Did a bunch of Tanning Bed stuff between 1990 and 1993, so please bare with me if I am not up with the current stuff!
All the Beds that used Fluorescent Lamps (typical arays of T12 Lamps, with Beryllium added) were intended to be connected to 120/240 Volt single phase 3 wire circuits.
Although they were used in buildings having 208Y/120V 3Ø 4 Wire Systems, they still required a 3 Wire circuit - as the Ballasts were 120 Volt rated, so were the fans and control equipment (contactors, etc.).
These Beds had one circuit driving the top section, and the other driving the bottom section.
Never saw any Fluorescent Lamp type Bed which was designed to be driven by a 240 Volt 2 Wire Circuit.
I did, however, connect several "High Intensity Beds", which were designed to be connected to 200 - 250 Volt 3Ø 3 Wire Circuits.
These did not use Fluorescent Lamps (T12), but instead use High Wattage Mercury Vapor HID Lamps.
The Ballasting of these Lamps was done via individual Autotransformers, with a variety of input Voltage taps.
The "Common Wish" of the Clients I dealt with was to have a little higher Voltage at the Bed, so the Lamps were driven as high as possible.
Best bet is to read the tolerances listed on the Ballasts themselves, test the Nominal Voltage at the Beds' Outlet (do so during peak times and non-peak times), and apply Voltage correcting methods as needed.
If these Beds are indeed using 120 Volt Ballastry, requiring a 3 wire circuit, then you will need to use two Transformers to boost / buck Voltage - _UNLESS_ you drive a separate Panelboard from a Wye connected Autotransformer system (Boosting/Bucking arrangement) and use circuitry from it for these Beds.
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!