Is this the same way how the expensive cutters work? Or are there some differences?
There are differences, quite a lot actually:
-High Voltage start uses a transformer at 50 or 60 Hz to raise the voltage to over 2000V, a huge resistor to dump some of the power and is wired directly to the electrode on one side and to the nozzle on the other side, also there is a RC filter to protect the rectifier from destruction at every arc start. Highly reliable, causes plenty of interference, especially as the nozzle/electrode get black inside and the arc is harder to start.
-High Voltage / High Frequency start uses a smaller high frequency (usually over 20 kHz) transformer and switching electronics on the primary side that creates 15000V through a sparc gap and another winding on a ferite core to witch the main electrode wire is also wound with the other side going to the nozzle, also has RC filters to protect rectifiers and a dumping resistor. Very reliable, causes huge amounts of interference, less sensitive to electrode/nozzle getting all black inside.
-Blow back start uses a spring loaded electrode that gets pushed back when the air is turned on while at the same time lets 3 to 5A of current through the electrode to the nozzle, so when the electrode retracts the sparc is created at what point the full cutting power is released. Pretty reliable, costs a lot in electrodes as they fail much faster due to current passing through a spring, less interference than both of the above.
-Scratch start uses ... well scratching the nozzle to the material to create a sparc, so it has nothing that the above machines have. Not sure about wiring as i never used one. Most probably creates more interference than BlowBack, but less than other two above.
