1 - FUNCTIONAL
This card controls from "AUTO" and "MANU" voltage
reference and some additional informations detailed in
the following, the exciter field current supply by the regu-
lator and the booster (if used).
- Three operating mode are possible, depending of ex-
ternal informations :
• Normal mode with 110% ceiling of If nominal.
• Ceiling unlocked mode (160% minimum Ifield nomi-
nal) depending of the command input from the PID card
with limited delay and alarm output in case of sustained
undervoltage.
• Maximum ceiling mode if the synchronisation voltage
desappears ( machine short-circuit) with limited (adjusta-
ble) field current.
- The "AUTO" or "MANU" reference voltage depending of
the associated command input and also of the active
limitations, is compared to the field current measurement
and gives the error voltage which is after integration,
compared to a sawtooth feed by the synchronisation vol-
tage. The output of this stage is a variable duty cycle
signal which controls the power transistors throught iso-
lating optocouplors.
- This card can be supplied in three manners :
• From the general supply of the rack in normal opera-
tion
• Throught an isolated supply taken from the field
voltage during start-up or generator short-circuit (Rack
supply not present)
• Directly from the field voltage for power transistor
command.
The permanent limitation (110% de Iexc nominal) can
be modified by the following conditions:
- Field ceiling unlocking on machine undervoltage condi-
tion. It inccreases from 110% (normal operation) to a
minimum of 160% of the nominal field current during an
adjustable time delay and then go back to 110%. An
alarm is activated if this undervoltage is sustained after-
ward.
- Field ceiling unlocking on synchronisation voltage ab-
cence. It increases to the maximum given by the sett-ing
of P7.
- Field ceiling limitation caused by power heatsink over-
heating. On thermocontact action the ceiling is reduced
to a value given by the setting of P8.
A separate circuit monitors the instantaneous current of
the power transistor and reduces immediatly the com-
mand signal if its value increases above a fixed value.
(Exciter or wiring short-circuit protection ).
2 - ADJUSTMENTS
- P1 : Integrator time constant adjust.
- P2 : Unlocked ceiling time delay adjust. (generally 5s)
- P3 : Alarm time delay adjust after ceiling unlock.
- P4 : Permanent ceiling value adjust (generally 1,1If no-
minal)
- P5 : HALL sensor range adjust.
- P6 : Initial ramp-up adjust
- P7 : Maximum field current adjust (machine short-circuit)
- P8 : Maximum fieeld current in case of heatsink over-
heating.
3 - INPUTS / OUTPUTS
Flat cable (BUS 64points)
- 15c
: If reference set point input "AUTO" channel
- 15a
: If reference set point input "MANU" channel
- 25a
: "AUTO / MANU" command input (0V = "AUTO")
- 9c
: Unlocking ceiling command input
- 4a, 4c
: Synchronisation voltage input
- 26c
: Heatsink thermocontact input
- 1a,1c
: +15Vdc regulated (Vcc)
- 32a,32c : -15Vdc regulated (Vdd)
- 16a,17c : Common ground (GND or 0V)
- 17a
: Field current measure output
- 19a
: End of ramp-up output signal
- 31a
: Alarm output
Card connector (8 points)
- 1 : Field voltage
- 2 : Main transistor drain
- 3 : Main transistor gate
- 4 : Booster transistor gate
- 5 : Power ground
- 6 : +Vcc HALL sensor
- 7 : -Vcc HALL sensor
- 8 : HALL sensor measure output
22
Driver
card
AVR
Model R630
NT1950070/b-11/93 f:1/3
