Theory Of Operation; Section E; General Description - Lincoln Electric POWER MIG SVM165-A Service Manual

E-2
RECONNECT
PANEL
LINE
SWITCH
115 VAC AUX.
RECEPTACLE
FAN
MOTOR
FOOT AMPTROL OR REMOTE (6-PIN AMPHENOL)
SPOOL GUN OR PUSH-PULL GUN (7-PIN AMPHENOL)
GAS
SOLENOID

GENERAL DESCRIPTION

The Power MIG 350MP is a complete semiautomatic,
multi-process DC arc welding machine offering CV and
CC DC welding. It is rated for 350 amps, 32 volts, at
60% duty cycle. The standard machine is equipped to
weld CC Stick, CC-GTAW, CV-FCAW, and synergic
and non-synergic CV GMAW/GMAW-P, Pulse-on-
Pulse, and Power Mode welding processes.
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.

THEORY OF OPERATION

FIGURE E.2 – GENERAL DESCRIPTION
MAIN
OUTPUT
TRANSFORMER
RECTIFIER
+
60
VAC
30
40 VDC
115
VAC
VAC
DIODE CONTROL
RECTIFIER
RELAY
CHOPPER
SEC
40
VDC
FROM WELD
CONTROL BOARD
THERMOSTATS
40 VDC
SPOOL
SHIELDED
FEEDER
GUN
24 VDC CABLE
BOARD
BOARD
GAS
SOLENOID
WIRE DRIVE
MOTOR
POWER MIG 350MP
CHOPPER
OUTPUT
ASSEMBLY
CHOKE
IGBT
CURRENT
80
TRANSDUCER
VAC
CURRENT
FEEDBACK
POWER
20 VDC
BOARD
PWM
SIGNALS
+15/-15/+5 VDC
IGBT
DRIVE
WELD CONTROL BOARD
ARCLINK SHIELDED CABLE AND SPI COMMUNICATIONS
+5 VDC
ENCODER
MSP
BOARD
(Below code 10900)
GUN TRIGGER AND THUMB SWITCH
SPOOL GUN
T PUSH-PULL
A
SWITCH
C
Mechanical Encoders
H
(Above code 10900)
The digital microcomputer based control system allows
easy and accurate adjustment of weld parameters
through the multi-process panel located on the front of
the machine. The Power MIG 350MP is equipped with
a 6-pin connector for a foot amptrol or remotes and a 7-
pin connector to allow operation of a spool gun or a
push-pull gun for feeding aluminum wires.
POS
OUTPUT
GUN
TERMINAL
+
_
NEG
OUTPUT
TERMINAL
VOLTAGE
FEEDBACK
RS232
CONNECTOR
TO FAN RELAY
DISPLAY
BOARD
BOARD
E-2