Lincoln Electric MULTI-WELD SVM151-A - Manual (Page 31)

General Description .......................................................................................................................E-2
Input Power Source, Contactor and DC Buss Power Supply Board ..........................................E-2
Power Modules and Feedback ...................................................................................................E-3
Analog Control Power Supply Board and Weld Control Board .................................................E-4
Mode Selector and Output Controls............................................................................................E-5
Protection Features.....................................................................................................................E-6
Insulated Gate Bipolar Transistor (IGBT) Operation...................................................................E-7
Pulse Width Modulation ..............................................................................................................E-8
Chopper Technology Fundamentals ...........................................................................................E-9
Section E-1 Section E-1
TABLE OF CONTENTS
- THEORY OF OPERATION SECTION -
MULTI-WELD 350
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CHOKE
IGBT
IGBT
SHUNT
WORK
TO ELECTRODE
CABLE
+
ANALOG
CONTROL
POWER
SUPPLY
BOARD
WELD
CONTROL
BOARD
ARC
FORCE
CONTROL
OUTPUT
CONTROL
HOT
START
DC
BUS
POWER
SUPPLY
BOARD
FAN
+
DC
POWER
SOURCE
(EXTERNAL)
_
REMOTE
RECEPTACLE
INPUT
DIODES
INPUT
CONTACTOR
MULTI-WELD 350 BLOCK LOGIC DIAGRAM
CC SLOPE
(STICK/GOUGE or PIPE)
PERIPHERAL
BOARD INPUT
INDICATOR
LIGHT
ON/OFF
MODE
SWITCH
(1/2)
CR1
CHOPPER MODULE
CHOPPER MODULE
ON/OFF
MODE
SWITCH
(1/2) VOLTS AMPS
THERMAL
LIGHT
FREEWHEELING DIODE
FREEWHEELING DIODE
REGULATED
VOLTAGES
CR1
COIL
15 VDC
CURRENT FEEDBACK
TO WELD CONTROL BOARD
20
VDC
x 2
-
INPUT
CAPACITORS
40
VDC
LEFT AND RIGHT
CHOPPER MODULES
GATE
SIGNALS
40 VDC
FIGURE E.1 – MULTI-WELD 350 BLOCK LOGIC DIAGRAM