Lincoln Electric VANTAGE 400 Service Manual page 43

E-3
FIGURE E.3 — WELD WINDINGS, RECTIFIER, CHOPPER MODULES & FEEDBACK
GLOW PLUGS
ENGINE
STARTER
ALT
ALTERNATOR
SOL SOL
RUN/STOP
SWITCH (RUN)
S
H
U
I
T
D
D
L
O
+ E
W
R
N
BATTERY
-
ENGINE PROTECTION
Y
IDLER CONTROL
P.C. BOARD
ENGINE
Y
TROUBLE
LIGHT
ALTERNATOR
LIGHT
WELD WINDINGS, RECTIFIER,
POWER MODULES AND
FEEDBACK
The three-phase stator weld windings are connected to
a three-phase rectifier bridge. The resultant DC voltage
is applied to four paralleled capacitors incorporated
within each of the two power modules. There are two
capacitors in each module. These capacitors function
as filters and also as power supplies for the IGBTs.
See IGBT Operation in this section. The IGBTs act as
high-speed switches operating at 20KHZ. These
devices are switched on and off by the Weld Control
PC board through pulse width modulation circuitry.
See Pulse Width Modulation in this section.
THEORY OF OPERATION
STATOR
MECHANICAL
ROTATION
SLIP
RINGS
+ -
OIL PRESS
ENGINE
SENSORS
TEMP
AUX
CURRENT
TORROID
ROTOR
FLASH
NOTE: Unshaded areas of Block Logic
Diagram are the subject of discussion
VANTAGE® 400
THREE-PHASE
RECTIFIER
+
80 VDC
W
I
D
N
L 30
D
E VRD
I
N VOLTAGE REDUCTION
W
G
R G
VRD
LIGHTS
ROTOR
REMOTE
AMPHENOL
10 + 30 42 VAC TO 14 PIN AMPHENOL
FOR WIRE FEEDER
WINDINGS
AUXILIARY
240 VAC
30
240VAC
RECEPTACLE
AUX. FEEDBACK
120VAC
RECEPTACLED (2)
LOW IDLE COMMAND
This "chopped" DC output is applied through choke
coils and a shunt to the welding output terminals. The
choke functions as a current filter, and it helps to bal-
ance the outputs of the two power modules. Free-
wheeling diodes are incorporated in the power mod-
ules to provide a current path for the stored energy in
the choke when the IGBTs are turned off.
Chopper Technology in this section.
Output voltage and current feedback information is fed
to the Weld Control PC board. This information is
sensed from the output terminal circuits and the shunt.
WORK
TERMINAL
-
CHOPPER MODULE
ELECTRODE
TERMINAL
IGBT
+
CHOKE
SHUNT
F
C
E
U I
E
R D
VRD FEEDBACK
D
R L
B
E E
A
N
PWM
C
T
VRD
K
SIGNAL
SWITCH
(OFF)
WELD
CONTROL
BOARD
VOLTMETER
AMMETER
OUTPUT PROCESS/RANGE
ARC
CONTROL CONTROL SELECTOR
E-3
See