Advice on these steppers -Nema 24 Stepper Motor 24HS34-3008D

[CharlieRam]

Hello All, I'm back again and still haven't finished my machine! Anyway, I'm just looking to purchase the steppers and came across these:-

https://www.ebay.co.uk/itm/Dual-Shaf...QAAOSwHu5b5ADz

They look almost identical spec to the 3.1Nm ones currently on CNC4You that I saw recommended elsewhere, well all apart from the Voltage?
https://www.cnc4you.co.uk/Stepper-Mo...YGH301B-Nema23

It says voltage of 24-48 volts in the spec but my Toroidal power supply should be around 70v when I actually assemble it. Are they a different motor and therefore not suitable?

Cheers,

Charlie

[m_c]

Going by the key spec (current and inductance), they are pretty much identical motors.
However I'd say 70V is too high. The recommended max voltage is 32 * SQRT(L) (L is inductance), which puts the recommended max voltage around 57VDC when running with parallel/unipolar wiring.

A higher voltage won't have much effect at lower speeds, however if you're running at higher speeds, overheating is likely to become an issue if running at the rated current.

[CharlieRam]

Thanks for the reply, I probably should of said I plan on connecting them in series so the max voltage works out at 114v given the above formula unless there is a reason not to connect in series🤔

Cheers

Charlie

[m_c]

You'll get better performance for any given voltage using parallel.

Inductance is the killer of performance, which is why you normally want steppers with as low an inductance as possible.

[CharlieRam]

Am I looking at this all wrong? I'm thinking of getting the EM806 or AM882 80v drivers, I have a 2 x 25v toroidal transformer and 4700mf 100v caps and rectifier to build the PSU which should deliver 68v, I am scratching my head at what stepper motors I should get to match the Power supply....if those 3.1Nm steppers only require 57v would I be better to go for 50v drivers and a smaller PSU?

[Clive S]

Am I looking at this all wrong? I'm thinking of getting the EM806 or AM882 80v drivers, I have a 2 x 25v toroidal transformer and 4700mf 100v caps and rectifier to build the PSU which should deliver 68v, I am scratching my head at what stepper motors I should get to match the Power supply....if those 3.1Nm steppers only require 57v would I be better to go for 50v drivers and a smaller PSU?

Personally I would go with the 68V p/s with the drives above or https://www.ebay.co.uk/itm/2DM860H-2...frcectupt=true

There are plenty of people using this setup without problems

[CharlieRam]

Clive, Are you saying the 57v rated Steppers will be fine with the 68V PSU and either of those drivers? I am sure this is what people have used in the past but m_c says the voltage is too high! I'm a little confused now.

Personally I would go with the 68V p/s with the drives above or https://www.ebay.co.uk/itm/2DM860H-2...frcectupt=true

There are plenty of people using this setup without problems

I saw those drives but was a little unsure....have many people used them? It doesn't look like it has stall detection although I do understand that if the motor has stalled the job will be wrong even with stall detect.

[Voicecoil]

It's worth doing the sums and working out exactly what voltage you need - for some motors 50V would be fine, for others a big hindrance. Thankfully, @Irving2008 has put it all into a handy-dandy spreadsheet which ties together all the variables (apart from using pulleys/gears with a non 1:1 ratio) for which he deserves a beer - go looky here:

http://www.mycncuk.com/threads/1524-...tor+calculator

[CharlieRam]

This is part of my problem...the spreadsheet says the motor has a good margin but will it be ok on a 70v power supply??

[Clive S]

Clive, Are you saying the 57v rated Steppers will be fine with the 68V PSU and either of those drivers? I am sure this is what people have used in the past but m_c says the voltage is too high! I'm a little confused now.

I have always used 68 V with no troubles, everybody has their own opinion so you have to make your own mind up.

I saw those drives but was a little unsure....have many people used them? It doesn't look like it has stall detection although I do understand that if the motor has stalled the job will be wrong even with stall detect.

I found them about 2 years ago and have used about 8 of them Dean (Jazzcnc) I think has used more than 12. re the stall detect you are correct they don't have it. But the AM882 and EM806 does have it but if I remember correctly it only kicks in at about 300 rpm.


As m_c has stated go with a parallel setup.