2.3
Brief
Introduction
GRAND TIG 200 DC adopts the latest Pulse Width Modulation (PWM) technology and the Insulated
Gate Bipolar Transistor (IGBT) power modules. It uses switching frequencies in the 20KHz-50KHz ranges
so as to replace the traditional line-frequency transformer type welding machines. Thus, machines are
characterized with portability, small size, lightweight, low energy consumption and noise, etc.
GRAND TIG 200 DC has excellent performance: constant current output makes welding arc more
stable; fast dynamic response speed reduces the impact from the arc length fluctuation to the current;
accurate stepless current adjustment and pre-setting function. There are also some automatic
protection functions for under voltage, over current, over heat, etc. inside the welder, when the
problems listed before occurred, the alarm light on the front panel is on and at the same time the
output current will be cut off. It can self-protect, prolong the usefull life, greatly improved the reliability
and practicality of the welding machine.
The parameters of the machine on the front panel all can be adjusted continuously and steplessly,
such as welding current, down slope time and post flow time etc. When welding, it takes high
frequency and high voltage for arc igniting to ensure the success ratio of igniting arc.
This machine has wide range of applications. Given its small size, light weight, easy and flexible
operation, it can be used in various kinds of environment, such as working aloft, field work, interior
decoration, etc.
TIG series of welding machines is suitable for all positions welding for various plates made of stainless
steel, carbon steel, alloyed steel, titanium, magnesium, cuprum, etc, which is also applied to pipe
installment, mould mend, petrochemical, architecture decoration, car repair, bicycle, handicraft and
common manufacture.
2.4
Duty cycle
and
Over-heat
The letter “X” stands for Duty Cycle, which is defined as the portion of the time a welding machine
can weld continuously with it’s rated output current within a certain time cycle (10 minutes).
The relation between the duty cycle “X” and the output welding current “I” is shown as the right figure.
If the welding machine is overheating, the IGBT over-heat protection sensing will send a signal to the
welding machine control unit to cut the output welding current OFF and light the over-heat pilot lamp
on the front panel. In that case, the machine should not be welding for 10-15 minutes to cool down
with the fanrunning. When operating the machine again, the welding output current or the duty cycle
should be reduced.
Relation of welding current and
duty
cycle for
GRAND TIG 200 DC
