Western Electric 407A-4, Instruction Manual

Page: 14 / 136

Auxil iary (T57P ) : This is an auto­
matic regulator controlling a constant-potential a-c bus
from which all filament and b ias voltages , and the plate
voltages in the preliminary stages, are derive d.
Auxiliary Power Distribution Cabinet This
unit contains two power c ontactors supplementing thos e in
the main cabinet DP5oP.
RF
Trans fer Contactor
This contactor transfers
the outgo ing transmis s ion line between the 50- and 5-kw
radio-frequency outputs of the transmitter.
DESCRIPTION AND ADJUSTMENT OF CIRCUITS
The fol lowing des cripti on of the circu its of the radi o
transmitting equ ipment is taken up through analysis of the
complete circuit into its component parts such as the power
circuit, the control circuit, and the radio-frequency cir­
cuit . These component circuits usually extend through
several of the transmitter unit s . The identification of a
particular part of a circuit and its ass ociation with a
particular unit or group of apparatus is readily made by
the apparatus designation and by reference to the s chematic
drawings which give the ess ential internal circuits and
also the interconnect ing terminal des ignati ons . Adjustment
of the circuits and apparatus is given in s eparate s ecti ons
under each component part.
Power Circuits (Schematic
The 460-volt, 3-phas e, 60-cycle power for the opera­
tion and contro l of the transmitter is fed to the various
circu it s through the power dis tributi on cabinet (DP50P ) .
A schematic of.this unit and as s oc iated power circuits is
shown on Figure 1 . Referring to this sketch the 460-volt
s ource of supply is connected through terminals 101, 102
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