TM 55-1905-223-24-14
Section II. EQUIPMENT DESCRIPTION AND DATA
1-6. Gyro Compass.
a. Equipment Characteristics, Capabilities, and Features. These are very broad points about the Gyro
Compass System.
(1) Characteristics:
o
Gyro compass can give true north.
o
Gyro compass electronics compensate for earth's magnetic fields.
o
Gyro compass is an electric compass.
o
Ship's emergency power source provides 24 Vdc backup capability.
(2) Capabilities and features:
o Gyro compass transmits the ship's heading to external repeaters.
b. Location And Description Of Major Components. The basic MK 27 Mod 1 Gyro Compass System consists of
the gyro compass, gyro control and power assembly, power converter, and switch unit. In addition to the basic
equipment, the system also utilizes a power transfer unit, a relay transmitter (MK 37 Mod E transmission unit), three
bearing repeaters mounted in pelorus stands, two open scale repeaters mounted in bulkhead mounting brackets, a
standard Navy type azimuth circle, and three bearing repeater covers to be placed over the bearing repeaters to protect
the repeaters when not in use. Ship's cabling connects the system. The major components of the system are illustrated
(1) Gyro Compass. The gyro compass is located in the pilothouse, FIGURES 1-3 and 1-4. The gyro
compass (FIGURE 1-5) consists of a shock-mounted, fluid-filled binnacle which houses the gyroscope (sensitive
element). The unit is sealed and is mounted on top of the gyro control and power assembly. The gyroscope can be
caged (suspended from operation) by pressing a button on the top of the unit to prevent damage when not in use. The
viewing window for the compass card is on the aft end of the compass. The dial is red lighted and its brightness is
adjusted at the gyro control and power assembly.
(2) Gyro Control and Power Assembly. The gyro control and power assembly is located in the pilot
which houses the control panel, power supply, servoamplifier, latitude compensation circuit, and alarm circuit. Power
amplifier transistors are attached to the cabinet frame for adequate heat dissipation. The unit is mounted directly under
the gyro compass to permit ease of operation when starting or adjusting dial illumination.
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