The working principle of GRAND CUT 60 is shown as the following figure.
Three-phase 380V line frequency (50/60 Hz) AC is rectified into DC, then it is
converted to medium frequency AC (about 20 KHz) by inverter device
(discrete 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 stably. Meanwhile, the
cutting current parameter can be adjusted continuously and steplessly to meet
with the requirements of cutting craft.
2.3
Working
Principle
Rectify
Inverter
Medium
frequency
transformer
Medium
frequency
rectify
Hall device
Current positive-
feedback control
Three-phase, AC
DC
AC
DC
380V
，
50Hz
AC
DC
The letter “X” stands for Duty Cycle, which is defined as the portion of the time an
air plasma cutting machine can cut continuously with it’s rated output current
within a certain time cycle (10 minutes). If the plasma cutter is overheating, the
IGBT over-heat protection sensing will send a signal to the plasma cutter control
unit to cut the output cutting current OFF and light the over-heat pilot lamp on the
front panel. In that case, the machine should not be cutting for 10-15 minutes to
cool down with the fan running. When operating the machine again, the cutting
output current or the duty cycle should be reduced.
2.4
Duty
cycle
and
Over-heat
