L.G.Balakrishnan & Bros Electrical Technician Interview Questions and Answers

Power factor is a measure of how effectively electrical power is being used in a circuit.

• Power factor is the ratio of real power (in watts) to apparent power (in volt-amperes).

• It indicates the efficiency of electrical power consumption in a circuit.

• A power factor of 1 means all the power is being used effectively, while a power factor less than 1 indicates wastage of power.

• Inductive loads like motors and transformers h...read more

A motor is an electrical device that converts electrical energy into mechanical energy.

• Motors are used in a variety of applications, from powering industrial machinery to driving household appliances.

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

• Motors can be controlled using various methods, such as variable frequency drives and soft starters.

• Proper maintenance and inspection ...read more

A star delta starter is used to reduce the starting current of a motor.

• The motor is initially connected in star configuration to reduce the voltage across each winding.

• After a set time, the motor is switched to delta configuration for normal operation.

• The control diagram includes a timer, contactors, and overload protection.

• The timer delays the switching from star to delta configuration.

• The contactors are used to switc...read more

DOL starter is used in single-phase induction motors and small three-phase motors.

• DOL starter stands for Direct-On-Line starter.

• It is used to start and stop the motor directly without any intermediate control.

• It is commonly used in single-phase induction motors and small three-phase motors.

• DOL starter provides full voltage to the motor during starting, which can cause high starting current.

• It consists of a contactor, t...read more

The resistive load equation is used to calculate the power consumed by a resistive load.

• The equation is P = V^2/R, where P is power, V is voltage, and R is resistance.

• This equation is used in electrical engineering to determine the power consumption of resistive loads such as heaters and incandescent light bulbs.

• The equation can also be rearranged to solve for voltage or resistance, depending on the information given.

• I...read more

Asynchronous motors are used for various purposes due to their simple design and low cost.

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

• They are also used in household appliances like washing machines and refrigerators.

• Asynchronous motors are preferred for their low maintenance and high reliability.

• They are also used in electric vehicles and hybrid cars.

• Asynchrono...read more

Transformers are classified based on their construction, purpose, and voltage level.

• Based on construction: core type, shell type, and Berry type

• Based on purpose: power transformer, distribution transformer, isolation transformer, autotransformer, etc.

• Based on voltage level: step-up transformer, step-down transformer, and isolation transformer

• Other classifications: single-phase transformer, three-phase transformer, and ...read more

India has a total installed capacity of over 370 GW as of 2021.

• India's power generation capacity has been growing rapidly in recent years

• The country has set a target of achieving 450 GW of renewable energy capacity by 2030

• India is one of the world's largest producers of renewable energy, with a capacity of over 100 GW

• Coal still accounts for a significant portion of India's power generation, but the government is workin

Chopper circuits are used to convert a fixed DC voltage to a variable DC voltage.

• Chopper circuits are also known as DC-DC converters.

• They are used in applications such as battery charging, motor control, and renewable energy systems.

• Chopper circuits use high-frequency switching to control the output voltage.

• Examples of chopper circuits include buck converters, boost converters, and buck-boost converters.