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A 220V, 50 Hz, single-phase induction motor has the following connection diagram and winding orientations shown. MM' is the axis of the main stator winding (M1M2) and AA' is that of the auxiliar y winding (A1A2). Directions of the winding axes indicate direction of flux when currents in the windings are in the directions
shown. Parameters of each winding are indicated. When switch S is closed, the motor
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- rotates clockwise
- rotates anticlockwise
- does not rotate
- rotates momentarily and comes to a halt
Correct Option: C
ZAUX = r a + jxLa
= 1 + j(2π × 50) × | ||
π |
= 1 + j 1000 ∼ 1000 ∠90°

Zm = rm + jxm
= 0.1 + j (2 π × 50 ) × | ||
π |
= 0.1 + j 10 = ∠ 90°
IAUX = | = Ia ∠ -90° | |
ZAω0 |
IM = | = IM ∠ -90° | |
ZM |
∴ Starting torque = k Ia Im sin (Ia, I m)
= k' sin (θ) = 0
So motor does not rotate at starting. Obviously 1φ motor is not self starting.