The Dreaded X axis stepper error using UC400ETH and UCCNC !!!

[dazp1976]

Motors are NEMA23 381oz/in 3.5A Single Shaft Stepper Motor KL23H2100-35-4A, 0.9 degree.

Power supply is PS-10N68 - 1000W 68V Power Supply running 4 of the above steppers, ( two of the motors would have been on 50% current hold ) when the other motor stalled also.

Nema23 running on 68V???

[Neale]

Nema23 running on 68V???

Nothing wrong with that. Most of us run NEMA23 size motors on about 68V. More volts, better performance. The motors are happy enough - mine have been running like that for about 7 years now. As long as your driver can take it (and again, that's why a lot of us use 80V drivers) there's no problem. Just tweak the max current settings on the drivers so that the motors don't overheat.

Somewhere there is a guideline formula (originally from the Gecko people, I believe) that suggests that around 50V is the optimum. Firstly, this is a guideline and not a hard-and-fast rule, and secondly, it's wrong anyway. Go by other people's experience!

[routercnc]

Agree. My steppers have been running at 68V on 80V drivers for several years too.

[dazp1976]

Agree. My steppers have been running at 68V on 80V drivers for several years too.

If I'd figured that out before, I'd have got the 570oz nema23 on 60v for the AMAT25 rather than the nema34 on 60v I have.

[Ger21]

If I'd figured that out before, I'd have got the 570oz nema23 on 60v for the AMAT25 rather than the nema34 on 60v I have.

It's not that simple.
A 450oz Nema 34 rated at 6 amps will usually easily outperform a 570oz Nema 23 rated at 5 amps.
Inductance plays a large role. And typically, smaller nema 34 low inductance motors can spin much faster than large Nema 23 motors.

[m_c]

It's not that simple.
A 450oz Nema 34 rated at 6 amps will usually easily outperform a 570oz Nema 23 rated at 5 amps.
Inductance plays a large role. And typically, smaller nema 34 low inductance motors can spin much faster than large Nema 23 motors.

Ger, I think you got your motor sizes mixed up there...

[JAZZCNC]

If I'd figured that out before, I'd have got the 570oz nema23 on 60v for the AMAT25 rather than the nema34 on 60v I have.

Horses for courses and You've got the right motors and voltage for that machine. Routers are a different animal so extra torque higher up speed curve helps.

[Clive S]

Horses for courses and You've got the right motors and voltage for that machine. Routers are a different animal so extra torque higher up speed curve helps.

Bloody hell Dean where have you been Nice to see you back

[JAZZCNC]

Bloody hell Dean where have you been Nice to see you back

Got to get back on the horse some time Clive.

[dazp1976]

Horses for courses and You've got the right motors and voltage for that machine. Routers are a different animal so extra torque higher up speed curve helps.

They don't give the speed I was hoping for but that may be down to the resonance I seem to get. It won't help. The inductance for them shows 4.1.
Looking at curves though the torque is equal between the 23 & 34 at 400rpm and over.
The 34 do however give very good acceleration so it's not all bad.
Spindle rpm will likely only allow 600mm/min anyway with 8mm 3flute.

Still an unfinished project.
The machine is more or less built, oil system is in, enclosure has minor snagging issues. Really I just need to finish the coolant system and I'm ready for first chips.