21-11-2012, 01:02 PM
Dc machine
Dc machine.ppt (Size: 317.5 KB / Downloads: 38)
Machine
That device convert electrical energy into mechanical energy and mechanical energy into electrical energy.
DC generator
PRINCIPLE OF GENERATOR
An generator is a machine which converts mechanical energy into electrical energy.
Principle of generator is the production of dynamically induced e.m.f according to FARADAY’S LAWS OF ELECTROMAGNETIC INDUCTION.
ARMATURE WINDING OR CONDUCTORS:
Armature windings consists of conductors or copper wires which are placed in slots.
It is of two types
Open coil winding and
Closed coil winding.
Open coil winding is used in A.C machines.
Closed coil winding is again divided into 2 types.
Ring winding and Drum winding.
Drum winding is again divided into two types.
Lap winding and Wave winding.
Lap winding is used for low voltages and high currents.
Wave winding is used for high voltages and low currents.
In lap and wave winding back pitch and front pitch are equal to the pole pitch.
Number of commutator segments is equal to the number of slots or coils. Pole pitch is equal to the number of conductors per pole.