Constructional Features of Split-Phase Types of Induction Motors

Question 1

Explain the reason for skewing the rotor bars relative to the slots in the stator core.

Answer 1

So the motor will run more smoothly and quietly

Question 2

At approximately what percentage of full-load speed do the centrifugal switch contacts open?

Answer 2

75%

Question 3

State the purpose of the end bells and bearings.

Answer 3

The end bells house the bearings that allow the rotor to turn freely within the stator. Together they keep the rotor in proper alignment with the stator and provide an enclosure for the motor

Question 4

Describe the construction difference between the main and auxiliary windings.

Answer 4

• The main winding is made of many turns of larger wire and is placed lower in the stator slots to give it a lower resistance and higher inductance
• The auxiliary winding is made of fewer turns of smaller wire. It is placed near the surface of the stator slots to give it a higher resistance and lower inductance