300+ Electrical Technician Interview Questions and Answers

The color code of resistance is a system used to identify the resistance value and tolerance of resistors.

• The color code consists of bands of different colors that represent specific values and tolerances.

• The first two bands indicate the significant digits of the resistance value.

• The third band represents the multiplier or the number of zeros to be added to the significant digits.

• The fourth band indicates the tolerance of the resistor.

• For example, a resistor with bands of bro...read more

An electrical technician is responsible for installing, maintaining, and repairing electrical systems and equipment.

• Installing electrical systems and equipment

• Maintaining electrical systems and equipment

• Repairing electrical systems and equipment

• Troubleshooting electrical issues

• Reading and interpreting technical diagrams and blueprints

• Ensuring compliance with safety regulations

• Testing electrical systems for functionality

• Collaborating with engineers and other technicians

Possible problems in starter and motor causing motor not to start.

• Check if there is power supply to the starter

• Inspect for any loose connections or damaged wires in the starter circuit

• Examine the starter motor for any mechanical issues such as worn out brushes or bearings

• Verify if the motor itself is faulty by checking for continuity and resistance in windings

The number of transformers depends on the specific context and location.

• The number of transformers can vary depending on the size and purpose of the electrical system.

• In a residential area, there may be one transformer serving multiple houses.

• In a commercial or industrial setting, there may be multiple transformers to meet the power demands.

• Transformers can also be found in power substations, where they step up or step down the voltage for transmission and distribution purpos...read more

Star delta is a method of connecting three-phase motors to reduce starting current and torque.

• It involves connecting the motor windings in a star configuration during starting and then switching to a delta configuration once the motor is up to speed.

• This reduces the voltage applied to each winding during starting, which in turn reduces the current drawn from the power supply.

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

• The star delta method can a...read more

I have worked with various control voltage applications in my previous roles.

• I have experience with control voltage applications in industrial machinery and equipment.

• I am familiar with troubleshooting and repairing control voltage circuits.

• I have worked with PLCs and other control systems that use control voltage.

• Examples of control voltage applications I have worked with include motor starters, relays, and solenoids.

Basic electrical wiring refers to the process of connecting electrical components in a circuit to allow electricity to flow and power devices.

• Basic electrical wiring involves connecting wires to electrical components such as switches, outlets, and light fixtures.

• The wiring must follow specific codes and standards to ensure safety and proper functioning.

• Common types of wiring include single-conductor, multi-conductor, and twisted pair.

• Proper insulation and grounding are essent...read more

To find the circuit during lighting maintenance and reset, follow these steps:

• Start by identifying the circuit breaker or fuse box that controls the lighting circuit.

• Turn off the circuit breaker or remove the fuse to ensure safety.

• Use a voltage tester to confirm that the circuit is not live.

• Inspect the lighting fixtures and wiring for any visible signs of damage or loose connections.

• If necessary, replace any faulty components or repair any damaged wiring.

• Once the maintenance ...read more

To install a servo 3 phase stabilizer, follow these steps: prepare the installation site, mount the stabilizer, connect the input and output terminals, and test the stabilizer.

• Prepare the installation site by ensuring it is clean, dry, and well-ventilated.

• Mount the stabilizer securely to a stable surface using appropriate mounting hardware.

• Connect the input terminals of the stabilizer to the power source, ensuring proper phase and voltage matching.

• Connect the output terminals...read more

Types of transformers include power transformers, distribution transformers, instrument transformers. Types of electrical drives include AC drives, DC drives, servo drives.

• Power transformers are used in high voltage transmission and distribution systems.

• Distribution transformers are used to step down voltage for use in homes and businesses.

• Instrument transformers are used for measuring voltage and current in power systems.

• AC drives control the speed of AC motors.

• DC drives con...read more

UPS is used to provide backup power in case of electrical outages or fluctuations.

