21
FINE VOLTAGE ADJUSTMENT
Upon start-up of the generator, the “Running” screen of the Magnum Digital
Controller (MDC) will display “SENSING” and will countdown from 45 seconds
to “0” Zero. This is a safety feature of the controller to protect the generator
from over or under voltage upon start-up.
“SENSING” is a 45 second time delay and count down process before the MDC
records the generator nominal output voltage. This nominal generator voltage
is then compared to the current set point voltage of the voltage selector switch.
If the nominal voltage recorded by the controller is greater than or lower than
the current set point voltage of the voltage selector switch setting by 10% or
more, the controller will shut the generator down automatically. The display will
read: Wrn VG1 or 2 or 3 Under/Over and/or Sd Vg1 or 2 or 3 Under/Over. This
means the controller warned (“Wrn”) or shut down (“Sd”) the unit due to an
output voltage irregularity.
The output voltage of the generator may be adjusted after the generator is running by using the fine voltage adjustment
screw. The adjusting screw is located directly below the “CONTROL ON/OFF” toggle switch on the control panel.
This screw turns a rheostat that will provide an increase (“+”) or a decrease (“-”) in the generator output voltage as
displayed on the Power Display Screen on the control panel. If the voltage is increased or decreased too fast or too
slow, the unit will automatically shut down. This adjustment needs to be made within the 45 second delay and
countdown to “0” Zero period.
To adjust the output voltage, check the output voltage on the Liquid Crystal Display (LCD) window labeled Gen freq
& Hz. Look at the L1N voltage or the L12 voltage on the display. The generator nominal output voltage should be
within 10% of the voltage rating on the voltage selector switch.
To adjust the output voltage loosen the lock nut at the base of the screw and turn the screw in the desired direction
until the required voltage shown on the LCD window matches the stated voltage on the voltage selector switch.
For Example:
With the voltage selector switch set to “208/120V” 3 Phase position, the voltage displayed on the
Gen freq & Hz screen must be within ± 10% of the 208/120 position (188-228 V Line to Line / 108-132 V Line to Neutral).
Note: Each time the voltage selector switch is changed from one setting to another, an adjustment will need to be
made to the fine voltage using this adjustment screw.
CONTROL
ON
CONTROL
OFF
VOLTAGE
ADJUSTMENT
RHEOSTAT
