I did this when I got my first C7000. It came with 3 phase, but 3 phase was unavailable in my facility.
I tried using Phase Converters, and found that converters will only emulate 2/3 phases. Ergo only powering 2 of the 3 PSUs at a time. High Amperage Converters are VERY expensive and not worth the trouble and Mine kept tripping every time it did a boot cycle.
The 3 Phase Backplane has 2 Lines, A and B
Line A connects to PSUs 1 2 and 3, Line B connects to PSUs 4, 5 and 6. Depending on your power setup standalone/redundant/PSredundant you will need to place your 2 or 3 PSUs in the correct slots.
Each line has 4 wires. Common, Phase 1, Phase 2, and Phase 3. with each PSU getting 1 Phase and a common connected to it. Ex. PSU1 has Common and Phase 1, PSU2 has Common and Phase 2, PSU 3 has Common and Phase 3. They are DIRECTLY wired to the plug that your PSU plugs into, the backplane has no circuitry or regulators in between.
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Now that I have the Above explaination out of the way (I hope you understand it), Let me tell you a better way of going about it. (And the way I went eventually, but should have done from the beginning which would have saved me a ton of time/money/headache)
I got a new HP Power Module for Single Phase for like 50$ on Ebay that was designed for single phase. Each PSU has built in circuitry for both 3 Phase and 1 Phase. There is no need to change anything on the PSU itself and I did not have to configure or change anything on the Chassis Either (Im using a Gen3 C7000 Chassis). I have read other users who performed this task had to make configuration changes, but I assume that is because they had earlier generation chassis as I never had to go through this process. (You can tell which Generation Chassis you have based on the model #)
The way you tell the difference between 3 Phase 1 Phase Power Modules, is 3 Phase has 2 Hardwired L6-30 Cables coming out of it, while the 1 Phase, has 6 C19 Ports, intended to connect to a PDU. You cannot connect 1 C19 Cable to power multiple PSUs. Not only is it not safe, you will trip a breaker (hopefully) or slag your wires and start a fire.
Most C19 PDUs only have 3-4 Ports in them, and If you're looking to do N+N or N+1, you will need to put them on different PDUs and different lines to take advantage of the redundancy options. It will work, but wont help you at all if your Line is the fault and not the PSUs.
Also, what you really need is a PDU, not a power strip like the ones shown there. PDUs dont have to cost a lot, but the nicer PDUs have a lot of features that are useful like monitoring and remote shutdown of ports.