3-12.2 Emergency operations. When normal electrical sources fail (or when circuit breaker 10P13 is open), holding
voltage on output side of inverter drops out. Inverter becomes active with 24 Vdc coming from battery bank and 120 Vac
going to emergency lighting panel. This panel provides power to fluorescent lights in deckhouse and voids, marine radio,
and telephone station buzzers. Battery bank continues to supply 24 Vdc electricity to DC panel in workshop for operating
circuits listed in previous paragraph. If battery bank is at full charge, it provides emergency electricity, depending upon
power load, for about 5 hours.
3-12.3 Restoration of normal source of electricity. When normal power is restored, 120 Vac electricity flows to output
side of inverter. Inverter ceases to operate, and 120 Vac, from normal power source, provides power directly to
emergency lighting panel. The 120 Vac also flows to battery charger, which recharges battery bank Battery bank
continues to provide 24 Vdc to DC power panel.
Section IV. Operating instructions
3-13 Operating controls and Indicators.
The 24 Vdc power panel in workshop contains eight circuit breakers and one fused circuit (Figure 3-18).
Emergency lighting panel, in ROWPU space on forward bulkhead, contains eight circuit breakers (Figure 3-19).
Battery charger in workshop (Figure 3-20) has HIGH/FLOAT switch on panel. HIGH setting activates fast
charging circuit in charger. FLOAT setting activates slower charging circuit than HIGH setting and maintains
charge in battery at all times. FLOAT is normal setting. When activating system after a shutdown of more than 3
days, set on HIGH for not more than 24 hours.
Battery charger panel displays a DC ammeter and DC voltmeter(Figure 3-20) that indicate charging rate and
Battery charger panel has ON/OFF switch that turns charger on or off.
Battery charger panel has RESET button. When pressed, it resets internal circuit breakers on AC input and DC
output circuits. Prior to resetting, troubleshoot emergency system to determine why circuit breakers were tripped.
Inverter in workshop has ON/OFF switch that turns inverter on or off.
3-13.1 Prestart checks. Before energizing emergency electrical system, perform the following before operation
preventive maintenance services:
Fumes from batteries may be flammable and explosive. Do NOT smoke or have
open flame when checking or working on battery bank.
Check batteries (Figure 3-21) for proper electrolyte level. Add distilled water or dean water to bring level above
Battery electrolyte presents potential health hazards. Contact with eyes and skin
should be avoided. Safety glasses, gloves, and rubber aprons must be worn when
handling this chemical. Electrolyte contains sulfuric acid, which can cause severe
bums, and is highly toxic to skin, eyes, and respiratory system.