The second designation will tell you the voltage
parts are (1) the core, which provides a circuit of
potential and the use of the power. The most
low reluctance for the magnetic flux; (2) the
common voltages used are 115 volts, designated
primary winding, which receives the energy from
by a number 1, and 450 volts, designated by
the ac source; (3) the secondary winding, which
number 4. The number is actually the range the
receives the energy by mutual induction from the
voltage falls into, such as follows:
primary and delivers it to the load; and (4) the
enclosure.
When a transformer is used to step up the volt-
VOLTAGE RANGE
DESIGNATOR
age, the low-voltage winding is the primary. Con-
versely, when a transformer is used to step down
100 to 199
1
the voltage, the high-voltage winding is the pri-
mary. The primary is always connected to the
200 to 299
2
source of the power; the secondary is always con-
nected to the load. It is common practice to refer
300 to 399
3
to the windings as the primary and secondary
rather than the high-voltage and low-voltage wind-
4
400 to 499
ings. For more information on the construction
and installation of transformers, refer to the Elec-
The letter part of the designation shows the use
trician's Mate, NAVEDTRA 12164.
of the power. The most common ones are as
follows:
POWER PANELS AND
CABLE MARKINGS
FEEDER
DESIGNATOR
Some method must be used to locate power
panels and the equipment that is fed. Also, switch-
K
Control, power plant, and ship
boards must have markings on the breakers to
identify what circuits or equipment are fed. The
Interior communications
C
Navy uses a standard system to identify the
location and source of power for all switchboards,
Emergency lighting
EL
panels, and loads. This system uses the
deck/frame/side location that identifies other
L
Lighting
shipboard components. The system is also used
on cables to identify their power source.
CP
Casualty power
The first part of the designation you see
identifies the switchboard or load center that
supplies the power. This could be numbers or a
Ship's service power
P
letter/number combination. The following is an
example of some markings you may find and what
WP
Weapon's power
the first number means.
Other letters and symbols are used with these
1SB-4P-2-216-2-C
basic letters to form the complete cable designa-
tion. This gives the cable's source, service, and
From #1
designation. Typical markings for power system
SWBD B section
cables from a generator to a load and the
meanings of the symbols are as follows:
41-4P-216-C
1. Generator cables: 2SG-4P-2S
From load
center 41
2SG--Fed from ship's service (SS)
generator No. 2
3SA-4P-42
4P--450-volt power cable
From #3
2S--Supplying SS switchgear group No. 2
SWBD A section
9-19