Electrical Machines perguntas e respostas de entrevista
Pergunta 11. What is the difference between a motor and a generator?
A motor converts electrical energy into mechanical energy, while a generator converts mechanical energy into electrical energy.
Pergunta 12. Define the term 'cogging' in the context of induction motors.
Cogging is the phenomenon where an induction motor experiences jerky motion or hesitation at low speeds due to the interaction of rotor slots with the stator magnetic field.
Pergunta 13. How does a three-phase induction motor differ from a single-phase induction motor?
Three-phase induction motors have three windings and generate a rotating magnetic field, while single-phase induction motors have only one winding and produce a pulsating magnetic field.
Pergunta 14. What is the purpose of a capacitor in a single-phase induction motor?
A capacitor in a single-phase induction motor is used to create a phase shift, producing a rotating magnetic field necessary for starting and running the motor.
Pergunta 15. Explain the concept of back emf in DC motors.
Back emf is the voltage induced in the armature of a DC motor due to its rotation. It opposes the applied voltage and is essential for controlling motor speed.
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