-:Synchronous Generator/Alternator :-
Synchronous generator is defined as -
" A electrical machine which used for converting mechanical power from a prime mover to A.C ( Alternating Current ) electric power at a specific voltage and frequency is known as synchronous generator or alternator " .
Construction of Synchronous Generator:-
Similar to other rotating machines , an alternator consists of two main parts namely , the stator and the rotor , their construction are as follows :-
1- Stator Construction:- The various parts of the stator include the frame , stator core , stator winding and cooling arrangement . The frame may be of welded steel type for large size machines . In order to reduce hysteresis and eddy-current losses , the stator core is assembled with high grade silicon content steel lamination .
2- Rotor Construction :- There are two types of rotor given as -
(i)- Salient - Pole Rotor
(ii)- Cylindrical Rotor
(i)- Salient - Pole Rotor:- A salient pole rotor consists of poles projecting out from the surface of the rotor core . Salient pole rotors are normally used for rotors with four or more poles . The poles are built up of thick steel lamination and bolted to the rotor as shown in figure -
Salient - pole alternators driven by water turbine are called hydro-alternators or hydro-generators .
(ii)- Cylindrical Rotor :- A cylindrical rotor machine is also called a non-salient pole rotor machine . This rotor consists of smooth solid steel cylinder , having number of slots accommodate the field coil . These slots are covered at the top with the help of steel manganese wedges .
Following figure shows 2-pole and 4-pole cylindrical rotors .
Working of Synchronous Generator :- Synchronous generator is works on the principle of electromagnetic induction i.e. when the magnetic flux is cut by a conductor , an emf ( electromagnetic force ) is induced in the conductor .
In practical synchronous alternator , the field magnets rotate between the stationary armature conductors . Since the rotor and shaft or turbine blades are mechanically coupled to each other and rotates at synchronous speed . Thus , the magnetic flux cutting produces an induced emf which causes the current flow in armature conductors . Thus for each winding the current flow in one direction for the first half cycle and current flows in the other direction for the second half cycle with a time lag of 120º .
Application of Alternators :-
1- Synchronous generators are used for generation of 3𝚽 power at all the generating stations . Ex- Turbo-generators and Hydro-generators .
2- Large synchronous generators are used to generate bulk power at thermal , hydro and nuclear power stations .
Synchronous generator is defined as -
" A electrical machine which used for converting mechanical power from a prime mover to A.C ( Alternating Current ) electric power at a specific voltage and frequency is known as synchronous generator or alternator " .
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Construction of Synchronous Generator:-
Similar to other rotating machines , an alternator consists of two main parts namely , the stator and the rotor , their construction are as follows :-
1- Stator Construction:- The various parts of the stator include the frame , stator core , stator winding and cooling arrangement . The frame may be of welded steel type for large size machines . In order to reduce hysteresis and eddy-current losses , the stator core is assembled with high grade silicon content steel lamination .
2- Rotor Construction :- There are two types of rotor given as -
(i)- Salient - Pole Rotor
(ii)- Cylindrical Rotor
(i)- Salient - Pole Rotor:- A salient pole rotor consists of poles projecting out from the surface of the rotor core . Salient pole rotors are normally used for rotors with four or more poles . The poles are built up of thick steel lamination and bolted to the rotor as shown in figure -
(ii)- Cylindrical Rotor :- A cylindrical rotor machine is also called a non-salient pole rotor machine . This rotor consists of smooth solid steel cylinder , having number of slots accommodate the field coil . These slots are covered at the top with the help of steel manganese wedges .
Following figure shows 2-pole and 4-pole cylindrical rotors .
Working of Synchronous Generator :- Synchronous generator is works on the principle of electromagnetic induction i.e. when the magnetic flux is cut by a conductor , an emf ( electromagnetic force ) is induced in the conductor .
In practical synchronous alternator , the field magnets rotate between the stationary armature conductors . Since the rotor and shaft or turbine blades are mechanically coupled to each other and rotates at synchronous speed . Thus , the magnetic flux cutting produces an induced emf which causes the current flow in armature conductors . Thus for each winding the current flow in one direction for the first half cycle and current flows in the other direction for the second half cycle with a time lag of 120º .
Application of Alternators :-
1- Synchronous generators are used for generation of 3𝚽 power at all the generating stations . Ex- Turbo-generators and Hydro-generators .
2- Large synchronous generators are used to generate bulk power at thermal , hydro and nuclear power stations .
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