DC GENERATORS UNIT 30 DELMAR'S STAND TEXTBOOK OF ELECTRICITY 6TH EDITION

Output Voltage

Can be increased by number of turns for each loop or more than one loop of wire

Rectified DC Voltage

During this 360 degree rotation of the loop the polarity of voltage remained the same for both hlaves of the waveform.

Frogleg Wound Armatures

Most used in machines designed for use with moderate current and moderate voltage. Connected in series-parallel Most large DC machines use frogleg wound armatures.

Neutral plane

Position at which the windings are parallel to the lines of flux and there's no induced voltage.

Brushes

Ride against the commutator segments and are used to connect the armature to the external circuit of the DC machine. Brush leads are generally marked A1 and A2 and are referred to as the armature leads

Field Windings (Series Field VS. Shunt Field)

Series Field VS. Shunt Field Series Field windings are made with relatively few turns of very large wire and have a very low resistance and wired in series with the armature. S1 and S2 Shunt Field Made with many turns of small wire because it is constructed with small wire with much higher resistance than the series field. Connected in parallel

iron Core

The loops are gnerally placed in slots of an inron core. Acts as a magnetic conductor by providing a low reluctance path for magnetic lines of flux to increase the inductance of the lloops and provide a higher induced voltage.

Generator

is a device that converts mechanical energy into electric energy.

Pole Pieces

located inside the housing of the DC machine Pole pieces provide the magnetic field necessary for the operation of the machine DC generator that uses permanent magnets as its field is referred to as a magneto

Commutator

• Maintains proper polarity • Converts AC Current to DC Current

Wave - Wound Armatures

• Used in machines designed for high voltage and low current. • Windings connected in series • When the windinsg are connected in series, the voltage of each winding adds, but the current capacity remains the same. • Never contain more than two paralllel paths for current flow regardless of the number of pole pieces, and they never contain more than one set of brushes (a set being one brush or groupl of brushes for positive and one brush or group of brushes for negative)

Lap Wound Armatures

• Used in machines designed for low voltage and high current. • Constructed with large wires because of high current. • Windings connected in Parallel and this permits the current capacity of each windings to be added and provides • Lap Wound armatures have as many parallel path through the armature as there are pole pieces.