[Nixx123]

Hi guys,
I am new on this forum and i registered because i need help with my CNC conversion. I am planing to convert my Sieg X2 mini mill to CNC, and i need your opinion about steper motors.
I am planing to use 2 NEMA 24 3Nm stepers for x and y axis and NEMA 34 4.6 Nm motor for z axis. They are connected to 2 3amp drivers and 1 6amp driver from BuildYourCNC.
So my first question is are these motors too small/large for this purpose and i would like to know which power supply to use with them since i don`t know how to calculate power consumption for these motors, i tried to calculate working voltage from drive current and coil resistance using Ohms law and then multiplying that with current to get power but i get ridiculously small values around 10W.
Also is it true that driver input voltage should be square root of motor inductance in milihenries multiplied by 32 because that voltage seems quite high, 72 volts for NEMA 34 motor i am using.

Thanks in advance ,
Niko

[Trotline]

Hi Niko! the voltage formula is for the ideal maximum performance of the stepper. They will run on lower voltages, but won't develop their maximum output until the voltage reaches that value. In practice, almost all machines run at much lower voltages, simply due to the cost of power supplies and drives. Have a look at Hossmachine Homepage, for a very well documented X2 build. Hoss has some threads on this forum that go into great detail on the build, and there are a number of others who can contribute their advice on motor selection. From what I've gathered, (I don't have one of these conversions), the NEMA 34 motor is probably not a great choice. Good luck, and have fun!

Luke

[kawazuki]

Most of these conversions run Nema 23's on all axis - mine uses 1.85Nm motors and I use a Gekko G540 drive / BOB box that is capped to 3.5A max output per motor so that governed my choice - mine worked out at max 50v and the power supply I built came out at 42-43v and 11A and runs the machine as fast as I need. Of course using ball screws helps cut down the friction and up the precision but its not watch making so +/- 0.1mm isn't that critical to me.

[Nixx123]

Well i think i will stick to 3Nm motors just because i am planing some modifications in future that will add weight to the machine so i think its better to have larger motors.Now i was looking for other types of breakout boards the other day and found planet cnc mk 3/4 controller which seems to have much more inputs and outputs than the breakout board from BuildYourCNC so what do you guys think about that board, also does that board support single block mode?