TM 55-1930-209-14&P-9-1
C-2.
Major components. The Electrical Power Systems consists of the Normal Electrical System, the Emergency
Electrical System, the 155 kW Ship Service Generators and the 20 kW Ship Auxiliary Generator Set.
C-3.
System description.
C-3.1
Normal electrical system description. The normal electrical system provides electrical power for the operation
of major auxiliary systems on the barge including the emergency system battery charger.
Normal electrical power is generated onboard by one of three diesel-powered generator sets. These generators,
located in voids 4, are normally operated and controlled from a master switchboard in the ROWPU space. When all
generator sets are shut down, a shore-based powerplant or another vessel can be used to provide electrical power to
operate onboard equipment. This outside source is connected to the barge through electrical cabling to a watertight shore
power receptacle on aft weatherdeck portside. These sources provide 440 Vac, 60 Hz, 3 ph electrical power.
Power control and distribution is provided by a main switchboard on the port bulkhead aft of diesel high pressure
(HP) pumps in the ROWPU space. This unit has six panels, three above the grab rail and three below. The three panels
above the grab rail are controls and indicators for the three diesel generators in voids 4. The lower left (as operator faces
the switchboard) distribution panel has two rows of circuit breakers that provide initial normal power distribution. Two
lower right panels contain controls and indicators for the electrical systems. This panel also has indicators for ground
detection system.
C-3.2
Emergency electrical system. The emergency electrical system provides a limited amount of 120 Vac and 24
Vdc power for selected essential lighting and power requirements. This system’s central unit is a battery bank on the
deckhouse top that is maintained at full charge by a battery charger in the workshop. The charger receives its power from
the normal electrical system. When normal power is disrupted, the battery bank provides24 Vdc to an inverter. The
inverter converts this power to 120 Vac, which is supplied to the 120 Vac emergency lighting panel. In addition, this
battery bank provides continuous 24 Vdc power directly to a DC power panel. This system automatically provides 120 Vac
power for emergency lighting in the ROWPU space and voids and 24 Vdc power for direct current equipment.
C-3.3
155 kW ship service generators. Two diesel powered generator sets, each rated at 155 kW, serve as primary
electrical power sources for the barge. When shore power is not used, one SSG must be online when any of the ROWPU
major systems are being operated. These SSG’s, number 1 in void 4 port and number 2 in void 4 starboard, are
Caterpillar diesel engine driven generator sets. Each SSG consists of a Caterpillar 3306TA diesel engine and a Caterpillar
Model SR4 generator mounted, with isolation isolators, on a common base. The set weighs 3960 pounds dry and 4180
pounds wet and is 118 inches long, 39 inches wide, and 59 inches high. The third generator set, rated at 20 kW, supplies
power for the barge when ROWPU major systems are not operating and there is a lower demand for electrical power.
C-3A
20 kW service auxiliary generator. The 20 kW SAG set supplies limited amounts of electrical power for the
barge when ROWPU systems are not in operation. It provides sufficient power for operating normal lighting, dayroom
equipment, workshop equipment, and battery chargers. It must never be used to provide power for any major system
onboard.
This generator set consists of a Perkins Model 4.236M engine and a Newage Stamford SC144E generator mounted, with
vibration isolators, on a common base. It has free standard switching gear and is capable of parallel operations. The set
weighs 1300 pounds dry and 1451 pounds wet and is 74 inches long, 26 inches wide, and 40 inches high.
C-3
