CNC ELECTRONICS Power Supply

[JAZZCNC]

I have found that the [FONT=arial]Leadshine DM856 CNC Driver Digital Hybrid Stepper Drive 80VDC/5.6A driver would be the best one for the job as it would allow me to run the stepper motors very fast.

When you say "very fast" what speed are thinking you'll get.? . . . . . Steppers in general don't spin very fast or should say are not much use spinning very fast. Much above 800-1000rpm and they lose fair amount of torque which drops off to nothing very quickly above 1200-1500rpm and at 1500-2000rpm there's next to nothing left.
Speed you get from steppers is mostly down to voltage so is proportional to the voltage provided to the drives and why Eddy current suggested 70vdc but there are limits and for these motors 70Vdc is close to the Max not the minimum. Running at 70vdc is considered working above the design threshold but in practice they handle this no problem and are reliable but going higher can produce excess motor heating which will shorten there life.

Also Be aware that Steppers produce Back EMF so are effectively dynamos when deaccelerating so you need a safety margin between voltage supplied to the drives/motors and the drives maximum voltage rating. Now how large a margin is slightly affected by the type of supply you use and it's for this reason why Unregulated Toroidal supplies are best because they absorb back EMF better thru there capacitors. So if using Toroidal setup you can effectively run closer to the drives Max voltage limit
Now That said even with Toroidal PSU the Maximum voltage I'd run is 75V on 80Vdc drives and for best balance of speed/motor heating and drive/motor life expectancy then I would run that at 70Vdc which is what I consider there MAX sensible working voltage. They will run higher but you'll kill them quicker.

Regards the drives then the DM856 are good drives but because your going to slave 2 motors to one axis then I recommend you go for the better EM806 or AM882 as they have stall detect and fault output which you can use to E-stop the machine if one motors stalls and the other doesn't which if your wanting high motor speeds there is a high probabilty will happen.!
I'll just point out that if your wanting high traverse speeds Ie Rapid speeds or cutting speeds then the correct way to achieve this is by selecting the correct linear setup Ie: screw pitch etc not soley using motor speed. Motors give a certain amount of torque on a RPM curve so matcing the screw pitch to give the speeds required at certain RPM/Torque is the way to do it not just find fast spinning motors.

[thorphar]

Thank you for the information. I am going to use 16x4 or 20x4 leadscrews so I should be able to get the speeds i want. I have found the AM882 drivers here (http://www.aliexpress.com/item/New-L...570168083.html) Would you agree with getting these ones. I will aim to make a 70vdc linear power supply with soft start. As i mentioned above and am looking to use leadscrews for all the drive mechs, however i need to find some nuts. Does anyone know of a cheap source of leadscrew (Trap) nuts? Thank you so far

[JAZZCNC]

Thank you for the information. I am going to use 16x4 or 20x4 leadscrews so I should be able to get the speeds i want.

Why lead screw.? What speeds do you require and what you cutting.?

Those AM882 are fine but just be aware you'll have VAT to pay and customs/shipping handling charge so they won't work out much cheaper than buying from UK and you'll have piece of mind can return to UK supplier. I find drives and BOB's are the one thing worth buying in UK even thou made in China as they are what give the most hassle or easily damaged by wiring wrong.

[Boyan Silyavski]

Most people here on the forum agree it seems that 1610 is perfect for all axis and 1605 for the Z. Forget about lead screws. yes, thats the motor that goes super well with AM882. I bought all from Zapp. Yes, you need 4 drives. The toroidal transformer i bought from ebay from Germany and from china the rectifier and the capacitors, is called by chinese a regulator.