Quote Originally Posted by njhussey View Post
Well I used the first one you mentioned, i.e. double the total amps for the 3 motors. I'm sure someone like Irving2008 will be able to tell you far more accurately! :)
I think to an extent it's the more the merrier!
For my 3N.m motors it's 4.2A in bipolar parallel. [bold]You need 66% of the total peak current.[/bold] So three motors, that's 4.2*3*0.66=8.3A. I used a 500VA toroidal transformer, so 10amps. The motors did work perfectly well with a 325VA toroid but I couldn't get quite as high feedrates. I think because the internal resistance of the power supply was too high.

So anyway with your motors in bipolar series it's 3*1.5*0.66=3A. Or in bipolar parallel twice that, but I don't think your driver board will cope with parallel.