TM 55-1905-223-24-14
(3) Power Converter. The power converter is located in the pilot house, as shown in FIGURE 1-3. The power
converter (FIGURE 1-7) adapts the gyro compass equipment to the ship's single phase 120 Vac, 60 Hz power source.
The converter is housed in a watertight enclosure and is bulkhead mounted. The cover contains a lamp holder and fuse
holder. Two stuffing tube assemblies are affixed to the enclosure on either end, for power cable attachment. The unit
converts the ship's ac input power to 24 Vdc for use by the gyro compass equipment and provides 120 Vac, 60 Hz power
to the gyro control and power assembly.
(4) Switch Unit. The switch unit is located in the pilot house, as shown in FIGURE 1-3. The switch unit
(FIGURE 1-8) is contained in a drip-proof enclosure with a cover secured with fasteners and attached to the enclosure
with a chain. Three stuffing tubes are affixed to the underside of the enclosure for cable access. The unit is bulkhead
mounted with four bolts. The switch unit controls the power delivered to the coils of two remote steering repeaters and
will drive two 70 Vdc step motors. The switch unit is a component of the gyro compass system transmission circuit.
(5) Relay Transmitter. The relay transmitter is located as shown in FIGURE 1-3. The relay transmitter (FIGURE
1-9, Sheet 1) is a MK 37 Mod E type transmission unit. The unit consists of a drip-proof enclosure which contains two
subassemblies: repeater circuit card assembly A1 and transmission terminal circuit board A2. Front cover and chassis
mounted components are used for input power regulation, protection, and control circuits. The unit operates from ship's
ac power. Terminal board connections match input power to an internal transformer for different ac input power. The
main power switch, power fuse F1, and power indicator lampholder are mounted on the front of the hinged cabinet cover.
Switches and fuses for each transmission output channel are located inside the enclosure on transmission terminal circuit
board A2 (FIGURE 1-9, Sheet 3).
(a) Repeater Circuit Card Assembly A1. The repeater circuit card assembly A1 (FIGURE 1-9, Sheet 2) is
mounted on the rear of the enclosure cover. This assembly amplifies the signal from the step transmitter (in the gyro
compass) to provide enough power to drive up to 12 repeaters with 70 Vdc coils. This assembly also converts the ship's
ac input to 70 Vdc output for the repeaters.
(b) Transmission Terminal Circuit Board A2. The transmission terminal circuit board A2 is mounted in the
rear of the enclosure (FIGURE 1-9, Sheet 3). The board contains 12 identical output control and switch circuits. Each
circuit contains an On/Off toggle switch and a series fuse.
(6) Power Transfer Unit. The power transfer unit is located as shown in FIGURE 1-3. The power transfer unit
(FIGURE 1-10) is bulkhead mounted with four bolts. The unit is housed in a drip-proof electrical equipment cabinet. Two
stuffing tube assemblies are affixed to the underside for cable access. The unit contains no external controls. Four
thumbscrews on the cover allow for cover opening for access to the inside. The power transfer unit transfers the gyro
compass equipment from normal input dc power from the power converter to the ship's emergency dc supply in the event
of normal supply failure.
1-9
Previous Page
