Preliminary Checks - MarelliMotori MARK X User Manual

10.2. DC voltage signal from external control device
The AVR accepts a DC voltage analogue input of +/-3 V (maximum range), to control the exciter field of the generator.
This input has to be applied to terminals 6 and 8.
In case of single operation, a maximum change of +/-3 V of the analogue input leads to a maximum change of +/-25% of the
generator voltage, with respect to the rated generator voltage.
A value of 0 V at 6 and 8 terminals does not lead to any change in excitation.
The analogue input is usually used for the voltage regulator control by means of the Marelli power factor regulator, for parallel
operation with the grid.
This input can be also connected to external devices not made by Marelli, for remote control of the generator voltage or the
excitation during parallel operations (voltage matching and power factor regulation), as long as those devices were equipped
with suitable outputs (insulated outputs, and voltage regulation range not higher than +/-3 V).
WARNING: in the case of parallel with the grid, and voltage regulator controlled by an external device by means of the
analogue input, pay attention to the analogue input voltage value after the load rejection.
In this particular case, in order to avoid any dangerous generator over-voltages, the voltage value between the terminals 6 and
8 must be reduced to 0 V or to any values leading to a generator voltage not exceeding the rated + 5%.
11. FUSE
The voltage regulator is provided with an internal protecting fuse (which acts in case of faults on the regulator or very large
overloads on exciter circuit).
12. EMI SUPPRESSOR
The AVR is provided with an internal Electromagnetic Interference filter: this interference suppression system permits to obtain
compliance with relevant EMC standards on MARELLI MOTORI generators.
13. ACCESSORY
Description
Fuse (Ultra rapid, ceramic, 10 A – 500 V)
External potentiometer (100 k - 2 W)

14. PRELIMINARY CHECKS

14.1. Visual inspection
Check the integrity of the following AVR
components (see Figure):
1. Power resistor pins
2. Power diodes
3. Fuse
Check that no resin is present on:
4. the potentiometers
5. the dip-switch block.
Check finally:
6. the orange bridge is installed on
terminals 60 and Hz (for 50Hz
generators)
Part number
963823010 - 10003249
963824430 - 10000302
P
Q
60
Hz
BRIDGE
A
B
DIP-SWITCHES
8
6
M
+
9-M -
POTENTIOMETERS
+
S6 S5 S4 S3 S2 -
S1
POWER RESISTOR
POWER DIODES
FUSE
N U
16