MarelliMotori MARK X - M40FA644A Manuel Utilisateur page 13

5. CARD LAYOUT
5.1. Terminals
U
Power supply terminals
N
S1
Generator voltage sensing
...
terminals
S6
+ Output terminals (to the
- exciter field)
A Generator current sensing
B terminals
6 Terminals for connection to
8 external control device
9
Terminals for connection to
-
Varicomp M40FA621A
+
60 60Hz mode selection
Hz terminals
P Terminals for connection to
Q external potentiometer
Connection to ground for
internal EMI filter -
Connection to ground of
shield of shielded cables
5.2. Potentiometers
VOLT Setup of generator voltage.
Normally the internal potentiometer VOLT permits to adjuste the voltage in a wide range; to obtain a finer
possibility of voltage setting or to adjust the voltage from the control panel, or in order to limit the voltage range, an
MIN MAX
external potentiometer can be connected to the terminals P and Q (resistance about 100 kΩ, 1 W, for a voltage
regulation of ±5%).
Turn clockwise to increase voltage
FREQ Setup of the Corner Frequency.
It is usually set at the factory in order to reduce the excitation when speed becomes lower than 90% of rated
speed at 50 Hz (frequency lower than 45 Hz, or corner frequency). By removing the bridge which normally shorts
MIN MAX
the terminals Hz and 60, the speed protection operates properly for 60 Hz operation mode.
Turn clockwise to decrease the frequency threshold
STAB Setup of regulation stability.
The regulation can be set on the field to adapt it to the characteristics of the plant and the driving engine (diesel
engine, water turbine, gas turbine) in order to obtain the best voltage response. To change the stability
MIN MAX
characteristics of the regulator, the potentiometer STAB must be adjusted.
Turn clockwise to increase the stability
AMP Setup of the overexcitation threshold.
That limiter permits to protect the generator in case of over excitation due to load conditions that could cause the
rotor damage. Even if correctly set, this function does not substitute external systems protections, it is only a
MIN MAX
completing device.
Turn clockwise to increase the limitation intervention threshold
SLOPE Setup of the low speed protection characteristic slope.
With the micro-switch 4 OFF, this potentiometer allows to increase or decrease the under-speed ramp slope, and
set the voltage droop for a fixed reduced speed.
MIN MAX
Turn clockwise to decrease the voltage dip
AMP
FREQ
VOLT
P
Q
60
Hz
YELLOW
RED
PAR LED LED
A
B
8
6
9 +
-
STAB SLOPE
S6 S5 S4 S3 S2 S1 - + N U
ON
1 2 3
F
U
S
OFF
E
Micro-switches 1-4
13
4