Maintenance
performed by voltage regulators and their auxiliary
equipment is to keep the generator terminal voltage
Voltage regulator systems on board gas
within specified limits. The voltage regulator also
turbine-powered ships are maintained by PMS.
provides for proper division of the reactive current
Remember to refer to the appropriate manufacturer's
between generators operating in parallel.
technical manuals for detailed instructions concerning
If you consider all the possible combinations of
t h e maintenance of voltage regulators. You can,
types of voltage-sensitive elements and their associated
h o w e v e r , use the following general instructions
control means, you can visualize why there are so many
whenever you are performing maintenance on any
different types of voltage regulators. The two types used
voltage regulator:
specifically on gas turbine-powered ships are the
1. Make sure all connections to the
static exciter and electronic voltage regulator,
v o l t a g e - s e n s i t i v e element and those between the
and the
element and all the auxiliary equipment are tight. These
connections should be exactly as specified in the
rotating brushless ac exciter with electronic
manufacturer's wiring diagram.
voltage regulator.
2. Make all necessary adjustments according to the
We will briefly discuss each of these types.
manufacturer's technical manual.
Static Exciter Voltage Regulator
3. Make sure all contacts are clean and free from
grease, dirt, or other foreign material.
The static exciter voltage regulator system supplies
4. Make sure all brushes, relays, contractors,
dc current to the ac generator field by rectifying a part
damping devices, and motor-operated potentiometers
of the ac generator output. The voltage detector consists
move freely and smoothly. Make sure these components
of a network of capacitors, reactors, and resistors. It
are unobstructed by any foreign material.
controls the power input to the generator field by
magnetic amplifiers or silicon controlled rectifiers
5. See that the connections to the contacts of the
(SCRs).
voltage-sensitive element and relays give the correct
direction of rotation to the pilot motor of the field
This type of voltage regulator system is found on
rheostat.
the DD-963, DDG-993, and FFG-7 class ships. The
voltage regulator on the DD-963 and DDG-993 class
6. Make sure the contact arm of the motor-operated
ships is located in the generator control unit (GCU) for
field rheostat moves smoothly over its entire range. This
the associated generator. The GCU is mounted near each
movement should be at the same speed up and down,
associated switchboard. The voltage regulators on the
when driven by the pilot motor or when operated by
FFG-7 class ships are located in cabinets in the auxiliary
hand.
machinery rooms (AMRs) and in the switch gear room.
7. Check the limit switches to see that they function
properly to disconnect the pilot motor from the line
Brushless AC Exciter Voltage Regulator
when they are tripped by the contact arm.
8. Make sure the pilot motor is clean and free from
The brushless ac exciter voltage regulator system
cracks, chips, and obstructions. Check the motor for
controls the dc power delivered to the stationary field of
signs of overheating.
a brushless exciter. Its rotating armature ac output is
rectified by SCRs mounted on or in its shaft. The
regulated dc power is connected directly to the main
Troubleshooting
generator field. This statically controlled rotating
system is brushless, having no commutators or slip
rings. Because of this design, measurement of main
When troubles develop in voltage regulators, you
generator field voltage and current is not practical.
must locate the faulty component, remove it, and replace
it with a new one. Once again, you should use the
This type of voltage regulator is found on the CG-47
manufacturer's technical manual to isolate the troubles.
class ship and is located in the GCU mounted near each
Remember, you should consider the common
associated switchboard. The voltage regulator on the
malfunctions we will discuss in the next paragraph as
DDG-51 class ship is located in the exciter control panel
(EXCOP).
supplemental information to the specified malfunctions
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