The specs state that it's operable down to 208V in 3-phase mode. I think a lot of people here are wondering how much the power output of the amp is de-rated at that supply voltage. Or perhaps it can still reach full power, but with a lower duty cycle?
(Quite familiar with your part of the world -- long ago, I taught English in Szekelyudvarhely, Romania.)
Since all of our amplifiers have regulated power supply and intermediate energy storage bank (capacitors) if your average output power does not exceed average charging power ( -minus energy conversion losses , few percent) the peak power is maintained.
Even on 85Vac single phase you could pull out the peak power but of course with very low duty cycle only.
The sustained power is always limited by the charging capability of power supply and available AC line current.
We have also user programmable line current limiter implemented in the 3PHASE and XE-U series amplifiers, which is a quiet handy feature if you need to operate on limited resources.
If you have 208V line-to-line in 3 phase mode the sustained charging power of the 3PHASE-40K would be limited around 14KW which may be adequate for many type of musics.
Congrats on your power amp. I understand the 1 space thing, It's because you can. I recall struggling to get 1 kW in 1U years ago.
I do have a few questions, while some may be related to imprecise language.
1. "high" power factor. By this do you mean it looks like a purely resistive load and current draw is spread across the entire mains waveform ala PFC (power factor correction) ? 3 times the work for 3 phase.
1. High power factor means that the consumed current is proportional with the AC Voltage so the load looks resistive. The current draw spread across (almost) the entire mains cycle with little current distortion close to the zero crossing points.
The most important is that horrible current peaks of typical "peak-rectification" is eliminated and can pull out the maximum power from the AC line without tripping circuit breakers. It is not a new thing most of other good high-powered amplifiers have this feature.
2. "Soft switching" is a term in power electronics reflecting the commutation strategy of a switching converter. It has been invented to eliminate the basic problems caused by "hard switching". All the problems originated from the imperfection of power switches and limitations of physical realization of the converter like layout, parasitics capacitances, stray inductances.
So the problem is that hard switched converter at this power level would have been limited bellow ~92-94% best efficiency even with the fastest & expensive like gold devices. Another thing is that too sharp transitions of the LARGE commutating currents would cause unmanageable level of Voltage transients on the stray inductances, increase EMI and affecting reliability together the output sound quality. The solution looks simple but it is not : I have reduced sharpness of commutating currents to load independent safe, fixed values + eliminated excessive losses of switching device by shifting Voltage/current curves in time during transitions.
This method is also used in our larger XE-U/XD-U amps, not only the 3PHASE.
3. There is a curve of each capacitor technology which Voltage level stores its maximum energy vs. volume. Fortunately the best range of the type of capacitor what we have and actual rail voltages are pretty close to each other...
4. Hard to determine the recycled energy, it all depends on the actual load, waveforms even the room where the speakers installed.
One time I have tested a reflex box with specific waveforms and surprised how the electrical characteristics of the box was affected by its physical arrangement to the environment, how close or what position to the wall, etc.. However if you see carefully the speaker not only a resistor but a lot complex active load there are some circuitry tricks, especially in the feedback of the amp to improve its ability to recycle reactive energy.