MarelliGenerators MJB 160 Instrucciones Y Advertencias De Seguridad página 28

Radio interference suppressor
The voltage regulator is internally provided with radio interference suppressor, in order to limit the radio interference from the
generators MJB to within levels stated by C.E. standards for industrial areas.
Fuse
On the AVR there is a protecting fuse. In case it should be necessary to replace it, high speed fuses should be used; in addition they
should have high breaking resistance with a rated voltage of 500V, and rated current of 10A.
Connection of AVR
The AVR is connected to the terminals of the generator and to exciter using FAST-ON terminals.
ATTENTION! When changing generator wiring diagram, it is advisable to pay attention to connection of AVR, in order to
avoid AVR damages.
VOLT
PAR
Varicomp
USE OF POTENTIOMETERS
VOLT - Potentiometer for adjusting the output voltage of the generator.
It allows a wide range of voltage setting. In case of resetting this potentiometer the voltage has to be set within 5% of the rated
voltage of the machine.
In order to obtain a finer regulation, or to adjust the voltage from control panel or to limit the voltage range, it is possible to insert
an external potentiometer (see paragraph 5.2).
⇒ increase voltage
FREQ - Potentiometer for changing the low speed protection.
Usually it is set in order to reduce the excitation when the speed is 10 % below the rated value at 50 Hz. By removing the bridge
which is normally shorting terminals "60-Hz", the low speed protection acts properly for 60 Hz. In case of intervention, red led
switch on.
⇒ decrease frequency of intervention
AMP - Potentiometer for chancing the over excitation limit device.
This function permits to limit the over-excitation due to particular load conditions that could cause the generator damage.
As soon as the excitation voltage rises over a certain threshold, set by means of the potentiometer AMP, for a time larger than
the limiter time delay, the over-excitation limiter steps-down the excitation voltage to the threshold value.
Limiter time delay depends on the amount of the over-load: more the over-load arisen, quicker the limiter action.
Limiting the excitation voltage, the generator voltage decreases, in partial or total way, depending on the over-load occured. In
case voltage shutdown is due to the limiter, it could be not maintained.
WARNING: Even if correctly set, this device does not substitute external systems protections, it is only a completing
device.
⇒ increase the over excitation threshold
For a limiter setting, it is possible to momentarily disable the time delay, by means of the micro-switch 3 (see also the next
paragraphs).
SIN.UM.017.11
STAB
AMP
FREQ
P
Q
60
Hz
RED YELLOW
LED LED
A
B
8
6
9 +
- S6 S5 S4
Three phase
voltage
reference
SLOPE
F
U
S
+
S3 S2 S1 - N U E
Supply
Exciter
stator
⇒ decrease voltage
⇒ increase frequency of intervention
⇒ decrease the over excitation threshold
28
ON
1 2 3 4
OFF
mini switches 1-4
ENGLISH