1. Three-phase Cage Rotor Induction Motors Resource 2 Three-Phase AC machines

2. Aims Three-phase Cage Rotor Induction Motors 1. To understand the principle of the operation of the motor 2. To describe the construction of a cage rotor induction commercial motor 3. To understand the factors that affect the performance of the motor Three-Phase AC Machines Resource 2

3. Objectives At the end of this lesson you should be able to: Describe the principle of the rotating magnetic field Describe the principle of rotor cage induction Describe the construction of a commercial stator Describe the construction of a commercial cage rotor Explain and calculate synchronous speed Explain and calculate fractional slip Describe the effect upon the performance of the motor by connecting the stator in star and delta Performance simple calculations involving electrical and mechanical parameters that describe the performance of the motor Describe the performance curve for a cage rotor induction motor Three-phase Cage Rotor Induction Motors Three-Phase AC Machines Resource 2

4. 1. Motor Shaft 2. Name plate 3. Key and Keyway Three-phase Cage Rotor Induction Motors Three-Phase AC Machines Resource 2 Construction of Commercial Motor 4. Bearings 5. Terminal Box 6. Lifting eye 7. Laminated Rotor 8. Air flow intake 9. Cooling Fan 10. Mounting base 11. Cooling fins 12. Stator coils 123456789101112

5. Three-phase Cage Rotor Induction Motors Three-Phase AC Machines Resource 2 Rotor cage Copper age rotator bars Embedded within laminated Steel discs The complete rotor assembly Shaft Copper end ring Laminated steel discs

6. Stator Made of laminated iron slotted rings Slots insulated with Mylar sheet Coils inserted into slots Three-phase Cage Rotor Induction Motors Three-Phase AC Machines Resource 2

7. 2. Construction of Commercial Motor STARDELTA Link A’, B’ and C’ Link A’ with B, B’ with C and C’ with A Three-phase Cage Rotor Induction Motors Three-Phase AC Machines Resource 2 Stator coil connections