Tweco 300 S Arcmaster - Manual (Page 17)

ARCMASTER ® 300 S
March 31, 2006 2-3
2.05 Description
The Thermal Arc™ Model ARCMASTER 300 S is a self contained single/three-phase DC arc welding power source with Constant
Current (CC) output characteristics. This unit is equipped with a Digital Volt/Amperage Meter and lift arc starter for use with
Gas Tungsten Arc Welding (GTAW) and Shielded Metal Arc Welding (SMAW) processes. The power source is totally enclosed
in an impact resistant, fl ame resistant and non-conductive plastic case.
300A 5A (A)
(V)
OCV
18V
320A
16 0A
300A 25A (A)
(V)
OCV
10V
s s e c o r P G I T - T F I L s s e c o r P K C I T S
Figure 1 - Model 300 S volt-ampere curve
NOTE
Volt-Ampere curves show the maximum Voltage and Amperage output capabilities of the welding power source.
Curves of other settings will fall between the curves shown.
2.06 Functional Block Diagrams
Figure 2 illustrates the functional block diagram of the 300 S-power supply.
Main
Circuit
Switch
Filter
Input
Diode
Primary
Capacitor
DC Power
Voltage
Sensor
IGBT
Inverter
Thermal
Detector
To each control circuit
+/-15VDC +18VDC
+24VDC +5VDC
Trouble
Sensing
Circuit
Drive
Circuit
Torch Control
Connection
(CON1)
circuit
Current
Adjustment
Reference
Adjustment &
Mode select Switches
Panel Circuit Board
Sequence
Control
Themal
Sensor
Circuit
Main
Transformer
(PCB14)
Output
Diodes
Stick Mode
VRD
Sensing
Circuit
Lift T ig Mode
Output Short
Sensing
Circuit
Fan Control
Circuit
Fan
Hall Current
Transformer
(HCT1)
Output
Inductor
Thermal
Detector
+
-
+ -
Input
Power
Primary
Current
Sensor
Figure 2 - 300 S Model functional block diagram