Losing steps/position, again

[JAZZCNC]

Steppers are generally all rated 2-3Vdc yes?. So if said nema 17 / 23 or 34 (2-3Vdc) were put on the same driver why would I only blow the 17? (unless I didn't change the current output).

I didn't say it would blow it up, I said it would destroy them and this is true. They couldn't handle the heat and that would kill them eventually depending on voltage.

Also inductance. There are Nema 34's out there that are abysmal running on 60V supplies and ideally need at least 120Vdc to work reliably.

Also there are now drivers on the market with direct 240Vac input connections so no need for psu's anyway. These are aimed at nema17-23 size. Why would these not burn them up either?

You'll find that many of the drives that use 240Vac won't run small motors for the same reason I mentioned before, most don't even limit current below 5a. The drives you speak of which use AC voltage and can run Nema 17/23 use Low AC voltage which you transform down from 230Vac and that gets rectified to DC in the drive.

I fit 230 Vac drives all the time and I can tell you that if I fitted those little motors or nema 17 motors to the drives they would be fried within hours. Even with small (4nm) Nema 34 motors you have to be very careful and make sure you limit current correctly because current it proportional to Voltage and you cannot limit the voltage so they get hot.
This is physics it's not me making shit up and just because you haven't experienced it doesn't mean your correct it what your saying. Unless you know it to be true then I suggest you STFU because it's hazardous to components life and even dangerous in some circumstances.

I and many others use 60Vdc at least using larger 34 size drivers to run nema17 & 23 size motors. Even that goes against the grain and it's worked for years.

No it's doesn't go against the grain and it's perfectly acceptable because the voltage is much lower and the motors can handle it. Again physics comes into play and there is an ideal voltage where motors run with-in safe tolerances, most people running more than 60vdc with NEMA 17/23 motors are running past the motor's ideal voltage but only just so it's not a problem. Think of it like overclocking a PC, it works but will shorten the PC's life unless it's cooled better, same shit here.! . . . Running higher than ideal voltages your actually shortening the motors life but who cares because it's going to take years if only 10-20v over but double the rated voltage or more and it won't take long. (unless cooled massively)