Hi,

In other thread i saw that 48v can be "too much" to half coil. Is that true? If I undertand you correctly, as much voltage the better an the driver will limit accordingly.
No, 48V is not too much, it maybe enough for the speed you wish to drive your motors but its not too much. The driver limits the current so it doesn't really matter what voltage
the supply is the driver will limit the current anyway.

I use Vexta 5 phase steppers and matching Vexta drivers. The driver doesn't require a power supply, you wire it direct to the 230VAC supply. The voltage it applies
to the motors is a little over 150VDC! It sure make the motor sit up and take notice!

The datasheet of these motor in some sites indicates "4 phase motor" other "2 phase".
I think that refers to the wiring combination that has 8 wires, that is four coils. Two coils on in the same magnetic limb. Your 6 wire motor has identical coils just that
the two coils are joined together already at the center tap.

The current indicates 3A/phase. These 3A are for the full coil or half coil? If I set to full coil i need to config the driver to 3A and for half coil 3*1.414= 4.2A?
I suspect that specification refers to the maximum current in any one coil. So 3A through two coils in series. If you powered just one coil I think it prudent not to go above
3A because it will overheat, Admittedly the other coil on the same limb wont be getting hot because it has no current in it and overall the motor will be a bit cooler but to force
more through one coil may be asking for trouble.

Even at 3A you may find the steppers getting very hot.

As an example my Vexta 5 phase steppers are rated to 1.4A per phase. They go really well but get hotter than I like and so I have them dialed back to 1A per
phase. No doubt I lose a little torque but I can still run them to 2400 rpm without losing steps and staying under 500C. The steppers are mated to 10:1
low lash (<2 arc min) planetary gearboxes so the thrust they can exert on an axis is is over 4500N (450kg force), plenty!!!

Craig