Western Electric 407A-4, Инструкция по эксплуатации

Страница: 79 / 136

the overload lamps .
5-kw
The cut-back to 5-kw is effected as fol lows :
( 1)
Open "H. V. Rectifier" switch D4F . This o pens pl ate
circuit breaker CB6 5P, removing the 460 volt supply
from Unit H, and taking the transmitter off the air .
(2)
Clo se the 50-kw rectifier grounding switch DlH.
This removes the 46 0 vo lt supply from Unit K, and
grounds the high voltage cir cuits of Unit H . Enter
the 50-kw enclosure .
( 3 ) Close the 5-kw rectifier grounding switch DlG
(
if
open
)
. This grounds the h igh-voltage ci�cuits of
Unit G. Enter the 5-kw encl osur e .
(
4
)
Operate the fo l lowing switche s , the c omplete func­
tions of which are repeated below :
(
a
)
D5G, a DPST switch located in the 5-kw encl osure,
which when clos ed applies full voltage to the
filaments of the 5-kw rectifier. These fila­
ments are heated at half voltage at al l times
during 50-kw operat ion.
(
b
)
D6G, a 4PDT switch located in the 5-kw enclosure
which s ets up the c ontrol cir cuits for either
50-kw or 5-kw operation. Operati on of this
switch energizes one or the other of each of
s everal pairs of c ontactors which complete the
control, power-supply, b ias , and radio -frequency
circuits as required for either oper ating con­
dition.
These c ontactors and their functi ons are as
follows :
72