I get it. My PP manual is in the other shop so you answered the question I posted to them. Sounds like the simplest, cheapest, easiest for me to understand solution is adding a third 2 kva ACME to match the other two. Hit me long enough and I MAY catch on. Dave
Saw the JST post. Am I correct that your response is that the two transformers wired as your diagram are still isolation, just 56% of what three would provide ? Dave
They 'can be' all you need. Per several reminders, above, they have to be wired just right. That is not built-in obvious as it is on a packaged 3-Phase transformer.
Two transformers 'push off' the reference point against the third leg, much as the note above showed the Phase-Perfect had done. Leg to Leg is in balance.
This part is between the P-P and the transformer primary, so you are still at only 240 V delta. You can easily wire it safely, you aren't too concerned about which leg is close or not so close to Earth ground, a bit of proper conduit prevents worry.
That 57% is for Wye, generally safer, but which you will NOT have, anywhere, so it does not enter THIS picture at all.
On the secondary side, you now WILL have 600 V above EARTH, "PE", machinery frame, the floor, some other machine's just-severed power-cord, the puddle of water that leaked in during the storm...whatever.
I live where air-mass thunderstorms are 'standard issue', so Jerry's point about spikes when already at 600 V is 'standard issue' as well, not theory. Ate another Dell laptop PSU just last week ,so is bad enough on 240 V, and why I won't even go near 480 V, let alone 600 V.
Other way around here. I tend to use 600 V-class switchgear on 240 V for the extra safety margin.
Waste of money and a needless risk to run higher voltages when motors are so easy to change.
For a person with a machine-shop it isn't hard to fab adapters, mounts, shaft couplers, and such. Not as if all you had for tools was a hairpin and a butterknife.