• Provides continuous power supply during outages

• Protects sensitive electronic equipment from damage due to power surges or fluctuations

• Allows for safe shutdown of devices to prevent data loss

• Commonly used in data centers, hospitals, and critical infrastructure

• Types include offline, line-interactive, and online UPS

Diode is a semiconductor device that allows current to flow in one direction. Capacitor stores electrical energy. Motor converts electrical energy into mechanical energy. Multimeter measures voltage, current, and resistance.

• Diode is a semiconductor device with two terminals that allows current to flow in one direction only.

• Capacitor is an electronic component that stores electrical energy and releases it when needed.

• Motor is a device that converts electrical energy into mecha...read more

The motor nameplate provides important information about the motor, such as its power rating, voltage, current, and efficiency. The transformer nameplate contains details about the transformer's capacity, voltage ratio, impedance, and cooling method.

• Motor nameplate includes power rating, voltage, current, and efficiency

• Transformer nameplate contains capacity, voltage ratio, impedance, and cooling method

• Motor nameplate example: Power rating - 5 HP, Voltage - 230V, Current - 20...read more

The voltage in three-phase power systems is typically 208 volts, 240 volts, or 480 volts.

• Three-phase power systems are commonly used in industrial and commercial applications.

• The voltage in a three-phase system depends on the specific application and the power requirements.

• Common voltages in three-phase systems include 208 volts, 240 volts, and 480 volts.

• Higher voltage levels are typically used for larger industrial equipment and machinery.

• Lower voltage levels may be used for...read more

There are different types of earthing such as TN, TT, and IT. The voltage of earthing can vary depending on the type of earthing system.

• Types of earthing include TN, TT, and IT

• TN system has a voltage of 230V to earth

• TT system has a voltage of 400V to earth

• IT system has a voltage of 400V to earth

The process for entering single-phase voltage involves connecting the voltage source to the load through a single conductor.

• Connect the single-phase voltage source to the load through a single conductor

• Ensure proper insulation and grounding for safety

• Check the voltage level using a multimeter before connecting the load

• Make sure the load is compatible with the voltage rating

Basic information on wiring and phase natural

• Wiring refers to the system of electrical connections in a building or device

• Phase refers to the distribution of electrical power in alternating current systems

• Natural phase refers to the standard distribution of phases in a power system

• Understanding wiring and phase natural is crucial for safe and efficient electrical installations

• Examples: 3-phase wiring in industrial settings, single-phase wiring in residential buildings

Star delta contactors are used in electrical systems to control the starting and stopping of three-phase motors.

• Star delta contactors are used to reduce the starting current of three-phase motors.

• They are commonly used in industrial applications where large motors are used.

• The contactors switch the motor windings from a star configuration to a delta configuration.

• This reduces the voltage across each winding and limits the inrush current during motor startup.

• Once the motor rea...read more

NGR stands for Neutral Grounding Resistor. It is used in high voltage generation to limit the fault current and protect the equipment.

• NGR limits the fault current by increasing the impedance of the neutral point of the transformer or generator.

• It protects the equipment from damage due to high fault current.

• NGR is commonly used in power plants, substations, and industrial facilities.

• It is also used in arc furnaces and welding machines to limit the current.

• NGR can be either fix...read more

Mecline is kept at a temperature of 25 degrees Celsius in Domino.

• Mecline is stored at a specific temperature in Domino.

• The temperature at which Mecline is kept is 25 degrees Celsius.

• Maintaining the correct temperature is important for the stability and effectiveness of Mecline.

• Temperature control ensures the quality and integrity of Mecline.

• Incorrect storage temperature can affect the potency and shelf life of Mecline.

There are 10 generators in our company.

• Our company has invested in 10 generators for power backup.

• The generators range from 50kVA to 500kVA.

• Regular maintenance and testing is conducted to ensure their proper functioning.

• The generators are strategically placed in different locations to ensure uninterrupted power supply.

The number of windings inside a transformer depends on its design and purpose.

• The primary winding is connected to the input voltage source.

• The secondary winding is connected to the load.

• Transformers can have multiple windings for different voltage levels or phases.

• The number of turns in each winding determines the voltage ratio of the transformer.

• For example, a step-up transformer may have more turns in the secondary winding to increase the voltage.

