An induction motor can be said analogous to

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transformer

Explanation: An induction motor is considered a generalized transformer with a rotating secondary. Like a transformer, the primary (stator) induces a voltage in the secondary (rotor) via electromagnetic induction without any direct electrical connection.

Working Principle: In a transformer, the primary winding produces a time-varying magnetic field that links with the stationary secondary. In an induction motor, the stator winding (primary) creates a rotating magnetic field (RMF) that induces emf in the rotor conductors (secondary). The fundamental difference is that the induction motor includes a mechanical degree of freedom (rotor motion) to convert electrical power into mechanical torque.

Key Formulas: $s = \frac{N_s - N_r}{N_s}$ — Slip calculation in induction motors; $E_2 = 4.44 f \Phi N_2$ — Induced emf equation principle analogous to transformers

Key Points: Both devices rely on Faraday's Law of Electromagnetic Induction.; The stator of the induction motor acts as the primary winding of a transformer.; The rotor of the induction motor acts as the secondary winding.; Energy transfer is purely inductive, requiring no physical contact between stator and rotor.

Advantages: Rugged construction; Self-starting capability (in most polyphase designs); Low maintenance due to absence of brushes

Disadvantages: Cannot operate at exactly synchronous speed; Requires reactive power for excitation

Applications: Industrial pumps and fans; Conveyor systems; Compressors

Additional Info: The induction motor is essentially a 'rotating transformer' where the secondary frequency changes with slip.. Option B is incorrect because a synchronous motor requires DC excitation for the rotor.. Option C is a series-wound commutator motor capable of operating on AC or DC.. Option D is a precise position-control motor with discrete rotational steps.

Answer: A is correct — The induction motor operates on the principle of electromagnetic induction exactly like a transformer, with the stator acting as the primary and the rotor as the secondary.

Exam Tip: Always remember that in an induction motor, if the rotor is locked ($N_r = 0$), it behaves exactly as a short-circuited transformer.

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