Overboosting Device Varicomp - MarelliMotori M8B 250 Instrucciones Y Advertencias De Seguridad

This source could consist of a bank of batteries or of a voltage transformer and a rectifier unit connected at the alternator output.
- disconnect the two exciter stator terminals (red wire +, blue wire -) from AVR;
- apply the D.C. power supply to these two wires;
- set the rheostat R to adjust the alternator output voltage.
WARNING: compensate by manually increasing excitation as the load increases.
Before removing the load, reduce the excitation current
Use the following table to select the rheostat:

5.4. Overboosting device VARICOMP

The overexcitation device is composed of an electronic device and a current transformer (C.T.), and acts in case of sudden overloads
or in case of short circuit.
The current transformer supplies a current proportional to the load current; this current is rectified and then added to the current given
by AVR. The current transformer is normally short circuited and it does not act on excitation in normal operation conditions. The current
transformer is only inserted if the output voltage drops below 70% of rated value.
If the voltage increases as the load is increasing, then the intervention of the Varicomp device has to be modified by using on the
internal potentiometer of the electronic board, by rotating it anticlockwise.
B1
CT
A1
BLUE
EXCITER
STATOR
WINDING
TERMINALS
RED
Generator
M8B 250
+ - ∼
AVR
24 V
R
I max
[A]
5
Potentiometer to modify intervention of the
overboost
⇒ intervention at higher voltage
⇒ intervention at lower voltage
14
ENGLISH
Max. resistance of rheostat
[Ω]
80