NOTE: Perform Step 7 only if the set is not
The engine may require the use of a cold weather
being paralleled with an existing power source.
starting aid if the ambient temperature is below 40°F
If the set is being paralled with a power source
(4°C). Refer to Cold Weather Starting Aids.
a l r e a d y on the line, r e a d and follow the
instructions under Paralleling before turning
Press the throttle button (15) and turn the throttle
the circuit breaker control to the on position.
control (16), Fig. 1, counterclockwise to a position
midway between run and stop. Then press the starter
button (18) firmly.
If the engine fails to start within 30 seconds, release
If the load conditions require an additional set to be
the starter button and allow the starting motor to cool
placed on the line, the following instructions will apply
a few minutes before trying again. If the engine fails
to power generator sets of equal capacily, with one set
to start after four attempts, an inspection should be
in operation on the line.
made to determine the cause.
1. Prepare the set to be paralleled as outlined under
P r e p a r a t i o n for Starring, Starring, Running and
CAUTION: To prevent serious damage to the
Items 1 through 6 under Preparing Generatorfor Load.
starter if the engine does not start, do not press
the starter switch again while the starter motor
2. Check the voltmeter (12), Fig. 1; the voltage must
be the same as the line voltage. Adjust the voltage
regulator rheostat control (4) if the voltages are not
If the oil pressure is observed to be normal, increase
3. Place the synchronizing lamp switch (6) of the
the throttle setting to cause the engine to run at its
generator set to be paralleled, in the on position.
4. Turn the vernier throttle knob (17) until both sets
are operating at approximately the same frequency,
PREPARING GENERATOR FOR LOAD
indicated by the slow change in the brilliancy of the
After the engine has warmed up (or the oil pressure
has stabilized), prepare the generator set for load as
5. When the synchronizing lamps glow and then go
out at a very slow rate, time the dark interval. Then, in
the middle of this interval turn the circuit breaker
1 Bring the engine up to rated speed. Then place the
control to the on position. This places the incoming set
field switch (7) Fig. 1, in the on position.
on the line, with no load. The proper share of the
existing load must now be placed on this set.
2. Turn the voltage regulator switch (3) on.
6. The division of the kilowatt load between the
3. Turn the instrument selector switch (9) to the
alternating current generators operating in parallel
depends on the power supplied by the engines to the
generators as controlled by the engine governors and
4. Turn the field rheostat (8) slowly in a counterclock-
is practically independent of the generator excitation.
wise direction to raise the voltage, while watching the
Divide the kilowatt load between the sets by turning
voltmeter, until the rheostat reaches the end of its
the vernier throttle knob (17) counterclockwise on the
travel. The voltage regulator will take control of the
incoming set and clockwise on the set that has been
generator voltage as the field rheostat reaches the end
carrying the load (to keep the frequency of the sets
of its travel.
constant) until both kilowatt meters indicate that each
set is carrying its proper percentage of the total K.W.
5. If the power generator unit is equipped with a
load. Refer to Item 8 if the sets are not equipped with
frequency meter, adjust the engine speed with the
vernier throttle knob (17) until the desired frequency
is indicated on the meter.
7. The division of the reactive KVA load depends on
the generator excitation as controlled by the voltage
6. Adjust the voltage regulator rheostat (4) to obtain
regulator. Divide the reactive load between the sets by
the desired voltage.
turning the voltage regulator rheostat control on the
incoming set (generally counterclockwise to raise the
7. Make sure all power lines are clear of personnel,
voltage) until the ammeters read the same on both sets
then place the circuit breaker control (10) in the on
and the sum of the readings is minimum.