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 TM 55-1905-220-14-1
1-49. SWITCHBOARD.
a. The Ship's Service Generating System consists of two, 3 cylinder diesel, engine-driven 450 Volt, 3-phase, 40 kw
alternating current (AC) Generators. The No. 1 Generator Set is located in the Forward Engine Room, Starboard. The
No. 2 Generator Set is in the Aft Engine Room. Both Generator Sets are controlled from one main Switchboard located
in the Engine Access Room (1-50-1-Q).
b. The Main Switchboard is able to control, protect, and permit paralleling of the two Generator Sets. Lights to protect
against circuit breaker overload and ground detection are provided on the switchboard. If needed, power can be
connected to the vessel from the shore. The Shore Power connection box is located at Frame 61 aft of the deckhouse.
The shore power box is connected to the main switchboard.
c. The switchboard is a dead-front, drip-proof bulkhead mounted type. A rear-drain type of drip shield is welded to the
enclosure top to prevent overhead dripping from interfering with the operation of the switchboard. All components are
accessible from the front after opening the front door. Cables enter the switchboard from the bottom by way of a
gasketed cable entrance plate. They are terminated inside the switchboard on stud type terminal boards or directly to
pressure terminals on circuit breakers.
d. Generator No. 1 current is shown on one ammeter. Generator No. 2 or shore power current can be selected on the
second ammeter. Voltage readings for both generators, bus and shore power, are available by use of two voltmeters and
a selector switch. Selection of individual or total wattages are available by use of two wattmeters and a switch.
Generator frequency is indicated on a single meter. A phase sequence indicator is located near the center of the
switchboard. This indicator has three neon lamps which indicate when all three phases are energized and will show
proper sequencing. When the pointer of the indicator is in the green region, it is sequencing correctly and when in the
red region sequencing incorrectly. A synchroscope is provided for the paralleling of the generators.
1-83
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