DC & AC

Field Excitation

The application of a DC voltage to the field windings of a DC generator to create a steady magnetic field.

Self-Excited Generator

A DC generator that supplies its own field excitation.

Separately Excited Generator

A DC generator that relies on an external source for field excitation.

Series Wound

A type of self-excited DC generator where the field winding is connected in series to the armature.

Shunt Wound

A type of self-excited DC generator where the field winding is connected in parallel to the armature.

Compound

A type of self-excited DC generator that has both series and shunt field windings.

Long Shunt Compound

A compound DC generator where the series field is connected in series to the armature.

Short Shunt Compound

A compound DC generator where the series field is connected in series to the load.

Series Field Winding

A field winding with a few turns of large diameter wire, designed to be connected in series with the armature.

Shunt Field Winding

A field winding with many turns of small diameter wire, designed to be connected in parallel with the armature.

Residual Magnetism

The remaining magnetic energy in the field of a DC generator even when it is turned off.

Residual Voltage

The small voltage developed in the armature of a DC generator due to residual magnetism.

Flashing the Field

The process of connecting the field of a DC generator to a separate DC source to produce and retain a small amount of flux.

Saturation Curve

The relationship between field current, flux, and generated voltage in a DC generator, where increased field current no longer results in an increase in generated voltage.

Brush Contact Drop

The voltage drop over the brush contact resistance when current passes from commutator segments to brushes and finally to the external load.