MIL-DTL-16036M(SH)
3.4.1.9 Load shedding. Distribution units of ship s service switchgear groups on ships provided with a
centralized machinery control system including an EPCP or an EPCC, or both an EPCP and an EPCC, for which
load shedding is required, shall contain a load shedding bus or buses segregated from the main bus by electrically-
operated nonautomatic circuit breakers. Individual electrically-operated ship s service distribution circuit breakers
shall also be operated by the load shedding system as specified. Each electrically-operated ship s service
distribution circuit breaker not disconnected from the main bus by the load shedding system shall be provided with
means for remote control from the EPCC or the EPCP. Relays energized from EPCC or the EPCP power shall be
provided to activate the trip circuit of electrically-operated distribution circuit breakers. Shunt trip circuit of
manually operated distribution circuit breakers shall be energized from EPCC or the EPCP power. The power
sensing relay shall be in accordance with MIL-R-24563 or MIL-M-24350.
3.4.2 Emergency power switchgear groups for ships having AC power. Switchgear groups for controlling
larger than 100 kilowatt generators shall employ a three-way Type ABT-4A (9) circuit breaker type bus transfer
equipment and shall be constructed as sectionalized switchgear groups having a separate generator and bus transfer
section, and feeder sections. For switchboards controlling emergency generators rated 100 kilowatt and less, the bus
transfer equipment, Type ABT-4A (9) contactor type shall be used. When the contactor type unit is used, the
switchboard shall be assembled with the AQB distribution units to form a single section (see figure 5 and figure 6).
Bus transfer equipment shall be in accordance with MIL-PRF-17773.
3.4.2.1 AC emergency generator control and circuit breaker type bus transfer section. The following shall be
mounted on or within the unit:
a. One Type ABT-4A (9) circuit breaker type, three-way, automatic bus transfer equipment having a current
rating not less than the continuous rating of the emergency generator and the current rating of the feeders from the
ship s service switchboards, as specified. Associated control switches, indicator lights, and relays for panel
mounting shall be mounted on one of the front panels.
b. Necessary disconnecting devices for disconnecting cables between switchgear sections and performing
other isolation functions.
c.
Two potential transformers for metering and relaying.
d. One Type AQB-A or AQB-LF circuit breaker, instantaneous element only, for power supply to the pump
supplying cooling (salt) water to the generator diesel as specified (see 6.2) connected to the generator side of the
generator circuit breaker. A red warning plate shall be provided stating that the circuit breaker shall alwa ys be in the
closed position when the diesel is set up for starting.
e.
Two current transformers for metering and relaying.
f. One dead-front fuse panel for fusing the potential transformer primary circuits. Dead-front fuseholders
shall be of the type listed in 3.14.2.1 in accordance with MIL-PRF-19207.
g. One circuit breaker Type AQB-A or AQB-LF, 250-ampere frame size. Casualty power circuit breaker shall
be connected to the generator side of the generator circuit breaker. When the generator capacity is 500 kilowatts or
greater, two casualty power circuit breakers shall be furnished.
h. One casualty power terminal, back-connected type conforming to MIL-DTL-24552 and
MIL-DTL-24552/2, connected through the AQB-A or AQB-LF circuit breaker, item (g). When the generator
capacity is 500 kilowatts or greater, casualty power terminals, back-connected type, shall be furnished.
3.4.2.1.1 Front panel. The following shall be mounted on the front of the panel:
a.
One AC ammeter for reading one phase of generator current.
b.
One AC voltmeter for reading one phase of generator potential.
c.
One polyphase wattmeter for reading generator output.
d.
One frequency meter for reading generator frequency.
e. Instruction plates containing complete operating instructions for the automatic equipment and a single line
diagram of the main buses.
f. One set of three ground indicator lights (clear) with test switch to indicate ground conditions on the 450-
volt emergency power bus.
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