Theory of operation – Lincoln Electric MULTI-WELD SVM151-A User Manual

Page 34

ANALOG CONTROL POWER
SUPPLY BOARD AND WELD
CONTROL BOARD

The Analog Control Power Supply Board, which is pow-
ered by 40 VDC delivered from the DC Buss Power
Supply Board, supplies various regulated DC voltages
to operate the Weld Control Board circuitry. It also pro-
vides two regulated 20 VDC supplies to operate the
electronics on the Chopper Module Boards and applies
a 15 VDC supply to the Peripheral Board.

The Weld Control Board monitors the operator controls
(arc control, output control, hot start control, mode
selector switch, CC Slope switch and the remote con-
trol receptacle). It compares these commands to the

current and voltage feedback information it receives
from the shunt and output terminal circuits. The cir-
cuitry on the Weld Control Board determines how the
output should be controlled to optimize welding results,
and it sends the correct PWM gate signals to the IGBT
driver circuits. The Weld Control Board commands the
voltmeter and ammeter, which display both preset and
actual (while welding) voltage and current. The Weld
Control Board also controls the cooling fan motor and
the thermal indicator (light).

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THEORY OF OPERATION

MULTI-WELD 350