Output Rectifier, Output Choke And Stt Chopper Board - Lincoln Electric POWER WAVE SVM156-A Service Manual

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FIGURE E.7 – OUTPUT RECTIFIER, OUTPUT CHOKE AND STT CHOPPER BOARD
POWER WAVE 455/R
CR1
RECTIFIER
SW1
INPUT
BOARD
CONTACTOR AND PRECHARGE
CONTROL SIGNALS FROM
CONTROL BOARD
2
FROM CONTROL
4
BOARD
V
AUX
A
RECONNECT
C
RELAY
115 VAC
52 VAC
T1
230 VAC
115 VAC
T2
OUTPUT RECTIFIER, OUTPUT
CHOKE AND STT CHOPPER
BOARD
The output rectifier receives the AC output from the
main transformer secondary and rectifies it to a DC
voltage level. The output choke is in series with the
negative leg of the output rectifier and also in series
with the welding load. Due to the current "smoothing"
capability of the output choke, a filtered DC output cur-
rent is applied through machine output terminals to the
welding arc.
THEORY OF OPERATION
IGBT DRIVE
FROM CT CURRENT
TO CONTROL
CONTROL
BOARD
BOARD
CAP. V/F
FEEDBACK
LEFT
SWITCH
INPUT
BOARD
IGBT DRIVE
RECONNECT
FROM
CT CURRENT
SWITCH
CONTROL
TO CONTROL
BOARD
BOARD
RIGHT
SWITCH
CAP. V/F
FEEDBACK
BOARD
67A
S1
VOLT
67B
SENSE
S6
VOLTAGE SENSE
BOARD
OUTPUT
VOLTAGE SENSE SELECT
FEED
40 VDC
HEAD
115 VAC BOARD
FAN
65 VDC
CONNECTION
S6
TO WIRE
DC
BUS BOARD
RECTIFIER
BUS
BOARD
40 VDC
WATER
40 VDC
COOLER
40 VDC
ARC LINK
115 VAC
WIRE
RECP.
S1
FEEDER
RECP.
POWER WAVE 455/R
MAIN
TRANSFORMER
OUTPUT DIODES
D1 -D4
DEVICE NET
S5
GATEWAY
CONNECTION
ARC LINK TO
BOARD
ROBOT
40 VDC
ARC LINK
+5V RS232
+5 V ARC LINK
POWER
+5V SPI
DRIVE
BOARD
+15V SPI
+5 V
+15 V
-15 V
+20 VDC
TO
CHOPPER
BOARD
LEFT CT
CURRENT
FB
The STT Chopper Board is in series with the STT out-
put terminal and is used to interrupt the welding cur-
rent for very short periods of time during the short-arc
MIG welding process. The IGBT modules incorporat-
ed on this board receive their gate firing commands
from the Control Board.
ELECTRODE
TERMINAL
+
+20 VDC FROM
POWER BOARD
STT
CURRENT
ELECTRODE
STT CHOPPER TRANSDUCER
TERMINAL
BOARD
+
STT
DRIVE CURRENT
WORK
TRANSDUCER
OUTPUT
TERMINAL
CHOKE
C
U
R
S
R
T
TO
TO E
T
RIGHT
LEFT
N
S.B.
S.B.
T
F
B
F
B
TO FAN RELAY
IGBT
DRIVES
CONTACTOR AND
PRECHARGE
CONTROL SIGNALS
THERMOSTATS
CONTROL
BOARD
S2 WORK
SENSE
S3
RS232
LEFT S.B.
CAP. V/F
RIGHT S.B.
CAP. V/F
RIGHT CT
CURRENT
FB
STATUS THERMAL
LIGHT LIGHT
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