accurate measurements. The secondary should always
Bus Transfer Equipment
be short-circuited when it is not connected to a current
Bus transfer equipment should be tested weekly. For
manual bus transfer equipment, manually transfer a load
from one power source to another and check the
mechanical operation and mechanical interlocks. For
automatic bus transfer equipment, check the operation
The secondary of a potential transformer should
with the control switches. The test should include
never be short-circuited. The secondary circuit should
operation initiated by cutting off power (opening a
be completed only through a high resistance, such as a
normal feeder circuit breaker) to ascertain if an
voltmeter or a potential coil circuit, or should be open
automatic transfer occurs. These tests and inspections
when the primary is energized. A short-circuited
are normally outlined on MRCs.
secondary allows excessive current to flow, which may
damage the transformer.
When you must perform electrical repair on
IC GYRO WATCHSTANDING
energized switchboards, first be sure to obtain the
As an IC1 or ICC, you will be required to set up and
approval of the commanding officer. Personnel with
train an IC gyro room watch. This training should be
telephone headsets should be stationed by circuit
tailored to the needs of your command with the
breakers to de-energize the switchboard immediately
commanding officer's authorization. This training
and call for help in case of emergency. The person doing
should be documented and conducted according to the
the work should wear rubber gloves and should not wear
requirements of the Standard Organization and
loose clothing or metal articles.
Regulations of the U.S. Navy, OPNAVINST 3120.32B.
ENGINEERING OFFICER OF THE
The secondary of a current transformer should
never be open while the primary is carrying current.
The engineering officer of the watch (EOOW) is a
Failure to observe this precaution results in possible
watch of great importance and responsibilty. We will
damage to the transformer and the generation of a
not cover it in great depth in this manual because it is
secondary voltage that may be sufficient magnitude to
covered by PQS. The EOOW requires qualification in
injure personnel or damage insulation. A current
transformer energized with an open-circuited secondary
other engineering watch areas before becoming
will overheat due to magnetic saturation of the core.
qualified in that watch station. The important thing to
Even though the overheating may have been insufficient
remember is that the EOOW is responsible for the
proper and safe operation and maintenance of all
to produce permanent damage, the transformer should
be carefully demagnetized and recalibrated to ensure
engineering equipment aboard ship.