Service manual

VOLTAGE REGULATOR ADJUSTMENTS
Description
The voltage regulator is an advanced design which ensures
optimum AC alternator performance.
It is equipped with
complete protection circuitry to guard against operating
conditions that could be detrimental to the AC alternator.
This potentiometer is used to adjust output voltage. At proper
engine operating speed the output voltage should be held at
±1 % from a no-load condition to a full rated generator output
and from power factor
1.0 - 0.8 with engine drive speed vari-
ations
up to -6%.
Prior to starting the engine, turn the VOLT and STAB trim-
mers (using a mini phillips screwdriver) fully
ina counter
clockwise (Minimum) direction until you feel them hit their
stops.
Tum the
AMP and HERTZ trimmers completely clockwise
(Maximum)
in the same manner.
With the alternator running
at no-load, at normal speed, and
with
VOLT adjust at minimum, it is possible that output volt-
age will oscillate.
Slowly rotate the VOLT adjust clockwise.
The voltage output
of the alternator will increase and stabi-
lize. Increase the voltage to the desired
~alue. In this situa-
tion, only the green LED will stay lit.
stability
This potentiometer permits variation of the regulator's
response to generator load changes so
as to limit overcom- .
pensation and obtain a minimum recovery time to the normal
voltage output.
In order to adjust the regulator stability the alternator must be
running
a~ no-load and the output must be monitored.
Tum the STAB adjust slowly clockwise until the voltage
starts
to fluctuate. At this point rotate the STAB adjust coun-
terclockwise until the voltage is stable within 1 or 2 tenths
of
a volt.
.! green '-
~ yeHow L
Hertz
AmI!
Stab
Volt
VOLTAGE REGULATOR DIAGRAM
. Amp-Hertz
These two adjustments are used in conjunction with the two
protection circuits in the voltage regulator that are indicated
by the illumination
of a colored LED lights.
1. Delayed overload protection
(yellOW LED).
2. Low speed protection (red LED).
Both systems have an intervention threshold which can
be
adjusted using the respective potentiometer. Each of the two
circuits
are able to cause an adequate reduction in excitor
voltage to safeguard the excitor windings and prevent their
overheating.
The overload protection system has a delay which permits
temporary overloading
of the generator during times such as
motor start-up
or other similar load surge demands. The reg-
ulator also has a third LED (green), that
glows during gener-
ator operation to indicate correct operation
of the regulator
with the generator. . .
Setting the Overload Protection
In order to set the AMP overload protection, the alternator
must
be loaded to its full output rating. .
1. Load the alternator
to its rating, then decrease the speed of
the engine by 10.10% (54 Hertz on 60 hertz units, 45
hertz
on 50 hertz units).
2. Rotate the
AMP adjustment counterclockwise until it hits
its stop. Wait about 15-20 seconds after which the
AC out-
put
of the alternator should drop and the yellow LED light
should come on
..
3. Slowly rotate the AMP adjustment cl~kwise until the
output voltage increases to approximately
97% of the
voltage
output· at the start of the adjustment. At this point
the yellow LED light should come on.
4. Return
to nominal speed, the yellow LED will turn off
and the alternator voltage will.rise to its normal value.
Should this not happen, repeat the adjustment.
NOTE: When changing from 60 hertz to 50 hertz operation,
remove
the 60 hertz jumper bar from the regulator board.
Setting the Underspeed. Protection
NOTE: If the unit is operating at 60 Hertz ensure that the
jumper strap
is in place on the regulator board between the
two 60 Hertz terminals. In order to adjust the underspeed
setting, the alternator should
be running at no-load.
1. To adjust the underspeed (low frequency) protection circuit,
lower the engine speed
at 90% of its normal running speed
(54 hertz on 60 hertz units, 45 hertz
on 50 hertz units.
2. Rotate the Hertz adjustment counterclockwise slowly until
the alternator's
AC output voltage starts to decrease and at
the
same time the red "LED" light comes on .
3. Increase the engine speed to its normal speed (frequency).
The red "LED" light will go out and the AC voltage out-
put will return to normal.
With the above adjustments made, the regulator should func-
tion normally.
Engines & Generators
54