Most MODERN power supplies automatically accept input from about 100 VAC to about 240 VAC with no "switching" needed.
Only older "transformer-input" type supplies needed the switch.
US outlets for 234VAC circuits are NORMALLY NEMA 6 series outlets (this is NOT the same as the common NEMA 5 outlet you see in most houses).
Cords for NEMA 6 to connect to standard power supply connections tend to be less common, and more expensive, than the very common NEMA 5 cords - there are quite a few folks that sell them though, check eBay, Amazon, Newegg for them.
The cord you have the link to IS the type you are looking for - but way expensive, and you don't really need a "heavy duty" version as you're pulling well under 10 AMPs to fully power a APW3++ at 234 volts.
The cord shown appears to be a NEMA 6-20 (20 amp) cord, you're more likely to want to use NEMA 6-15 cords and outlest (a NEMA 6-15 plug WILL plug into a NEMA 6-20 outlet, but not the other way around - like on NEMA 5 plugs/outlets the 20 amp version has one "T" type socket connector).
With some digging you should be able to find applicable cords in the under $10 range.
Thank you both for answering.
I wired in a new 30 AMP two pole circuit, and installed a NEMA 6-15 Outlet. Then got the proper cord cap (replacement end) and cut off the NEMA 5 end. I replaced the NEMA 5 end (standard in US 110 systems) with the NEMA 6-15 cord cap (end) for 240V applications...did nothing to the other end where it connects to the bitmain unit.
My new readings are as follows using a Fluke 87 Multimeter and a Yokogawa Clamp on Amp Meter.
Original arrangement the single black power wire at the circuit panel was drawing 12.7 amps at 121Volts...which equates to a total draw of 1537 watts!!!!
New arrangement... voltage measured 242Volts. Circuit drawing 5.7Amps, volts x amps = Watts 242 x 5.7 =1379 Watts.
This equates to a savings of about 158 Watts continuous. Everything (cord cap and cord) running cooler now too. I feel much better.
I'm amazed it even ran,
It hashed correctly but I'm sure it's much happier now with 240Volt power
Thanks again for the help.