Radar System Engineering

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SEC. 14.5] VOLTAGE REGULATORS 565
Bell Telephone Laboratories developed a regulated exciter, type
KS-15055, which weighed about 12 lb complete and was meant for use
with the PE-218 inverter. (See Fig. 14.7.) It regulated the 115-volt
output to about ~ 0.5 volt rms, but had a rather slow response and only
fair temperature compensation. The temperature compensation was
improved in a later model.
General Electric Company developed a similar regulator, type
3GVA1OBY1, for use with PE-218-D inverters; it used a saturated-diode
voltage-sensitive element. (See Fig. 148.) This regulated the 115-volt
output to about + 0.1 volt rms and had good response and temperature
characteristics, but the diode was sensitive to vibration.
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In the latter part of 1944, more interest was shown in the development
of electronic regulators because of a trend toward the use of enginedriven
alternators that were too large for control by carbon-pile regulators
unless separate exciter generators were used. The ATSC Equipment
Division at Wright Field sponsored the development of two regulators
to control and excite engine-driven alternators rated 8 kva, l-phase,
400 to 800 cps, 115 volts a-c. One developed by Bell Laboratories
weighed 33 lb; its operation was reported to be very satisfactory.
In 1945 Radiation Laboratory undertook the development of regulators
using a saturated-diode voltage-sensitive element and gridcontrolled
thyratrons in the output. The intention was to perfect a
more or less universal regulator which could be applied to different
alternators by changing the thyratron output. The development had
progressed to the preliminary test model stage for two types; one type
for single-phase inverters which had been applied to the PU-7 2.5-kva
machine, and one type for 3-phase engine-driven alternators of 6.5- to
12-kva rating. The results were very promising, and it appears quite