Central Control Station Local IC Switchboard

SWITCHBOARD MAINTENANCE

Central Control Station Local IC Switchboard

Another of your duties as an IC Electrician is the

On ships with a central control station, a local IC

maintenance of the power distribution systems

switchboard is provided to energize the machinery

assigned to your division. Normally, the required

control IC systems.

inspections and cleaning are outlined on maintenance

The central control station switchboard receives

requirement cards (MRCs). When the inspection and

its normal power supply (120-volt, 60-Hz, 3-phase)

cleaning is due, you often think only of the main IC

from one of the ship's power panels. One of the ship's

switchboard. The small local IC switchboards located

lighting panels provides the emergency supply. The

in the engineering spaces and the remote sections of

switchboard also includes an ABT device, power

the ship are often forgotten. Auxiliary IC panels may

available indicator lights, and supply switches for the

have their own MRCs.

various machinery control systems.

Switchboard preventive maintenance will be

accomplished according to the applicable MRCs.

Steering Gear Room Local IC Switchboard

Corrective maintenance and troubleshooting will

usually consist of clearing grounds, repairing open

A local IC switchboard is usually installed in each

circuits, tightening loose connections, and finding the

steering gear room to energize all circuits associated

cause for blown fuses and overloads.

with steering-order and rudder-angle indicator

systems.

INSPECTION AND CLEANING

The switchboard receives its 120-volt, 60-Hz,

Loose electrical connections or mechanical

s i n g l e - o r 3-phase normal input from the

fastenings have caused numerous derangements of

steering-power transfer switchboard or one of the

electrical equipment. Loose connections can be

ship's power panels located in the steering gear room.

readily tightened, but it requires thorough inspection

A local emergency lighting circuit provides

to detect them. Consequently, at least once a year and

emergency power. This switchboard includes an ABT

during each overhaul, each switchboard, propulsion

device, power available indicator lights, supply

control cubicle, distribution panel, and motor

switches, and ACO switches.

controller should be de-energized for a thorough

inspection and cleaning of all bus equipment.

IC TEST SWITCHBOARDS

Inspection of de-energized equipment should not be

limited to visual examination but should include

Dead-front IC test switchboards are installed in

touching and shaking electrical connections and

the IC shops on most ships to provide a means of

mechanical parts to make sure that the connections are

performing operational tests and for troubleshooting

tight and mechanical parts are free to function. Where

IC components.

space permits, a torque wrench should be used when

tightening bolts. Overtightening can be detrimental as

The test switchboards are normally set up to

undertightening. Refer to NSTM, chapter 075,

provide the following test outputs:

"Threaded Fasteners," for torquing procedures and

120 volts, 60 Hz, single phase

precautions. Table 3-1 contains torque values for the

more common bolt sizes used in switchboard

0 to 230 volts, 60 Hz, single phase

construction. Torque values are minimum and should

120 volts, 400 Hz, single phase

not be exceeded by more than 10 percent.

80 volts, 20 Hz, single phase

Be certain that no loose tools or other extraneous

articles are left in or around switchboards and

120 volts dc

distribution panels. Check the supports of bus work to

0 to 120 volts dc

be certain the supports will prevent contact of bus bars

of opposite polarity, or contact between bus bars and

The test switchboard may also contain ac and dc

grounded parts during periods of mechanical shock.

voltmeters, ammeters, test jacks, test leads, lamp test

Clean the bus work and the creepage surfaces of

sockets, a multimeter, and a fuse tester. These

insulating materials, and be certain that creepage

capabilities permit comprehensive bench testing of all

distances are ample. If damaged, taped switchboard

types of IC equipment.

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