1 / 12

Three-Phase AC machines

Three-Phase AC machines. Resource 6. Three-Phase Wound Rotor Induction Motors. Three-Phase Wound Rotor Induction Motors. Three-Phase AC Machines Resource 6. Aim. To understand the construction, operation and performance of a Three-Phase Wound Rotor Induction Motor.

lbook
Download Presentation

Three-Phase AC machines

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Three-Phase AC machines Resource 6 Three-Phase Wound Rotor Induction Motors

  2. Three-Phase Wound Rotor Induction Motors Three-Phase AC Machines Resource 6 Aim • To understand the construction, operation and performance of a Three-Phase Wound Rotor Induction Motor

  3. Three-Phase AC Machines Resource 6 Three-Phase Wound Rotor Induction Motors Objectives • To be able to describe the construction of a three-phase wound rotor induction motor • To be able to describe the operation of a three-phase wound rotor induction motor • To be able to describe the performance of a three-phase wound rotor induction motor

  4. Motor Construction 1 Outside View 1. Terminal Box 2. Outer Casing 7 3. Mounting Bolts 2 4. Inspection Cover 5. Air Intake Vents 6 6. End Plate 3 5 4 7. Rotor Shaft

  5. Motor Construction 2 1 Terminal Box 1. Rotor Terminals K, L, M 2. Stator Terminals U1, V1, W1 3 3. Stator Windings 4. Stator Terminals U2, V2, W2 5. Rotor Windings 4 5 6 6. Earth Terminal

  6. Motor Construction 1 The Stator 1. Motor Outer Casing 2. Stator Coils 2 6 3. Stator Slots 4. Air Intake Vents 3 5. Stator Laminations 5 6. Slots Insulators 4

  7. Motor Construction The Rotor 1. Rotor Coils 2. Slip Rings 3. Brushes 4. Rotor Terminals 5. Rotor Laminations 6. Rotor Slots

  8. Motor Construction The Rotor 3 2 1 1. Slip Rings 2. Rotor Coils 3. Cooling Fan 4. Rotor Slots 5. Bearing 4 5

  9. Motor Construction 6 The Brush Gear 1 1. Brass Brush Holders 2. Carbon Brushes 5 2 3. Springs 4. Nylon Insulator 5. Rotor Terminals 6. External Connecting Wires 3 4

  10. Motor Operation The Rheostat Method of Starting 1. Motor starts with 3-gang Rheostat set to highest resistance giving low starting current and slow speed. 2. The Rheostat is adjusted slowly thus reducing rotor resistance to zero. 3. This increases rotor speed up to its maximum value 4. Starting torque can be easily adjusted by initial resistance setting to suit the load.

  11. Motor Operation Stator Connections The Contactor Method of Starting 1. Motor starts with 3 resistors in each rotor circuit giving low starting current and slow speed. Earth Terminal Shorting Relays K1, K2, K3 Rotor Connections 2. K3 is energised shorting out resistors R31, R32, R33 giving increased speed. Rotor Resistor Bank 1 3. K2 is energised shorting out resistors R21, R22, R23 giving increased speed. Rotor Resistor Bank 2 4. K1 is energised shorting out resistors R11, R12, R13 giving full speed. Rotor Resistor Bank 3

  12. Motor Performance Torque-Speed Curve for a four pole motor Increasing Rotor Resistance 1. Does not change synchronous speed 2. Does not change maximum torque 3. Increases Starting Torque 4. Decreases Speed in running region for given load 5. Decreases Speed where maximum torque occurs 6. Decreases Starting Current

More Related