SOLUTION

In a split-phase motor, the auxiliary winding is made up of thin wire placed at top of the slot.

Split-Phase Motors

• Split-phase motors receive their name from the manner in which they operate, based on the principle of the rotating magnetic field.
• A rotating magnetic field cannot be produced with only one phase.
• The current is split through two separate windings with a phase displacement, which acts like a 2-phase system.
• A rotating magnetic field can be produced with a 2-phase system. Split-phase motors start as 2-phase motors by producing an out-of-phase condition for the current in the run winding and the start winding.
• The starting winding is wound in the same slots of the stator poles as the running windings.
• This starting winding is displaced 90 electrical degrees out of phase with the running winding and creates a phase displacement that provides enough starting torque to start the motor.

• A startup winding, also known as the auxiliary winding, is used to create the torque needed to start a single-phase induction motor.
• The starting winding is of higher resistance made up of thin wire and occupies a smaller area than the running winding.
• In comparison, the running winding is of lower resistance and has heavier gauge wire and more turns than the starting winding.
• The running winding is wound in the bottom of the stator pole slots, and the starting winding is wound on top of the running winding.