Ordered a motor today through Grainger. Noticed several motors on the same page listed for 570Volts. I've just never seen a 570V service before. Where are they used, who has them?

Typically, in the textile industry you will find the 600 volt systems.

They could possibly be for sale to Canada as well. They use 347/600 volt wye systems.

I've run across one system in 28 years & it was at a coal mine.

Maybe it's 575 volts. That's a standard nameplate rating for motors operating on 600V distribution--in the same way that 460V motors are intended for 480V systems {or 200V motors for 208V systems.}