THEORY OF OPERATION

E-3 E-3

VANTAGE® 400

FIGURE E.3 — WELD WINDINGS, RECTIFIER, CHOPPER MODULES & FEEDBACK

W
E
L
D
W
I
N
D
I
N
G
30AUXILIARY WINDINGS10 + 30ROTOR
+
REMOTE
AMPHENOL
ARC
CONTROL
OUTPUT
CONTROL
PROCESS/RANGE
SELECTOR
WELD
CONTROL
BOARD
THREE-PHASERECTIFIERWORKTERMINALELECTRODETERMINALCHOPPER MODULEIGBTCHOKEVOLTMETERAMMETERPWMSIGNAL
VRD
VOLTAGE REDUCTION
VRD FEEDBACK
VRD
LIGHTS
RG
VRD
SWITCH
(OFF)
SHUNT
AUX. FEEDBACK
120VAC
RECEPTACLED (2)
AUX
CURRENT
TORROID
42 VAC TO 14 PIN AMPHENOL
FOR WIRE FEEDER
240 VAC
30
240VAC
RECEPTACLE
LOW IDLE COMMAND
F
E
E
D
B
A
C
K
C
U
R
R
E
N
T
I
D
L
E
V.R.D.
POWER TO CONTROL BOARD
POWER TO
VRD
80 VDC
VOLT
FEEDBACK
+

-

ENGINE
GLOW PLUGS
MECHANICAL
ROTATION
STARTER
ALTERNATOR
BATTERY
OIL PRESS
TEMP
ROTOR
FLASH
ENGINE PROTECTION
IDLER CONTROL
P.C. BOARD
STATOR
SLIP
RINGS
+-
RUN/STOP
SWITCH (RUN) ENGINE
SENSORS
ENGINE
TROUBLE
LIGHT
Y
ALT
SOL SOL
ALT FLASH
S
H
U
T
D
O
W
N
I
D
L
E
R
+-YALTERNATORLIGHT

NOTE: Unshaded areas of Block Logic

Diagram are the subject of discussion

WELD WINDINGS, RECTIFIER,POWER MODULES ANDFEEDBACK

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.

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. See

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.

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