Lincoln Electric POWER WAVE SVM173-A - Manual (Page 42)

OUTPUT RECTIFIER AND CHOKE
The output rectifier receives the AC output from the
main transformer secondary and rectifies it to a DC
voltage level. Since the outuput choke is in series with
the negative leg of hte output rectifier and also in series
with the welding load, a filtered DC output is applied to
the machine output terminals. Refer to Figure E.7.
When in the STT mode, the control circuit monitors
the voltage conditions at the arc, and turns the STT
chopper module on or of as necessary to generate an
STT output waveform. The STT current transducer in
the STT circuit signals the control board to limit output
to 375 amps maximum.
E-8 E-8
THEORY OF OPERATION
POWER WAVE 455M/MSTT Retur
n to Section TOC
Retur
n to Section TOC
Retur
n to Section TOC
Retur
n to Section TOC
Retur
n to Master TOC
Retur
n to Master TOC
Retur
n to Master TOC
Retur
n to Master TOC
FIGURE E.7 – OUTPUT RECTIFIER, OUTPUT CHOKE AND STT CHOPPER BOARD
+
+
INPUT
BOARD
RECONNECT
SWITCH
LEFT
SWITCH
BOARD
RIGHT
SWITCH
BOARD
INPUT
RECTIFIER CR1
GATEWAY
BOARD
DC
BUS
BOARD
FEED
HEAD
BOARD
POWER
BOARD
CONTROL
BOARD
STT CHOPPER
BOARD
OUTPUT
CHOKE
STT
ELECTRODE
TERMINAL
ELECTRODE
TERMINAL
THERMOSTATS
T1
T2
AUX
RECONNECT
RELAY
WATER
COOLER
115 VAC
RECP.
115 VAC
FAN
ARC LINK
WIRE
FEEDER
RECP.
S1
S6
CONNECTION
TO WIRE
DRIVE
S1
S6
VOLT
SENSE
BOARD
MAIN
TRANSFORMER
S5
CONTACTOR AND PRECHARGE
CONTROL SIGNALS FROM
CONTROL BOARD
FROM CONTROL
BOARD 2
4
V
A
C
115 VAC
52 VAC
230 VAC
40 VDC
40 VDC
40 VDC
+20 VDC
TO
CHOPPER
BOARD
40 VDC
ARC LINK
CONNECTION
TO
ROBOT
VOLTAGE SENSE
OUTPUT
+20 VDC FROM
POWER BOARD
CT CURRENT
TO CONTROL
BOARD
CAP. V/F
FEEDBACK
CAP. V/F
FEEDBACK
IGBT DRIVE
FROM
CONTROL
BOARD
CT CURRENT
TO CONTROL
BOARD
-15 V
+15 V
+5 V
+5 V ARC LINK
+5V RS232
+15V SPI
STATUS THERMAL
LIGHT LIGHT
S2 WORK
SENSE
LEFT S.B.
CAP. V/F
RIGHT S.B.
CAP. V/F
S3
RS232
LEFT CT
CURRENT
FB
C
U
R
R
E
N
T
F
B
S
T
T
F
B
STT
DRIVE
ARC LINK
IGBT
DRIVES
TO
LEFT
S.B. TO
RIGHT
S.B.
67A
67B
SW1
BUS BOARD
RECTIFIER
CURRENT
TRANSDUCER
CURRENT
TRANSDUCER
OUTPUT DIODES
D1 -D4
115 VAC
40 VDC
DEVICE NET
VOLTAGE SENSE SELECT
IGBT DRIVE
FROM
CONTROL
BOARD
+5V SPI
RIGHT CT
CURRENT
FB
TO FAN RELAY
CONTACTOR AND
PRECHARGE
CONTROL SIGNALS
65 VDC
WORK
TERMINAL
POWER WAVE 455/R