EXT250 A/C questions

[performance]

Mike,
Perhaps it would be better to download the manual and look at the unit wiring schematics. Its not detailed circuit board schematics, but it covers the basics. The features and functions are microprocessor controlled largely and the inputs and panel are digital... No analog rheostats except on the foot pedal.

[Mike J]

Mike,
Perhaps it would be better to download the manual and look at the unit wiring schematics. Its not detailed circuit board schematics, but it covers the basics. The features and functions are microprocessor controlled largely and the inputs and panel are digital... No analog rheostats except on the foot pedal.

Oh man, now I feel like a dummy! You mean RTFM, right?

That is the beauty of these forums, thanks!

Cheers

Mike

[everlastsupport]

The unit is a digitally controlled solid state (inverter) welder. But it still uses a lot of analog on the welding side. But has a digital is the front end/control.

On the HF board. It is a flyback transformer, like a 15KHz Hosc circuit in a TV. It is a lot higher freq than the welding features/frequencies, so it is HF compared to most (excluding the ATMEL mega's internal or external osc in the digital control). To an EE it would be a HV board not a HF board. In a welding circuit it is the HF spark gap to jump and start the arc transfer.

Hope that helps.

[jakeru]

Here is a post I made a while back regarding my Super200P's high frequency circuit design (turns out it was on another forum, but relevant to what we're discussing here):
http://weldingweb.com/showpost.php?p=342080&postcount=3

In summary, it's a "tesla coil" circuit.

As for the 250EXT, I would guess based on the picture in this thread, that it may use a similar "tesla coil" circuit as well. (Those two blue, cylindrical capacitors look just like the ones in my Super200P.) The EXT's spark gap conductors are dramatically different (possibly improved durability tungsten?) compared to the copper material spark gap found on nearly all other imported inverter machines with high frequency arc starting.