[ModMatters]

Hello everyone,
Glad to finally start my own CRP4848 CNC router build.
Got all the extrusions from Ahren at CNC router parts, everything looks good so far!

Motors & Electronics:
Bought a Nema34 set from longsmotor on eBay:

• 4 x 1232oz Nema 34 bipolar motors (3.08V, 5.6A, 0.55Ohm/phase, 8.4Nm (torque)
• 4 x DM860 stepper driver (7.8A, 256 Microsteps)
• 4 x 350W / 60V / 5.6A power supplies (don't ask why there are 4 of them??!! . Gonna get one to handle all motors.
• 1 x cheap breakout board that doesn't deserve to be called a breakout board basically.

My experience with electronics is still at the beginner stage, I would truly appreciate any advice from the many experts' on this forum!!
My inquiry is in regards to the power supply I need for my Nema 34 setup. I have done a bit of research and hopefully have calculated the V and amps needed correctly:

• Voltage required: 3.08 x 20 (need 10 to 20 times the voltage of the motor) = 61.6V
• Amps required: 5.6 x 4 x 0.66 = 14.8A. (Sum of all motors' amps times 4 times 2/3)

If my calculations are correct, I'll need a 60V power supply with at least 15A
Please correct me if I'm wrong.

Here's my question: should I get a 56V x 20Amps (KL5620) or go with 60V x 20Amps (KL6020) power supply to be safe? Or do I need even more powerful PS?
Here's the link to the supplies: Toroidal Power Supplies | Automation Technology Inc
The difference is significant to me in terms of size of the units - the 60V is much bigger, heavier (no clue the height, but probably much taller also!)
If 56V will be plenty for my application - I'll definitely like to go with that one rather.

Here are my next steps for the build:
- order for PMDX-126 Board and PMDX-107 (VFD spindle controller)
- order 220V air spindle
- order VFD (will probably go with the cheaper version to save money for now ...Huangyang VFD)
- still contemplating on whether I'll need the Smooth Stepper - not really sure the advantage besides the fact that I'll be able to use my laptop (and no need to printer cable)
- order the correct Power Supply (please help!:)

I will be posting pics and the process/updates of my next steps of my build in next post shortly!


Cheers,
- Dex

[LTHOMPS]

Since the power is not 100 clean you may get spikes and do damage to the steppers. I would go with the 56. Also, since youre already ordering from PMD just get their power rectifier and add your own toroid. This is what I done and it should come out cheaper.

[CYoung]

I assume you have already moved on from this post, but I dont know why you are so concerned between a 56V or 60 V power supply. All switch mode PS have noise and that is the purpose of the motor controller, to clean up the power and provide clean signals to the steppers. I old machine used a 36V PS and there were no issues. I am in process of building the PRO4848 right now and the PS from CNCRP is a 1KW 48V SMPS. I think you will have plenty of Voltage with either 56 or 60V.

[ger21]

For maximum performance from those motors, the voltage should be 32 x sq rt of the motors inductance rating. I'm guessing it's around 6mH, which works out to around 80V.

[CYoung]

80v is the top end operating range of the gecko drivers. I wouldn't want to push it that high.

Sent from my SCH-I535 using Tapatalk

[ModMatters]

Hey guys!! Thanks everyone for your responses and help!! Couldn't post for a while (safari issues with the Zone).
So I did end up buying the 56V ps and the thing is enormous! But it looks like it will fit in my enclosure.
I have also just received the following:
- PMDX-126 Board and PMDX-107 (VFD spindle controller) - really excited to hook these bad boys up!
- got the 220V air spindle
- got the VFD (.Huangyang ) - by the way - I've seen a lot of posts people saying there's no proper English documentation. They have seemed to have fixed this issue as mine cam with a nice English manual. I'll be working on wiring this thing this week.

