The statement that the auxiliary winding is constructed differently from the main winding is:

True, because it must produce a phase-shifted current for starting

False, because the auxiliary winding has more turns

Which describes the auxiliary winding of a split-phase motor?

Thin wire, fewer turns, high R/X ratio

What if both windings were identical?

Their currents would be in phase, the field would stay pulsating and there would be no starting torque

The motor would start with higher torque

The motor would run at double speed

The centrifugal switch would not be needed and the torque would be larger

In a capacitor-start motor, the auxiliary winding is connected:

in series with a capacitor so its current leads the main winding current by nearly 90°

with no switch, running continuously at full load

2068 Bhadra · 1+3 marks

True/false: auxiliary winding construction

Short answer

True. The auxiliary winding has thinner wire, fewer turns, and higher resistance (or a series capacitor) to shift its current phase relative to the main winding, creating a rotating field for starting torque. Without this difference, no torque would be produced.

State whether the following statement is true or false and justify it: Construction of auxiliary winding of 1 phase induction motor is different from that of the main winding.

True.

In a single-phase induction motor (split-phase, capacitor-start or capacitor-run type), the auxiliary winding is built differently from the main winding, because it has to carry a current that is phase-shifted from the main winding current, and (except in capacitor-run motors) it is used only for starting.

Main winding: thick wire, many turns, low resistance and high reactance (low R/X ratio). Its current lags V by a large angle.
Auxiliary winding in a split-phase motor: thin wire, fewer turns, high resistance and low reactance (high R/X ratio), so its current lags V by a smaller angle. The winding carries current only for a short time, so a thinner wire is acceptable.
In capacitor motors: the turns and wire size of the auxiliary winding are chosen to suit the series capacitor, so that its current leads the main winding current by nearly 90°.
The auxiliary winding is placed 90° (electrical) from the main winding in the stator slots, and in split-phase and capacitor-start motors it is disconnected by a centrifugal switch at about 75 % of synchronous speed.

If the two windings were identical, their currents would be in phase and the net field would still be pulsating, not rotating, giving no starting torque. The difference in construction creates the phase difference needed.

✓ Answer checked by Claude Opus 5.5 (high effort)

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