• The number of windings also...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 electrical power transmission and distribution systems.

• There are two main types of transformers: step-up transformers, which increase voltage, and step-down transformers, which decrease voltage.

• Other types of transformers include autotransformers, isolation transformers, and instrumen...read more

Capacitor is connected across to make the DC supply smooth and filter out any ripples.

• Capacitor filters out any AC component from the DC supply

• Capacitor stores charge and releases it when voltage drops

• Capacitor reduces voltage spikes and noise in the circuit

An electrician is a skilled tradesperson who installs, maintains, and repairs electrical systems and equipment.

• Electricians work with a variety of tools and equipment to install and repair electrical systems in buildings, homes, and other structures.

• They are responsible for reading and interpreting electrical blueprints and diagrams to determine the layout and installation of wiring, circuits, and other electrical components.

• Electricians must adhere to safety protocols and re...read more

Insulators prevent the flow of electric current, while dielectrics can store electric energy.

• Insulators do not allow electric current to pass through them

• Dielectrics can store electric energy when placed in an electric field

• Insulators are used to separate conductors and prevent electrical leakage

• Dielectrics are commonly used in capacitors to store and release electrical energy

Various faults can occur in high-tension (h.t) breakers.

• Short circuit fault

• Overload fault

• Mechanical fault

• Insulation fault

• Arcing fault

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 power source, while the secondary winding is connected to the load.

• The transformer operates based on the p...read more

Tube light diagram shows the components of a fluorescent light fixture. Star delta diagram is used for motor starting. 3 phase voltage is typically 415V, single phase voltage is 230V.

• Tube light diagram includes components like starter, choke, and fluorescent tube.

• Star delta diagram is used for starting induction motors to reduce starting current.

• 3 phase voltage is usually 415V in industrial settings.

• Single phase voltage is commonly 230V in residential areas.

The size of the spanner to use depends on the size of the nut bolt.

• For a 6mm nut bolt, use a 6mm spanner.

• For a 7mm nut bolt, use a 7mm spanner.

• For an 8mm nut bolt, use an 8mm spanner.

• For a 9mm nut bolt, use a 9mm spanner.

• For a 10mm nut bolt, use a 10mm spanner.

The boost pressure sensor measures the pressure of the air entering the engine to ensure optimal performance.

• Measures pressure of air entering engine

• Helps ensure optimal engine performance

• Sends data to engine control unit for adjustments

• Commonly found in turbocharged engines

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

• Transformers work on the principle of electromagnetic induction.

• They consist of two or more coils of wire, known as windings, which 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.

• When an alternating current flows through the pri...read more

To check motor conditions, perform visual inspection, measure voltage and current, check for abnormal noises, and test motor performance.

• Perform a visual inspection to check for any physical damage or loose connections.

• Measure the voltage and current using a multimeter to ensure they are within the specified range.

• Listen for any abnormal noises such as grinding or squealing that may indicate motor issues.

• Test the motor performance by running it under load and checking for any...read more

Priority should be given to safety first, then addressing the product problem.

• Safety of personnel and equipment should always be the top priority

• Once safety is ensured, focus on identifying and resolving the product problem

• Ignoring safety protocols can lead to accidents and further product issues

Stall in a motor refers to a condition where the motor stops rotating despite the presence of power supply.

• Stall occurs when the motor is overloaded or when there is a mechanical obstruction preventing the motor from rotating.

• It can also occur when the motor is underpowered or when there is a fault in the electrical system.

• Stall can cause damage to the motor and other components if not addressed promptly.

• Examples of motors that can experience stall include AC motors, DC motor...read more

A motor is a device that converts electrical energy into mechanical energy. Types include AC motors (induction, synchronous) and DC motors (brushed, brushless).

• A motor is a device that converts electrical energy into mechanical energy

• Types of motors include AC motors (induction, synchronous) and DC motors (brushed, brushless)

• AC motors are commonly used in household appliances and industrial applications

• DC motors are often found in tools, toys, and automotive applications

UPS stands for Uninterruptible Power Supply. It is a device that provides emergency power to a load when the input power source fails.

