ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades What is the meaning of "R-S-T" in 3-phase system?

I'm trying to find the reason the 3 phases are named "R-S-T" in a unit from Taiwan. Is it just something someone came up with like "A-B-C" or could it be an acronym for something?
I've found that it's used in various places like Sweden and Korea. But Google doesn't come up with much else. Pointing me to the appropriate standard(s) would be super.
Thanks much.
Paul