Dakshinanchal Vidyut Vitran Nigam Interview Questions and Answers

DC motor works on the principle of Lorentz force.

• DC motor converts electrical energy into mechanical energy.

• It consists of a rotor and a stator.

• When current flows through the coil, it produces a magnetic field.

• The magnetic field interacts with the magnetic field of the permanent magnet, producing a torque that rotates the rotor.

• The direction of rotation can be reversed by reversing the direction of current flow.

Commutator is a device used in electric motors to convert AC to DC.

• It consists of a set of copper segments attached to the rotor of the motor.

• It helps in reversing the direction of current flow in the armature winding.

• It ensures that the torque produced by the motor is unidirectional.

• Examples include DC motors, generators, and some types of welding machines.

Back EMF is directly proportional to speed and number of poles in a DC motor.

• Back EMF is generated in the opposite direction to the applied voltage.

• As the motor speeds up, the back EMF increases.

• The number of poles in the motor determines the frequency of the back EMF.

• More poles result in a higher frequency and a smoother rotation.

• Back EMF is used to control the speed of the motor.

Slipring and squirrel cage induction motors differ in their rotor construction and starting torque.

• Slipring motor has a wound rotor with slip rings and brushes while squirrel cage motor has a simple rotor with bars and end rings.

• Slipring motor has high starting torque and can be used for heavy loads while squirrel cage motor has low starting torque and is suitable for light loads.

• Slipring motor can be controlled by var...read more

Synchronous motors rotate at a fixed speed while slipring induction motors have variable speed.

• Synchronous motors have a constant speed and require an external power source to start

• Slipring induction motors have a variable speed and can start on their own

• Synchronous motors are used in applications where constant speed is required, such as in clocks and timers

• Slipring induction motors are used in applications where vari...read more

Speed, frequency and number of poles are interrelated in a 3-phase induction motor.

• The speed of the motor is directly proportional to the frequency of the power supply.

• The number of poles in the motor determines the speed at which it operates.

• For a given frequency, the speed of the motor decreases as the number of poles increases.

• For a given number of poles, the speed of the motor increases as the frequency of the powe

Fleming's left-hand rule states that the direction of motion of a DC motor is perpendicular to both the magnetic field and the direction of current flow.

• Fleming's left-hand rule is used to determine the direction of motion of a DC motor.

• The rule states that the direction of motion is perpendicular to both the magnetic field and the direction of current flow.

• The thumb represents the direction of motion, the first finger...read more

Yes, I play video games in my free time.

• I enjoy playing action-adventure games like Assassin's Creed and Uncharted.

• I also like playing sports games like FIFA and NBA 2K.

• Sometimes I play puzzle games like Tetris or Candy Crush.

• Playing video games helps me relax and unwind after a long day.

My native place is famous for its ancient temples and rich cultural heritage.

• The city has a famous temple dedicated to Lord Shiva

• The annual cultural festival attracts tourists from all over the world

• The city is known for its traditional dance forms and music

• The local cuisine is a blend of different flavors and spices

• The city has a rich history dating back to the ancient times

Internal combustion engines burn fuel inside the engine while external combustion engines burn fuel outside the engine.

• Internal combustion engines are commonly used in cars, motorcycles, and airplanes.

• External combustion engines are less common and include steam engines and Stirling engines.

• Internal combustion engines are more efficient and powerful than external combustion engines.

• External combustion engines are typic...read more