General Description; Input Power Source, Contactor And Dc Buss Power Supply Board - Lincoln Electric MULTI-WELD SVM151-A Service Manual

E-2
FIGURE E.2 – INPUT POWER SOURCE, CONTACTOR AND DC BUSS POWER SUPPLY BOARD
MULTI-WELD 350 BLOCK LOGIC DIAGRAM
INPUT
DIODES
ON/OFF
+
MODE
SWITCH
DC
(1/2)
POWER
SOURCE
(EXTERNAL)
_

GENERAL DESCRIPTION

The MULTI-WELD 350 Converter uses a single DC
input power source to provide up to 350 continuous
amps for positive polarity stick, wire processes, and
arc-air gouging. The machine converts higher volt-
age/lower current DC
voltage/higher current DC output power with over 90%
efficiency. This DC output is controlled by Chopper
Technology to produce DC current for multi-purpose
welding applications.
INPUT POWER SOURCE,
CONTACTOR AND DC BUSS
POWER SUPPLY BOARD
The Multi-Weld 350 receives DC input power from an
80 VDC buss Multi-Source (recommended), although
other external DC sources such as the Lincoln Electric
DC-1000, DC-655, or DC-600 can be used if they pro-
duce 50 VDC or above.
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.
THEORY OF OPERATION
INPUT
CONTACTOR
CR1
INPUT
CAPACITORS
20
VDC
x 2
ANALOG
DC
40
VDC
CONTROL
BUS
POWER
POWER
SUPPLY
SUPPLY
BOARD
BOARD
PERIPHERAL
input power to lower
MULTI-WELD 350
LEFT AND RIGHT
CHOPPER MODULES
IGBT
FREEWHEELING DIODE
CHOPPER MODULE
CHOKE
IGBT FREEWHEELING DIODE
CHOPPER MODULE
ON/OFF
VOLTS
MODE
SWITCH
(1/2)
GATE
SIGNALS
WELD
REGULATED CONTROL
VOLTAGES
BOARD
FAN
40 VDC
ARC
OUTPUT
15 VDC
FORCE
CONTROL
CONTROL
CR1
COIL
BOARD
INPUT
INDICATOR
LIGHT
The +50 VDC supply voltage is applied to the input
contactor via two large input diodes. The input contac-
tor establishes the electrical connection between the
Multi-Weld 350 and the power source when the
ON/OFF MODE switch is activated in either the con-
stant current (CC-stick) mode or the constant voltage
(CV-wire) mode.
A 40 VDC Buss Power Supply Board supplies 40 VDC
power to the Analog Control Power Supply Board,
which in turn feeds regulated voltages to a Weld
Control Board and 15 VDC to the Peripheral Board.
The Peripheral Board powers the input contactor coil
and the input indicator light on the front panel. The 40
VDC is also supplied to the Peripheral Board and is
passed on to the Weld Control Board.
TO ELECTRODE
CABLE
+
SHUNT
CURRENT FEEDBACK
TO WELD CONTROL BOARD
AMPS
REMOTE
RECEPTACLE
CC SLOPE
(STICK/GOUGE or PIPE)
HOT
THERMAL
START LIGHT
-
WORK
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