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 TM 55-1905-219-14-9
4-64.1. TANK LEVEL INDICATION-RECEIVER-MAINTENANCE INSTRUCTIONS
(Continued).
terminal board associated with a given control module in place of the connections that are normally made to
the fluid level detector (transmitter and/or level links). Adjustment of the FLOAT SIMULATOR there-after can
be accomplished to develop signals that simulate the different values possible for level signals.
(2) Receiver Power.
(a) The distribution of ac and dc power in a typical receiver panel is shown below. Ship's
115 volt, 60 Hz ac power is applied through FUSE, 2 AMP fuse F1 to ON-OFF switch S1. When the switch is
placed in the ON position, the ac input is connected across POWER lamp DS1 and to the primary of
transformers T1.
(b) The ac voltage at the secondary of transformer T1 is applied to full-wave bridge rectifier
CR1 thru CR4 on power supply and master alarm module PS-1. The rectified output of the bridge rectifier is
limited by resistor R1 located on the module and filtered by capacitor C1 mounted on the frame of the receiver
panel. The filtered voltage is fed to voltage regulator microcircuit chip V1 to develop a regulated +17 volt dc
output. Capacitor C1 on power supply and master alarm module PS-1 provides additional filtering for the
supply.
(c) The ac voltage-at the secondary of transformer T2 is jumpered as shown.
c.
Detailed Circuit Description.
(1)
Refer to Foldout 3 for the overall schematic.
(2)
Power Supply and Master Alarm Modules PS1.
(a) One power supply and master alarm modules are supplied with a receiver panel. As
shown below, the: module is comprised of two circuits, a power supply and master alarm circuit. The operation
of the power supply circuit elements is described in paragraph 4-64.lb(2). The operation of the master alarm
circuit is as follows:
(b) Alarm signals are applied at pin 7 of the module for application through diode CR1
across resistor R1 to the base of relay driver transistor Q1. The presence of the alarm signal, which is a
positive-going pulse produces conduction in transistor Q1. When transistor Q1 conducts, it provides a current
path from a return line at pin 8 of the module through the coils of relays K1 and K2 to the positive power supply
voltage at pin 12. Current flowing over this path energizes the two relays. When the A contacts of relay K1
close in response to the energizing of the relay, a bypass is provided around transistor Q1. This bypass serves
as a holding path for the relay
4-1333
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