Theory of operation, Mode selector and output controls, Figure e.5 – mode selector and output controls – Lincoln Electric MULTI-WELD SVM151-A User Manual
Page 35
MODE SELECTOR AND OUTPUT
CONTROLS
In CC mode, machine output is at open circuit voltage.
The OUTPUT control presets amps in the 30 to 350 A
range and then adjusts actual welding current to match
the preset when welding. In CV mode, machine output
is at the voltage level set at the OUTPUT control. The
OUTPUT control presets volts, then adjusts the actual
arc voltage to match the preset when welding.
A HOT START control is provided to enhance arc start-
ing with an adjustable output “boost” in either CC or CV
mode. The ARC FORCE control (CC mode only) pro-
vides extra weld current to prevent electrode “stubbing”
An additional CC SLOPE switch improves “fast-freeze”
stick electrode performance during vertical pipe weld-
ing when set to the PIPE position.
E-5
E-5
THEORY OF OPERATION
MULTI-WELD 350
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.
CHOKE
IGBT
IGBT
SHUNT
WORK
TO ELECTRODE
CABLE
+
ANALOG
CONTROL
POWER
SUPPLY
BOARD
WELD
CONTROL
BOARD
ARC
FORCE
CONTROL
OUTPUT
CONTROL
HOT
START
DC
BUS
POWER
SUPPLY
BOARD
FAN
+
DC
POWER
SOURCE
(EXTERNAL)
_
REMOTE
RECEPTACLE
INPUT
DIODES
INPUT
CONTACTOR
MULTI-WELD 350 BLOCK LOGIC DIAGRAM
CC SLOPE
(STICK/GOUGE or PIPE)
PERIPHERAL
BOARD
INPUT
INDICATOR
LIGHT
ON/OFF
MODE
SWITCH
(1/2)
CR1
CHOPPER MODULE
CHOPPER MODULE
ON/OFF
MODE
SWITCH
(1/2)
VOLTS
AMPS
THERMAL
LIGHT
FREEWHEELING DIODE
FREEWHEELING DIODE
REGULATED
VOLTAGES
CR1
COIL
15 VDC
CURRENT FEEDBACK
TO WELD CONTROL BOARD
20
VDC
x 2
-
INPUT
CAPACITORS
40
VDC
LEFT AND RIGHT
CHOPPER MODULES
GATE
SIGNALS
40 VDC
FIGURE E.5 – MODE SELECTOR AND OUTPUT CONTROLS