4. Turn the vernier throttle knob until both units are
that unit reads approximately 40 per cent of the total
operating at approximately the same frequency as
indicated by the slow change in the brilliancy of the
9. Rotate the voltage regulator rheostat control on the
incoming generator clockwise to raise the voltage until
5. When the synchronizing lamps glow and then go out
the ammeters read the same on both units.
at a very slow rate, time the dark interval. Then, in the
middle of this interval, turn the circuit breaker control to
NOTE: If a load was not added during
the on position. This places the incoming generator set
paralleling, the total of the two ammeter
on the line, with no load. The proper share of the
readings should be the same as the reading
existing load must now be placed on this generator.
Readjust the voltage
regulator rheostat on the incoming
6. The division of the kilowatt load between the
generator, if necessary.
alternating current generators operating in parallel
depends on the power supplied by the engines to the
10. To reset the load voltage, turn the voltage regulator
generators as controlled by the engine governors and is
rheostat controls slowly on each unit. It is necessary to
practically independent of the generator excitation.
turn the controls the same amount and in the same
Divide the kilowatt load between the generators by
direction to keep the reactive current equally divided.
turning the vernier throttle knob counterclockwise on the
incoming generator and clockwise on the generator that
Power generator sets with different capacities can also
has been carrying the load (to keep the frequency of the
be paralleled by dividing the load proportionately to their
generators constant) until both ammeters read the
same, indicating that each generator is carrying its
proper percentage of the total K.W. load.
7. The division of the reactive KVA load depends on the
The procedure for stopping a power generator set or
generator excitation as controlled by the voltage
taking it out of parallel is as follows:
Divide the reactive load between the
generators by turning the voltage regulator rheostat
1. Turn off all of the load on the generator when
control on the incoming generator (generally clockwise
stopping a single engine unit.
to raise the voltage) until the ammeters read the same
on both generator sets and the sum of the readings is
2. Shift the load from the generator when taking it out of
parallel operation by turning the vernier throttle knob
until the ammeter reads approximately zero.
NOTE: The generator sets are equipped with
3. Place the circuit breaker control in the of position.
in series with the voltage coil of the
4. Turn the voltage regulator rheostat control in a
which equalizes most but not all of the
counterclockwise direction to the limit of its travel.
reactive KVA load between the generators.
5. Press the throttle button and turn the throttle control
8. When the load is 80 per cent power factor lagging
to stop to shut-down the engine.
(motor and a few lights only), turn the vernier throttle
knob on the incoming generator until the ammeter on
NOTE: When performing a tune-up on a
generator set that will be operated in parallel
with another unit, adjust the speed droop as
specified in Engine Tune-Up.