Need some help please on understanding the max current for these M60STH88-3008DF stepper motors. We have a PM542 driver that allows different currents to be set. Having read various threads and reviewed the motor calcs spreadsheet I still don't understand how to get from from the motor datasheet voltage-current values to real world values. For example, with this M60... motor the data sheet values are:

Wiring mode: bipolar series we've wired like this
voltage: 5.46 v
current: 2.1 A
resistance: 2.6 ohms
Inductance: 12.8 mH
Holding torque: 3nm

Obviously V=IxR works for the figures above; but in the real world I'm using 43vDC.

So what's the max current I should be using given my 43v supply and why am I using 43v when the data sheet says 5.46v?

Thanks