Fine Voltage Adjustment - Magnum MLT 4250 Operating & Parts Manual

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 selec-
tor 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 even 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 use of the fine voltage adjust-
ment 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. When making this adjustment, 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).
If the voltage is not set within 10% of the applied voltage or the voltage is not reset within the
45 second delay period, the generator will shut down automatically and the display will read
Wn VG1 or 2 or 3 Under/Over and/or Sd Vg1 or 2 or 3 Under/Over.
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.
The history of alarms or codes of the unit are saved in the digital controller. The most
recent alarm or code is the first to be listed, with the time/date of the alarm or code at
the bottom of the screen. The controller stores up to 118 codes. When full, the controller
will automatically remove the oldest file. These codes will not be lost when the control
power toggle switch is powered off.
VOLTAGE
CONTROL
ADJUSTMENT
ON
RHEOSTAT
CONTROL
OFF
15