I have a question. I am buying a used Lincoln Invertec Power Wave 450. It s 3 Phase, Robotic machine, and according to Lincoln, they last made these in 1999. What I am wondering is, can this be converted to single phase like Dave Kamp did with the old Miller CP 250 ?
Thanks sincerely,
Barry
Hi Barry!
Well first... there's LOTS of questions that guys post about '3 phase to single phase'... change the name of the thread to reflect the make and model, and it'll help stand out, as it's more descriptive of your inquiry's content.
Now... I downloaded the manual, and wen to page 49 to look at the wiring diagram, and yes, it's hyroglyphic lego blocks, rather than a line image, so really can't get much of anything great...
That being said, it looks like an inverter-based machine to me... so...
inverters work in three stages- first, convert AC to DC. Second, convert DC to something else... Third- use that to make something else. In the case of inverter-based welders, you need to change high-current, high voltage AC into much higher current, but relatively lower voltage.
Typically, an inverter-based welding supply doesn't really 'need' three phase, but manufacturers design their machines to USE three phase, because they know that their power systems are three phase by historical nature, and putting a high single-phase load on a three phase distribution system is not 'nice' to the system.
Second note, is that many 'three phase' machines, are actually 'open delta' machines... two single-phase transformers... one tied from A to B, the other from A to C, but there's no connection between B to C. This results in a 'three phase' load, that's not really 'three phase', becuase the transformer core doesn't have the full triangle of current circulation. it is still, nonetheless, a three-phase balanced load.
Many of the machines I've been asked about, were actually 'open delta'... lots of the 250-350A Union Carbide, Airco, and similar machines were nothing more than two single-phase transformers tied at the hip. Converting 'em, was as simple as tying B to C, setting jumpers to 230, and putting one of the single-phase HOTs to the B-C connection, and the other to A. Duty cycle? no change. Output? No change... or perhaps a smidgen better (running 230v coils on 240v)
If this inverter machine is wired in open delta, and you were to have a schematic that'd allow you to get all the connections right (so that the controls were appropriately fed, I see no reason that it wouldn't run on single phase at full capacity and rated duty cycle, but it would absolutely positively require a good, legible schematic.
Actually, the first thing I'd probably do, is wire it to single phase across two of the three) and power it up, load it light, and see if it throws a fit. IF it has phase loss protection (spits out an error, etc), then I'd wire up a 1000v 1uf capacitor between the unused, and one of the hot legs, and see if it clears. it may be that the electronic controls are 'too smart' to allow it, in which case, it might even be challenged by the assymetry variances of an RPC.
And it may be that 8if you just plug it in as single, it'll get up and go.