Lincoln Electric POWER MIG SVM157-A - Manual (Page 29)

TABLE OF CONTENTS
- THEORY OF OPERATION SECTION -
POWER MIG 200
Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Section E
Input Power Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-2
Input Line Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-2
Main Transformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-2
Voltage Selector Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-2
Baffle Mounted Diode Bridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-2
Control Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-3
Output Rectification, Contactor & Control Boards . . . . . . . . . . . . . . E-3
Optional Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-4
Control Board, Gun Trigger, & Wire Drive Motor . . . . . . . . . . . . . . . E-4
Protective Devices & Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-5
Thermal Overload Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-5
Wirefeed Overload Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-5
Section E Section E
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FIGURE E.1 THEORY OF OPERATION BLOCK DIAGRAM
LINE
SWITCH
RECONNECT
PANEL
FAN
MOTOR RECTIFIER
DIODE
BRIDGE
CONTROL BOARD
GAS
SOLENOID
WIRE
SPEED
CONTROL
WIRE
DRIVE
MOTOR
TACH
FEEDBACK
GUN TRIGGER
+
-
OUTPUT DIODE
BRIDGE
+
-
NEGATIVE
TERMINAL
CONTACTOR
CONT
ACT
OR
CONTROL
TAP SELECTOR
SWITCH
OUTPUT
CHOKE POSITIVE
TERMINAL
TRANSFORMER
THERMOSTAT OUTPUT BRIDGE
THERMOSTAT
28 V
AC
MAIN
TRANSFORMER
OUTPUT
CAPACITORS
GUN
ASSEMBLY