The document discusses the key differences between DC generators and alternators, emphasizing that a DC generator produces alternating e.m.f. in its armature conductors which is converted to DC via a commutator. Without the commutator, the machine becomes an alternator, providing AC e.m.f. directly. It also touches on the types of coils used in generators, specifically full and short-pitched coils.

1. Synchronous Generator
P R A S H A N T K U M A R S C H I N A M A L L I
A S S I S T A N T P R O F E S S O R , S E N I O R I E E E
M E M B E R
D E P A R T M E N T O F E L E C T R I C A L &
E L E C T R O N I C S E N G I N E E R I N G
F A C U L T Y O F E N G I N E E R I N G A N D
T E C H N O L O G Y ( C O - E D )
S H A R N B A S V A U N I V E R S I T Y , K A L A B U R A G I

2. Difference between DC generator
and Alternator
•
It is seen that in case of a D.C. generator, basically the nature of the induced E.M.F. in the
armature conductors is of alternating type. By using commutator and brush assembly it is
converted to D.C. and made available to the external circuit. If commutator is dropped from a
dc. generator and induced E.M.F. is tapped from an armature directly outside, the nature Of
such E.M.F. will be alternating. Such a machine without commutator, providing an A.C. E.M.F.
to the external circuit is called an alternator.

12. As against this if coils are Full pitch coil used in such a way that coil span is slightly less
than a pole pitch i.e. less than 180°electrical, the coils are called, short pitched coils or
fractional pitched coils. Generally coils are shorted by one or two slots

23. Voltage Regulation of Alternators