separation of sections provides greater protection from
Testing
damage since it is less likely that more than one unit can
be damaged by one hit in battle. It also provides a means
When testing any ABT, make sure any vital or
for removing a damaged section for repairs or
sensitive loads fed from the ABT are isolated. This
replacement.
momentary interruption of power could damage
sensitive electronic circuitry. Therefore, before
Switchboards provide three distinct functions
beginning testing an ABT, you must notify all
aboard ship:
personnel concerned of the power supply system
1. The distribution of 450-volt, three-phase, 60Hz
interruptions.
power throughout the ship
SHIP'S SERVICE
2. The protection of distribution circuits
SWITCHBOARDS
3. The control, monitoring, and protection of the
gas turbine generator sets (GTGSs)
Aboard modem Navy vessels, there are three
distinct groups or shipsets of distribution switchboards.
A shipset of main power distribution switchboards
Capabilities
consists of three groups, each group being made up of
three units. Figures 3-6 through 3-8 show the
Each switchboard group is an operationally
switchboards making up shipset 1S.
independent system, capable of monitoring and
controlling an associated generator. Because it is
The units, physically separated and connected by
operated as an independent system, a switchboard is
cables, form a switchgear group. The physical
capable of distributing the power produced by the
Figure 3-7.--1SA Ship's service switchboard.
Figure 3-6.--1S Ship's service switchboard.
3-6
