Figure 5-2. Generator drive assembly, Ohmmeter ZM-21/U.
actually a series voltage regulator with terminal 1
as the input, terminal 2 as the output, and ter-
The controller (fig. 5-3) is an electronic circuit
minal 3 as the common. The controller is used in
contained in a sealed plastic box which limits the
some models of ZM-21A/U and all of ZM-21B/U.
output voltage of the generator to 525 volts. It is