Under what condition would a 'wye-delta' starter typically be preferred over a 'direct-on-line' (DOL) starter for a 3-phase induction motor?

Question: Under what condition would a 'wye-delta' starter typically be preferred over a 'direct-on-line' (DOL) starter for a 3-phase induction motor?

Answer options: ✅ When the utility imposes limits on motor starting current.

• When the motor always operates at full load.
• When precise speed control of the motor is required.
• When space is extremely limited for the motor control centre.

Correct answer: When the utility imposes limits on motor starting current.

Explanation: Wye-delta starters are a type of reduced voltage starter commonly used to limit the high inrush current that occurs when a large motor is started direct-on-line. By initially connecting the motor windings in a wye configuration, the starting current and torque are reduced, which helps to comply with utility regulations and reduce mechanical stress on the driven equipment. Wye-delta starters do not offer precise speed control; that is the function of a Variable Frequency Drive (VFD). Full load operation or limited space are not the primary considerations for choosing a wye-delta starter.