Question

Arrange the following statements :
A. Stator winding is energized with balanced three phase supply
B. Spatially displaced currents create phase shifted fluxes
C. Resultant magnetic field rotates at synchronous speed
D. Rotor conductor cuts the rotating flux
E. Electromagnetic torque is produced Choose the correct answer from the options given below :

• A. A, B, C, D, E
• B. A, C, B, D, E
• C. B, C, A, D, E
• D. C, A, B, D, E

Hint:

Working sequence of a three-phase induction motor: \[ \text{3-phase supply} \rightarrow \text{Rotating magnetic field} \rightarrow \text{Induced rotor EMF} \rightarrow \text{Rotor current} \rightarrow \text{Torque production} \]

Answer 1

The Correct Option is A

Concept: This question describes the sequence of operation of a three-phase induction motor. The working principle involves:
• three phase stator excitation,
• rotating magnetic field production,
• induced rotor current,
• electromagnetic torque production.

Step 1: Starting with stator excitation. The first event is: \[ \text{Stator winding is energized with balanced three phase supply} \] This creates three alternating currents displaced by: \[ 120^\circ \] Hence: \[ A \] comes first.

Step 2: Formation of phase shifted magnetic fluxes. Due to spatial displacement of stator windings: \[ \text{Phase shifted currents produce phase shifted fluxes} \] Thus: \[ B \] comes next.

Step 3: Formation of rotating magnetic field. The combination of three phase fluxes produces: \[ \text{Resultant rotating magnetic field} \] This field rotates at: \[ N_s=\frac{120f}{P} \] Hence: \[ C \] comes after \(B\).

Step 4: Rotor conductors cutting rotating flux. The rotating magnetic field cuts rotor conductors and induces EMF according to Faraday's law. Thus: \[ D \] comes next.

Step 5: Production of electromagnetic torque. Induced rotor current interacts with rotating magnetic field. As a result: \[ \text{Electromagnetic torque is produced} \] Hence: \[ E \] comes last.

Step 6: Writing the correct sequence. Therefore the correct order is: \[ A,\;B,\;C,\;D,\;E \] Hence the correct option is: \[ \boxed{(1)} \]