MarelliMotori MARK XX Manual Del Usuario página 16

7. SETUP PROCEDURE
Initial settings
- With the generator shut down, initially position the regulator potentiometers as indicated in the following figure:
where:
❖ MIN
potentiometer turned completely counter clockwise;
❖ ½
❖ MAX
potentiometer turned completely clockwise.
NOTE: Whenever there is an external potentiometer connected to terminals P and Q, that potentiometer must
be set midway.
- By removing the bridge which normally shorts the terminals Hz and 60, the speed protection operates properly
for 60 Hz operation mode.
Voltage setting
- Start the generator and bring it to nominal speed: the voltage at the output terminals of the generator must be
less than the generator's rated voltage.
- Turn the VOLT potentiometer clockwise until the generator output voltage reaches a value equal to about the
rated voltage.
Setting the under-frequency limiter
- Decrease the generator rotation speed to 90% of the nominal speed.
- Turn the U/F potentiometer counter clockwise until the generator voltage starts to decrease below the rated
value of the machine.
- Return the rotation speed to the nominal value of the machine and check that the generator voltage is at the
rated value.
NOTE: This setting allows to set the corner frequency to 45Hz to, for operating frequency of 50Hz.
Improvement of response speed / regulation stability
- Improvement of response speed: turn the STAB potentiometer slightly counter clockwise, being sure you don't
reach a generator voltage oscillation or overshoot.
Improvement of regulation stability: turn the STAB potentiometer slightly clockwise.
- Apply a load to the generator and check the voltage transient.
Then, release the load and check the voltage transient.
- Repeat the previous points until you reach the regulation stability or response speed desired (which is also
obviously related to the type of machine and load given).
U/F
MIN
MAX
MAX
potentiometer about midway;
VOLT STAB
MIN
MIN MAX MAX
MIN ½