbols for components such as motor starters, fuses, switches, and terminals.

• It is important to follow the wiring diagram accurately to ensure proper functioning of the motor control system.

The Indian standard frequency is 50 Hz.

• The Indian standard frequency is used for power supply in India.

• It is also known as the mains frequency.

• It is different from the frequency used in some other countries like the US (60 Hz).

CT and PT are electrical devices used in power systems to measure current and voltage respectively.

• CT stands for Current Transformer and is used to measure high currents by stepping down the current to a lower value.

• PT stands for Potential Transformer and is used to measure high voltages by stepping down the voltage to a lower value.

• CTs and PTs are commonly used in power distribution systems to provide accurate measurements for protection and control purposes.

Zebra conductor is a type of cable used in high-voltage power transmission.

• It is a concentric cable with a central core surrounded by layers of conductive and insulating materials.

• The layers are arranged in a striped pattern, giving the cable its name.

• Zebra conductors are used in high-voltage power lines to reduce corona discharge and improve efficiency.

• They are also used in underground power transmission systems.

• Zebra conductors are more expensive than traditional cables but...read more

MCR stands for Maximum Continuous Rating and CRP stands for Control Room Panel.

• MCR is the maximum power output that a generator or motor can sustain continuously without overheating or damaging its components.

• CRP is a control panel that allows operators to monitor and control various electrical systems in a facility or plant.

• MCR and CRP are important concepts in electrical engineering and are commonly used in power generation and distribution systems.

• For example, a power plan...read more

I handle site by ensuring safety, efficiency, and communication.

• I prioritize safety measures and ensure all equipment is up to code.

• I strive for efficiency in all tasks and work to minimize downtime.

• I maintain open communication with team members and management to address any issues or concerns.

• I regularly inspect and maintain equipment to prevent breakdowns and ensure optimal performance.

• I keep detailed records and documentation of all work performed on site.

Unequal 3-phase AC line voltage can cause various issues in electrical systems.

• Unequal voltage can cause unbalanced loads, leading to overheating and damage to equipment.

• It can also cause voltage drops and affect the performance of motors and other devices.

• Proper monitoring and maintenance can help prevent these issues.

• Possible causes of unequal voltage include faulty wiring, damaged transformers, and unbalanced loads.

• Measuring the voltage at different points in the system ca...read more

Possible causes could be faulty motor, broken belt, or tripped overload protection.

• Check if the motor is receiving power and if the starter is functioning properly.

• Inspect the motor for any signs of damage or wear and tear.

• Check the belt for any signs of damage or if it has come off the pulley.

• Check the overload protection to see if it has tripped and needs to be reset.

• If all else fails, consult a professional for further diagnosis and repair.

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 voltage levels in electrical circuits.

• They consist of two coils of wire, known as the primary and secondary coils.

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

• Transformers are commonly used in power distribution systems, electric...read more

Ring main unit is a type of switchgear used in electrical distribution systems to control and protect power cables.

• Ring main unit consists of a ring of interconnected switches and fuses to distribute power to multiple circuits.

• It is used to isolate faulty sections of the network and maintain power supply to the rest of the system.

• Ring main unit can be operated manually or automatically depending on the design.

• Examples of ring main unit manufacturers include ABB, Schneider Ele...read more

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

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

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

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

• Transformers...read more

There are several types of breakers used in electrical systems for different purposes.

• Circuit breakers - used to protect electrical circuits from overloads and short circuits

• Fuse - a type of breaker that contains a metal strip that melts when overloaded

• GFCI (Ground Fault Circuit Interrupter) - used to protect against electric shock in wet areas

• Arc Fault Circuit Interrupter (AFCI) - detects dangerous arcing in electrical circuits

• Miniature Circuit Breaker (MCB) - a type of circ...read more

Control wiring is the wiring used to connect and control electrical devices in a system.

• Control wiring is used to connect various electrical components such as switches, relays, and sensors in a system.

• It is used to transmit signals and commands to control the operation of different devices.

• Control wiring is typically low voltage and carries signals rather than power.

• It is essential for the proper functioning of automated systems and machinery.

• Examples of control wiring inclu...read more

Current is the flow of electric charge, measured in Amperes, while voltage is the force that drives the current, measured in Volts.

• Current is the rate of flow of electric charge in a circuit.

• Voltage is the electrical potential difference that drives the current.

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

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