2.5
Working
Principle
The working principle of GRAND TIG 400 DC PULSE is shown in the following figure. Three-phase 380V
line frequency AC is rectified into DC (about 530V), then is converted to medium frequency AC (
about 20KHz) by inverter device (IGBT), after reducing voltage by medium transformer (the main
transformer) and rectified by medium frequency rectifier (fast recovery diode), and is outputted by
inductance filtering. The circuit adopts current feedback control technology to insure current output
stability. Meanwhile, the welding current parameters can be adjusted continuously and steplessly to
meet with the requirements of welding craft.
2.6
Volt-Ampere
Characteristic
3
Installation
&
Operation
3.1
Layout for
the front
and rear
panel
（
1
）
“-” Output terminal.
（
2
）
TIG torch remote connection socket. *
（
3
）
TIG torch gas connector.
（
4
）
“+” Output terminal.
（
5
）
Inlet gas connector.
（
6
）
Water cooler remote connection socket.
（
7
）
Input power cable.
（
8
）
Power switch
Control Panel
（
9
）
LH multifunction display.*
（
10
）
Digital display value frequency indicator.
（
11
）
Digital display value time indicator.
（
12
）
Digital display value percentage indicator.
（
13
）
RH voltage display.
（
14
）
Welding output mode button.
（
15
）
Hf TIG mode indicator. *
（
16
）
Lift TIG mode indicator. *
（
17
）
MMA mode indicator.
（
18
）
2T trigger indicator.
（
19
）
4T trigger indicator.
（
20
）
Trigger control mode button. *
（
21
）
TIG parameter setting indicator. *
（
22
）
Parameter select/adjust Knob. *
（
23
）
MMA arc force setting Indicator. *
（
24
）
MMA welding current setting Indicator.
（
25
）
MMA hot start setting Indicator. *
（
26
）
Water cooling mode indicator
（
27
）
Air cooling mode indicator
（
28
）
Water /air cooling selection button.*
（
29
）
Alarm indicator. *
（
30
）
Water cooling system error indicator.*
（
31
）
Digital display value current indicator.
Water cooler
（
32
）
Water inlet.
（
33
）
Water return connector (red).
（
34
）
Water supply connector (blue).
（
35
）
The water cooling control connector.
*Denotes more detailed explanation of function to follow.
GRAND TIG 250 DC PULSE has excellent volt-ampere characteristic. Referring to the following
graph. In TIG welding, the relation between the rated loading voltage U2 and welding current I2
is as follows:
When I2≤600A
，
U2
＝
10
＋
0.04 I2
（
V
）
；
When I2
＞
600A
，
U2
＝
34
（
V
）
.
67
34
10
0
600
I
2
（
A
）
U
2
（
V
）
Working
point
Volt-ampere characteristic
The relation between the
conventional loading
voltage and welding current
