Fine And Course Voltage Adjust; Under Frequency Adjust; Current Limit Adjust; Field Set Up Procedure - Generac Power Systems APS 6.0 Operating & Installation Manual

Figure 3.6 — Voltage Regulator Set Up
The voltage regulator will be set at the factory to pro-
vide the required output voltage. However, should
adjustment be required in the field, the regulator is
fitted with four adjustment potentiometers (Figure
3.7).
Figure 3.7 — Field Adjustment Points
Unnecessary adjustment of these potentiometers
by inexperienced personnel will result in the
impairment of the unit performance. Do not adjust
any pot without clear knowledge of its affect on
the generator.

3.4.2 FINE AND COURSE VOLTAGE ADJUST

These two potentiometers set the required output
voltage.

3.4.3 UNDER FREQUENCY ADJUST

This potentiometer allows the frequency at which the
voltage beings to drop off to be varied. This is one of
the devices built into this generator to protect the
engine from overload and potentially a burnout. If the
engine for some reason begins to overload, it will
slow down. Rather than the voltage regulator increas-
ing the excitation current at a set frequency (to main-
tain constant output voltage), the voltage regulator
will begin to lower the output voltage while maintain-
ing near constant speed (decreasing engine load).
10 Generac ® Power Systems, Inc.
Section 3 — Operation
Generac APS 6.0 DC Auxiliary Power System
NOTE:

3.4.4 CURRENT LIMIT ADJUST

Another protection device built into the generator is
that the potentiometer allows a maximum current
limit to be set. This is because the generator will be
connected to a bank of batteries. In a state of dis-
charge, the batteries will demand high charge cur-
rents far in excess of the rating of the generator. To
prevent overload, the output current is monitored via
a current transformer. The potentiometer has been
factory set for the output voltage to begin to drop off
at approximately 225 Amps DC in an attempt to
maintain a constant output current.

3.4.5 FIELD SET UP PROCEDURE

The following is the recommended procedure for
checking the output voltage on the generator. This
procedure should be performed after the unit has
been installed on site but BEFORE the unit is con-
nected to the Lucent Technologies Rectifier cabinet.
The voltage set point should be 26.2 VDC.
1. Attach two 12 volt automotive type batteries, con-
nected in series (to provide a 24V supply), to the
output terminals of the generator.
2. Attach a digital voltmeter to the output terminals
of the generator.
3. The voltmeter should be reading approximately
25V. If the batteries are fully charged, and the
voltmeter reads above 26.2V, then it will be nec-
essary to discharge the batteries. When a voltage
between 25V to 25.5V has been achieved, contin-
ue the setup.
4. Start the unit in the manual mode. The engine
will start and stabilize. After a delay of between
15 to 45 seconds, the voltage regulator will turn
on. This will be apparent in a sudden engine
sound change, and the voltmeter will be reading a
higher voltage than previously. This voltage is fac-
tory set at 26.2V. Confirm this, and if the voltage
is correct, shut the unit down and continue the
installation. If the voltage set point is low or high,
proceed as follows.
5. Using a combination of both the fine and coarse
voltage adjust potentiometers, readjust the out-
put voltage to 26.2V. Use caution during the
adjustment as the coarse potentiometer is very
sensitive and a small change will result in a
large voltage change.
6. If for some reason the voltage is mistakenly
turned too low and the voltmeter is again reading
battery voltage, slowly turn the voltage pots up
until the change in engine sound is heard.
Continue to adjust the voltage as described
above.