introduction to rotating machines

1. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES BASIC MACHINE TYPES :

2. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES DYNAMICALLY INDUCED EMF : Electromechanical energy conversion takes place whenever a change in flux linkages is associated with mechanical motion. Voltage is generated in a coil when there is a relative movement between the coil and magnetic field. The Field Winding, which are the primary source of flux in the machine. They are arrange to produce cyclic North-South space distribution of Poles. Coils are several in number in practical machines and are suitably distributed and connected in series/parallel and in star/delta 3-φ connection to give desired Voltage and to supply rated Current; this arrangement is called Armature Winding.

3. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES WHERE TO PLACE FIELD & ARMATURE WINDINGS ? Stationary Member Rotating Member STATOR ROTOR

4. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES ROTATING MACHINES : Electric Generator (TPM=TG) : TPM :Prime mover Torque TG: Generator Torque Electric Motor (TM=TL) : TM :Motor Torque TL: Load Torque

5. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES CONSTRUCTIONAL FEATURES : STATOR ROTOR Field Winding Armature WindingIn General In Case of Synchronous Machines Field WindingArmature Winding These are DC exited to produce alternate N-S poles in pairs The interaction between primary field and current carrying armature conductors causes production of torque of electromagnetic origin.

6. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES Salient-pole Rotor Non-Salient-pole Rotor (Cylindrical Rotor) For Low Speed Applications For High Speed Applications

7. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES 1. Field wdgs are placed on rotor and stator carries armature wdgs. 2. The field wdgs are excited through slip-rings from a DC Source. 3. Generally a small DC Generator called exited is coupled to the shaft of the synchronous machine.

8. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES 1. Field wdgs are placed on stator and Rotor carries armature wdgs. 2. AC voltages and Currents induced in the armature wdg has to converted to DC using rotational mechanical converter called commutator.

9. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES 1. The stator carries 3-φ wdg , which when excited by 3-φ ac source that sets up rotating flux pattern with N-S poles in the air-gap at synchronous speed. 2. Armature wdgs are short circuited.

10. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES FLUX DENSITY DISTRIBUTION IN ELECTRICAL MACHINES: To generate Sinusoidal flux , the pole faces in such a machine are there fore CLAMPERED.

11. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES ELECTRICAL Vs MECHANICAL ANGLES: θele = (P/2) θ mech

12. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES FLUX DENSITY DISTRIBUTION IN ELECTRICAL MACHINES: Another method of achieving a nearly sinusoidal B-wave is to use cylindrical rotor structure.

13. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES THREE PHASE ALTERNATOR (GENERATOR )- WINDING TYPES

14. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES THREE PHASE ALTERNATOR (GENERATOR )- WINDING TYPES θele = (P/2) θ mech

15. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES TYPES OF WINDINGS

21. Mr. D. GaneshElectrical Science – II INTRODUCTION TO ROTATING MACHINES

introduction to rotating machines

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introduction to rotating machines