Figure 1-22.Ordinary dc generator.
Assume that the characteristics of this generator enable it to produce approximately 87 amperes of
armature current at 115 volts at the output terminals. This represents an output power of approximately
10,000 watts (P = IE). You can see that the power gain of this generator is 100. In effect, 100 watts
controls 10,000 watts.
An amplidyne is a special type of dc generator. The following changes, for explanation purposes,
will convert the typical dc generator above into an amplidyne.
The first step is to short the brushes together, as shown in figure 1-23. This removes nearly all of the
resistance in the armature circuit.
Figure 1-23.Brushes shorted in a dc generator.
Because of the very low resistance in the armature circuit, a much lower control-field flux produces
full-load armature current (full-load current in the armature is still about 87 amperes). The smaller control