Lincoln Electric POWER MIG SVM165-A - Manual (Page 35)

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Section E-1 Section E-1
POWER MIG 350MP
Theory of Operation .............................................................................................................Section E
General Description .......................................................................................................E-2
Input Voltage and Main Transformer ..............................................................................E-3
Input Rectifier, Chopper Assembly and Feedback .........................................................E-4
Diode Control Rectifier and Power Board ......................................................................E-5
Weld Control Board ........................................................................................................E-6
Wire Drive Motor and Feedback .....................................................................................E-7
Thermal Protection, Over Current Protection, and Wire Feeder
Overload Protection .................................................................................................E-8
Insulated Gate Bipolar Transistor (IGBT) Operation .......................................................E-9
Pulse Width Modulation ..........................................................................................E-10
Chopper Technology Fundamentals........................................................................E-11
TABLE OF CONTENTS
-THEORY OF OPERATION SECTION-
FIGURE E.1 – POWER MIG 350MP BLOCK LOGIC DIAGRAM
IGBT
+
LINE
SWITCH
RECONNECT
PANEL
MAIN
TRANSFORMER
RELAY
SPOOL
GUN
BOARD
FEEDER
BOARD MSP
BOARD ENCODER
BOARD DISPLAY
BOARD
RS232
CONNECTOR
WELD CONTROL BOARD
SPOOL GUN
PUSH-PULL
SWITCH
WIRE DRIVE
MOTOR
OUTPUT
RECTIFIER CHOPPER
ASSEMBLY
OUTPUT
CHOKE
CURRENT
TRANSDUCER
GUN
POS
OUTPUT
TERMINAL
NEG
OUTPUT
TERMINAL
POWER
BOARD
DIODE CONTROL
RECTIFIER
FAN
MOTOR
FOOT AMPTROL OR REMOTE (6-PIN AMPHENOL)
SPOOL GUN OR PUSH-PULL GUN (7-PIN AMPHENOL)
GAS
SOLENOID
SEC
THERMOSTATS
_
+
115
VAC
30
VAC
60
VAC
80
VAC
40 VDC
40
VDC
40 VDC
24 VDC
20 VDC
PWM
SIGNALS
+15/-15/+5 VDC
SHIELDED
CABLE
GUN TRIGGER AND THUMB SWITCH
SHIELDED CABLE AND SPI COMMUNICATIONS ARCLINK
+5 VDC
CURRENT
FEEDBACK
VOLTAGE
FEEDBACK
FROM WELD
CONTROL BOARD
TO FAN RELAY
IGBT
DRIVE
T
A
C
H
CHOPPER
(Below code 10900)
Mechanical Encoders
(Above code 10900)
GAS
SOLENOID
115 VAC AUX.
RECEPTACLE