Luman Industries Interview Questions and Answers

A circuit breaker is an electrical switch that automatically interrupts the flow of current when it exceeds a certain limit.

• It is used to protect electrical circuits from damage caused by overloading or short circuits.

• It works by detecting the excess current and tripping the switch to break the circuit.

• It can be reset manually or automatically depending on the type of circuit breaker.

• Examples include thermal circuit breakers, magnetic circuit breakers, and hydraulic-magnetic ...read more

A current transformer is a device that measures the current flowing in a circuit by producing a proportional current in its secondary winding.

• Consists of a primary winding and a secondary winding

• Primary winding is connected in series with the circuit carrying the current to be measured

• Secondary winding is connected to a measuring instrument or protective relay

• Produces a current in the secondary winding that is proportional to the current in the primary winding

• Used for current...read more

A motor is a device that converts electrical energy into mechanical energy to produce motion.

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

• There are different types of motors such as DC motors, AC motors, stepper motors, and servo motors.

• The basic principle of a motor is the interaction between a magnetic field and an electric current.

• Examples of motors include ceiling fans, washing machines, and electric car...read more

A contactor is an electrical switch used for switching an electrical circuit on or off.

• It is used to control electric motors, lighting, heating, and other electrical loads.

• It consists of a coil, contacts, and an enclosure.

• The coil generates a magnetic field that pulls the contacts together to close the circuit.

• Examples include HVAC systems, elevators, and industrial machinery.

• Contactor ratings are based on the amount of current they can handle and the voltage they can switch....read more

MCB stands for Miniature Circuit Breaker. It is an electrical switch that automatically shuts off the electrical circuit during an overload or short circuit.

• MCB is a type of circuit breaker that is commonly used in residential and commercial buildings.

• It is designed to protect electrical circuits from damage caused by overloading or short circuits.

• MCBs are available in different current ratings and can be easily replaced if they trip.

• They are more reliable and faster in tripp...read more

Electrical motors are devices that convert electrical energy into mechanical energy. There are various types of electrical motors.

• DC motors - used in appliances, toys, and automobiles

• AC motors - used in industrial machinery and household appliances

• Stepper motors - used in robotics and automation

• Servo motors - used in precision control applications

• Brushless DC motors - used in drones and electric vehicles

Rotating parts of a machine are components that move in a circular motion, such as motors, turbines, or fans.

• Rotating parts are typically components like motors, turbines, fans, or rotating shafts.

• Non-rotating parts include components like housings, casings, brackets, or stationary supports.

• Non-rotating parts are usually fixed in place and provide support or protection for the rotating components.

• Examples of non-rotating parts include the frame of a motor, the casing of a tur...read more