Western Electric 407A-4, Инструкция по эксплуатации

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Miscel laneous Circuits
Transformer T2F supplies 24 volts for the overload
lamps . One-half of the secondary winding als o furnishes 12
volts for the window latches through an auxiliary contact on
the safety switch of the high-voltage rectifier tube unit .
The other half of the winding supplies 1 2 volts for the
alarm bell BLIF through the contacts of the water thermometer
TDlF.
Water-Cooling System 6 )
General
The distilled-water cool ing system of the 407A-4 Radi o
Transmitt ing Equipment is designe d to maintain the tempera­
ture of the water-cooled vacuum tubes within safe limits .
The system is s imple in principle ; as shown diagrammatically
on Figure 6, it cons ists of a water reservo ir , a pump which
draws water from the reservoir and for ce s the water thr ough
the vacuum tube cool ing j ackets , and a cooler through which
the water pas ses from the vacuum tub es back to the water
res ervoir .
B ecaus e the vacuum-tube cool ing jackets are at high
potentials , it i s necessary t o insulate them effectively
from ground. This insulation is provided ins ofar as the
water-cooling system is concerne d by long lengths of ceramic
tubing leading the water to and from the tube jackets . This
tubing provides very effective insulation as long as the
dis ti lle d water remains uncontaminated. It i s , therefore,
extremely important that any loos e dirt or solder flux be
completely flushed out of the system before operation of
the tubes is attempted, and that nothing but high-grade dis ­
ti lled water be used for regular servic e .
A cons tant check i s kept on the effectivene ss o f the
insulati on of the water and water connections by the leak-
2 9