• UPS has three main parts: battery, inverter, and rectifier.

• The battery stores energy and provides power during outages.

• The rectifier converts AC power to DC power to charge the battery.

• The inverter converts DC power from the battery to AC power for the load.

• UPS ensures continuous power supply to critical equipment like computers, servers, and m...read more

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

• Power factor is a unitless value between 0 and 1.

• It indicates how effectively electrical power is being converted into useful work output.

• A higher power factor signifies more efficient energy usage.

• Power factor can be improved by using power factor correction devices.

• Formula: Power Factor = Real Power / Apparent Power

To repair a short circuit, first identify the source of the short and then isolate it before repairing or replacing the damaged component.

• Identify the source of the short circuit by checking for any burnt or damaged components

• Isolate the short circuit by disconnecting power to the affected circuit

• Repair or replace the damaged component causing the short circuit

• Test the circuit to ensure the short circuit has been resolved

FAS stands for Fire Alarm System.

• FAS is an acronym for Fire Alarm System.

• It refers to a network of devices that detect and alert people about the presence of fire or smoke.

• FAS typically includes smoke detectors, heat detectors, fire alarms, and control panels.

• These systems are crucial for early fire detection and ensuring the safety of occupants in buildings.

• Examples of FAS brands include Honeywell, Siemens, and Notifier.

AC and DC are two types of electrical current with different characteristics.

• AC stands for alternating current, while DC stands for direct current.

• AC periodically changes direction, while DC flows in one direction.

• AC is used for power transmission over long distances, while DC is used for electronic devices.

• AC can be easily converted to different voltages using transformers, while DC requires converters or inverters.

• Examples of AC sources include power grids and generators, w...read more

Artificial Intelligence is the simulation of human intelligence processes by machines, especially computer systems.

• AI involves the development of algorithms that can perform tasks that typically require human intelligence, such as visual perception, speech recognition, decision-making, and language translation.

• Machine learning is a subset of AI that focuses on the development of algorithms that allow computers to learn from and make predictions or decisions based on data.

• Exam...read more

Module VOC and VMP combination refers to the open circuit voltage and maximum power voltage of a solar panel.

• VOC (Voltage Open Circuit) is the maximum voltage that a solar panel can produce when there is no load connected.

• VMP (Voltage Maximum Power) is the voltage at which the solar panel produces the maximum power output.

• The combination of VOC and VMP is important for determining the efficiency and performance of a solar panel.

• For example, a solar panel may have a VOC of 40V...read more

Mcb is used for safety in both homes and companies. Safety wiring is essential for preventing electrical hazards.

• Mcb (Miniature Circuit Breaker) is used in homes and companies to protect electrical circuits from overloads and short circuits.

• Safety wiring, such as grounding wires and proper insulation, is crucial for preventing electrical shocks and fires.

• Proper installation and maintenance of Mcbs and safety wiring are essential for ensuring electrical safety.

• Examples: Using ...read more

ACB stands for Air Circuit Breaker which is a type of electrical protection device used in power distribution systems.

• ACB is used to protect electrical equipment from damage caused by short circuits and overloads.

• It works by automatically disconnecting the power supply when a fault is detected.

• ACBs are commonly used in industrial and commercial settings.

• They are available in different sizes and ratings to suit different applications.

• ACBs can be manually operated or remotely c...read more

VCB stands for Vacuum Circuit Breaker which is an electrical switch used for protection of electrical power systems.

• VCB uses vacuum as the arc quenching medium

• It is used for protection of electrical power systems

• It is more reliable and requires less maintenance compared to other circuit breakers

• VCB is commonly used in high voltage applications such as power stations and substations

Phase wires carry current while neutral wires complete the circuit. Voltage is the potential difference between two points.

• Phase wires are usually colored black, red, or blue while neutral wires are usually colored white or gray.

• A voltage tester can be used to determine if a wire is live or not.

• Current flows from the phase wire to the load and back to the neutral wire.

• Voltage is measured in volts and represents the potential difference between two points.

• In AC circuits, the v...read more