Hi. will share my knowlage (can be wrong

(PLESE CORRECT if You find uapproproite advice)
RST is surely 3 phase 200 - 220v ("American")....it mean 220 v between phase (f.e. R and S).
In my Brother TC-225 it comes from huge transformer....And I think...after transformer it's galvanicaly insulated from PE???
If You connect 380v it will be badabum:( DON'T TRY!
Usually servopach use 2 different power source:
- one for "Control circuit" abou 50 Wh,
- second - "motor power" to drive motor abou 4KWh
Usually "control power" supplyed to servopack immidiatly after machine "main power on" (green button on panel). After that you can turn motor by hand and see resolver/ancoder responce on screen.
Usually "Motor power" supplyed to servopack by contactor if machine ready to start....no e-stop...and "power" button from UI pressed.
In You case RST is "motor power"
rs is 220v "control power"
My advice:
1......for begining... just connect single phase 220v (ground and L) to rs
2. connect interface cable (usually it's a separate fun story) and ensure that encoder woks
3. then tryconnect 220v to RS..... I think it will not work and goes to "UV" - UnderVoltage error
4. start thinking about 3 phase and transformer
good luck !