Bangalore Electricity Supply Company Electrical Technician Interview Questions and Answers

An overload relay works by monitoring the current flowing through a motor and tripping when the current exceeds a set limit.

• Monitors the current flowing through a motor

• Trips and interrupts power when current exceeds a set limit

• Protects the motor from damage due to overloading

• Can be reset manually after tripping

Insulation resistance is measured using a megohmmeter to apply a high voltage and measure the resistance of the insulation material.

• Use a megohmmeter to apply a high voltage to the insulation material

• Measure the resistance of the insulation material to determine its insulation resistance

• Insulation resistance is typically measured in megaohms (MΩ)

• Regular insulation resistance testing helps prevent electrical failures an

Electrical safety can be ensured by following proper procedures, using appropriate equipment, and staying vigilant.

• Always use insulated tools when working on live circuits

• Ensure circuits are de-energized before working on them

• Wear appropriate personal protective equipment (PPE) such as gloves and goggles

• Regularly inspect and maintain electrical equipment to prevent malfunctions

• Follow safety guidelines and procedures ou

Preventive maintenance on a motor involves inspecting, cleaning, lubricating, and testing the motor to ensure optimal performance and prevent breakdowns.

• Inspect the motor for any signs of wear or damage

• Clean the motor and its components to remove dirt and debris

• Lubricate moving parts to reduce friction and wear

• Test the motor's performance using appropriate tools and equipment

• Replace any worn out parts or components as

To succeed in an interview, it is important to prepare thoroughly, practice common interview questions, research the company, dress professionally, and demonstrate enthusiasm and confidence.

• Thoroughly research the company and the position you are applying for

• Practice common interview questions and prepare examples of your skills and experiences

• Dress professionally and appropriately for the interview

• Demonstrate enthusia...read more

A star-delta starter is used to reduce the starting current of a motor by initially connecting the motor windings in a star configuration and then switching to a delta configuration.

• The motor windings are initially connected in a star configuration during starting to reduce the starting current.

• After a certain period, the windings are switched to a delta configuration to achieve full speed and torque.

• This transition fr...read more

Undervoltage faults occur when the voltage in a system drops below the normal operating level, leading to potential equipment damage or malfunction.

• Undervoltage faults can be caused by issues such as power supply fluctuations, equipment failures, or overloaded circuits.

• These faults can lead to equipment damage, reduced efficiency, or complete shutdown of systems.

• Examples include a power surge causing a drop in voltage,...read more

Overvoltage faults are electrical faults that occur when the voltage in a circuit exceeds the normal operating range.

• Overvoltage faults can damage electrical components and equipment.

• They can be caused by lightning strikes, power surges, or faulty equipment.

• Protective devices like surge protectors and voltage regulators can help prevent overvoltage faults.

• Examples include a power surge from a lightning strike damaging ...read more

A thermal relay is used to protect electrical circuits from overloads by monitoring the temperature of the circuit and tripping when it exceeds a certain threshold.

• Monitors the temperature of the electrical circuit

• Trips and disconnects the circuit when temperature exceeds a set limit

• Protects against overloads and overheating

• Commonly used in motor protection applications

An RDOL starter is a type of reduced voltage starter used in electrical systems to reduce the starting current and torque of a motor.

• RDOL stands for Reduced Direct Online starter.

• It is used to start induction motors in a controlled manner.

• RDOL starters reduce the voltage supplied to the motor during starting to limit the inrush current.

• This helps in reducing mechanical stress on the motor and connected equipment.

• Common...read more

A motor in electrical engineering is a device that converts electrical energy into mechanical energy.

• Motors are commonly used in various applications such as industrial machinery, household appliances, and electric vehicles.

• There are different types of motors including DC motors, AC motors, and stepper motors.

• Motors consist of a rotor and a stator, with the rotor rotating when electrical current is applied.

• The speed an...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 named after Georg Simon Ohm, a German physicist who first formulated this law.

• This law is applicable to all types of circuits, including DC and AC circuits.

• It is use...read more

An induction motor is a type of AC motor where power is supplied to the rotor by electromagnetic induction.

• Induction motors are commonly used in various applications such as industrial machinery, pumps, fans, and compressors.

• They do not require brushes to transfer power to the rotor, making them more reliable and maintenance-free compared to brushed DC motors.

• The speed of an induction motor is determined by the frequen...read more

A DC series motor is a type of DC motor where the field winding is connected in series with the armature winding.

• Field winding and armature winding are connected in series

• High starting torque but low speed

• Used in applications where high starting torque is required, such as in traction applications

Various methods exist to measure motor RPM, including tachometers, frequency counters, and optical sensors.

• Tachometer: A device that directly measures the rotational speed of the motor shaft.

• Frequency Counter: Measures the frequency of the motor's output signal, which can be converted to RPM.

• Optical Sensor: Uses light beams to detect the rotation of a marked disk attached to the motor.

• Stroboscope: A flashing light that...read more

Safety devices in conveyor systems prevent accidents and ensure smooth operation, protecting both workers and equipment.

• Emergency Stop Buttons: Allow immediate shutdown of the conveyor in case of an emergency.

• Safety Guards: Physical barriers that prevent access to moving parts, reducing the risk of injury.

• Photoelectric Sensors: Detect objects or personnel in the conveyor's path, stopping operation if necessary.

• Overload...read more

The negative charge of an ESP system electrode helps in attracting and collecting particulate matter from flue gases.

• Electrostatic Precipitators (ESPs) use negatively charged electrodes to ionize particles in the gas stream.

• The negative charge creates an electric field that attracts positively charged particles, aiding in their collection.

• For example, in power plants, ESPs remove ash and other pollutants from exhaust g...read more

Healthy silica gel is typically blue or orange, while unhealthy silica gel turns pink or green, indicating moisture absorption.

• Healthy silica gel is often blue or orange, indicating it is dry.

• Unhealthy silica gel turns pink or green when it absorbs moisture.

• Blue silica gel contains cobalt chloride, which changes color when wet.

• Orange silica gel is a safer alternative that changes from orange to green when saturated.

MCC stands for Motor Control Center and PCC stands for Power Control Center. They are electrical panels used to control and distribute power to motors and other electrical equipment.

• MCC panels are used to control and distribute power to motors in industrial settings.

• PCC panels are used to control and distribute power to various electrical equipment.

• Both panels play a crucial role in ensuring efficient and safe operatio...read more

A motor is a device that converts electrical energy into mechanical energy to perform work.

• Motors are commonly used in various applications such as electric vehicles, industrial machinery, and household appliances.

• They come in different types such as AC motors, DC motors, and stepper motors.

• Motor capacity refers to its power rating, typically measured in horsepower (HP) or kilowatts (kW).

• Higher capacity motors can gene...read more