Bus Transfer Equipment -141220090

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

coil.

manual bus transfer equipment, manually transfer a load

from one power source to another and check the

Potential Transformers

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.

DIAGNOSTIC MAINTENANCE

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.

Current Transformers

ENGINEERING OFFICER OF THE

The secondary of a current transformer should

WATCH

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.

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