SHIP’S SERVICE SWITCHBOARDS

After a sudden loss of power, having a manual transfer of the power source will ensure all conditions are met before energizing the equipment. (See figure 3-4.) AUTOMATIC BUS TRANSFER (ABT) SWITCHES ABTs are used to provide two sources of power to those loads that MUST be re-energized as soon as possible after a sudden loss of normal power. Some examples would be lighting in main engineering spaces, ship’s steering motors and controls, motor-driven fuel pumps, and lubricating oil pumps. SHIP’S SERVICE SWITCHBOARDS Aboard modem Navy vessels there are three distinct groups or shipsets of distribution switchboards. A shipset of main power distribution switchboards consists of three groups, each group being comprised of three units. Figures 3-5 to 3-7 show the switchboards that comprise shipset 1S. The units, physically separated and connected by cables, form a switchgear group. This physical separation of sections provides greater protection from damage since it is less likely more than one unit can be damaged by one hit in battle. It also provides a means for removing a damaged section for repairs or replacement. Switchboards provide three distinct functions aboard ship: Distribution of 450-volt, 3-phase, 60-Hz power Protection of distribution circuits Control, monitoring, and protection of the generator sets Figure 3-4.-A pictorial view of the A-2 ABT. 3-4