TM11-6125-256-34
within the operating limits selected and the output is
c To provide continuous shunt field current, essen-
continuously adjusted instantly to match the energy
tial for satisfactory motor-generator performance, the
requirements of the load
shunt field is connected to the armature dc voltage
through a diode in the regulator commonly called a
c To provide continuous field current necessary for
free-wheeling or commutating diode During the time
proper motor-generator performance, both the shunt,
that the controlling transistor is in the off state, the
and the exciter fields are connected in parallel with
field current flows through this diode, decaying only
flywheel diodes in the regulator This results in smooth
slightly until the next on state occurs
ac field current even though the regulator supplies a
pulsating square wave
a Motor-generator output is continuously monitored
a. This motor-generator may be loaded either three-
by the regulator Frequency deviations are sensed by
phase or single-phase but not simultaneously
a comparator and processed into motor-generator speed
b When used as a single-phase motor-generator, the
control signals which regulate output frequency Am-
unit shall be connected in delta (fig 2-1) and the ex-
plitude fluctuations are similarly sensed and the regu-
ternal load connected to terminals A (T1) and B (T2)
lator reacts to maintain the preset output voltage
of the ac output connecter
b Control of shunt field strength is accomplished by
c When used as a three-phase motor-generator, the
the function of switching and waveshaping timing cir-
load for each phase leg shall not differ more than 10-
cuits which form the driving pulses of the output ampli-
percent of the rated load
fier Regulation of the motor-generator is maintained
Figure 2-1. Phase connections
