
CHAPTER 1 - DESCRIPTION
49'1335 e
AMX DPS DC-POWER MODULE
5
Functions of the PC-Boards
As already mentioned are all converter control
and regulation functions executed in the
AutoMax and Power Module Interface Rack
outside the power unit. This covers also the
functions for firing pulse generation including the
pulse amplification (final stage) and functions for
analogue to digital signal conversion and the
measuring signals for line voltage, line
synchronization, armature current and armature
voltage from the power stack.
The only function of the cards on the power unit
is to detect, calibrate and transfer the measuring
and feedback signals. In addition the firing
pulses are transferred to the power unit. The
cards contain also the snubber circuits for the
power unit.
The functions are distributed on the cards as
follows:
Driver Card
The firing pulse transformers are placed on the
card:
PDA for 4Q drives S-6R, or
PDB for 1Q drives S-6
The driver signals are distributed through series
resistors to the adjacent transformers. The
secondary side of the firing pulse transformers is
connected via twisted pairs to the thyristors.
Feedback Card
Synchronization
For the synchronization of the firing pulses the
DPS-System needs a 3-phase-AC voltage signal.
These signals are generated from the secondary
windings of the transformers T1-T3.
The transformers, on the primary side in delta
connection, are linked to the mains through input
fuses F1-F3.
The circuit calibrates the line voltage to the
required signal amplitude and isolates the
signals from the line voltage. The transformer
secondary windings in star-connection are linked
through resistive voltage dividers to connector
X1.
The signal amplitude is adapted for different line
voltages by means of jumper setting according to
Table 3-1 in Chapter 3.
Line Voltage and Armature Voltage Feedback
5 high resistance voltage dividers are provided
for 3 line voltage and 2 armature voltage
feedback signals. The signal amplitude is
adapted for different line voltages by means of
jumper setting accord. to Table 3-1 in Chapter 3.
Current Feedback
The current feedback signal originates from 2
current transformers (CT1 and CT3) monitoring
the AC line current to the SCR bridge. The CT
connections are directly linked to connector X1
and then rectified and summed on a burden
resistor in the PMI. The voltage across the
burden resistor is fed back to the feedback card
in the power module and there available at test
points ARM CT and GND.
Voltage Limitation (Snubber) Circuit
For power modules up to type 800 A the feed-
back card also includes the snubber circuit.
SBA card
This card contains the voltage limitation
(snubber) circuit for 1500 –2000 A units.