CHAPTER 3 EMERGENCY ELECTRICAL SYSTEM
SECTION I. Description and data
The emergency electrical system provides a limited amount of 120 Vac and 24 Vdc power for selected essential
lighting and power requirements.
This systems 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 provides 24 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.
Components of this system are listed in Table 3-1 and shown in drawings referenced in Appendix A. Schematic of
the systems operations is shown in Figure 3-1.
Capabilities. This system automatically provides 120 Vac power for emergency lighting in the ROWPU
space and voids and 24 Vdc power for direct current equipment.
Special limitations. The battery bank, under optimum conditions, provides only 305 ampere hours of electrical
power. This equates to about 5 hours of operating lights and equipment connected to the 120 Vac emergency lighting panel
and/or very limited use of equipment powered from the 24 Vdc power panel.
b. Inverter power
Number of banks
Ampere hour per bank
Total ampere hours