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
Potentiometer to modify intervention of the
overboost
⇒ intervention at higher voltage
⇒ intervention at lower voltage
+ - ∼
AVR
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