Been a little held up with 220V wiring at my warehouse space...took 2 weeks and about a $1000!! to wire up 2 3-phase 220V / 30 Amp outlets. Now I realize that I should have had the 2nd outlet wired with single-phase...this will be for the Vac system...hope it's not too big of a job as I've spent way over the budget I planned for electric work. Anyway, the 2 outlets were just finished and I am going to start testing all the electronics this week. I've decided to hook up most if the electronics setup before proceeding with the build as I hear that's the easier one of the two.

Will post pics of some of the devices/electronics and parts this week.
I actually have a couple of photos of VFD, spindle and the power supply already...I'm going to try to post some in this post. Bear with me as I've never tried doing it through my ipad. Hopefully it will work.

Also - check out the weird indentations on the air spindle collet. It almost looks like it was butchered during manufacturing. How does someone send a collet looking like this?? Hopefully it was just the collet as that's a quick and easy replacement.

Thanks again for all the help!

-Dex

[alan_3301]

I wish you would have asked first before paying to get that 3 phase hooked up!
Single phase is fine for those vfd's. Oh well, I'm guessing the warehouse already had a 3 phase panel in it, you just got some outlets run?

The drill marks on the collet nut are for balancing, there is a eccentric ring inside the nut to help in removing the collet, which is the need for the balancing holes.

[Dan911]

Hey Dex,

I bought a similar 34 nema kit from Longmotors sometime ago and still sitting in there boxes. I had some trouble with losing steps or resonant issues. I'm just about ready for electronics on a build now, could u please LMK how your steppers work with the bigger PSU? Trying to decide if just get new steppers or try the bigger PSU. I also had to get the motor pulleys I purchased at cncrouterparts bored to 14mm. The shafts are bigger and longer. So you will have to cut the shaft of the stepper motor to work with cncrouterparts rack and pinion set-up. Heres the model # of stepper motors I purchased. 34hst9805-37B2

[ModMatters]

I wish you would have asked first before paying to get that 3 phase hooked up!
Single phase is fine for those vfd's. Oh well, I'm guessing the warehouse already had a 3 phase panel in it, you just got some outlets run?
The drill marks on the collet nut are for balancing, there is a eccentric ring inside the nut to help in removing the collet, which is the need for the balancing holes.

Thanks for clarification Alan! It never crossed my mind that there might be a reason for the drill marks as there were absolutely no symmetry in their placement. Will leave as is then.
The electricity job came out excellent...checking out right now. Will post pics shortly. Definitely didn't need 3 phase. How difficult is it to rewire the 3 phase to be a 1-phase? The VFD will be fine with the 3 phase outlet however the VAC system needs to have single phase 208V coming in - not sure what I should do here.

Hey Dex,

I bought a similar 34 nema kit from Longmotors sometime ago and still sitting in there boxes. I had some trouble with losing steps or resonant issues. I'm just about ready for electronics on a build now, could u please LMK how your steppers work with the bigger PSU? Trying to decide if just get new steppers or try the bigger PSU. I also had to get the motor pulleys I purchased at cncrouterparts bored to 14mm. The shafts are bigger and longer. So you will have to cut the shaft of the stepper motor to work with cncrouterparts rack and pinion set-up. Heres the model # of stepper motors I purchased. 34hst9805-37B2

Hey Dan,
I haven't had a chance to check the steppers for resonant issues. However - I also bought the PMDX-126 board - to give me more options for expansion, speed control and possibility of smoothstepper later. I've read your posts in regards to the issues with the Drivers/steppers from longsmotor...It seems like most people are suggesting getting the Geckos to take care of the resonance issues with these "wonderful" motors from China. I'm sure I'll have the same issue with the DM860s but I'll try and give it a shot. I was originally planning on getting the geckos for the motors but went over my budget by a lot already so I'll try them out before throwing another $500 - $600 on another set of 4 drives. Will post my results as soon as everything is hooked up and tested. Meantime, let us know if you get the Geckos and try it out with the motors. ....My motor part# is 34HS1456. Here's the item# on ebay by the way, I believe they're still listed: 200904596654
***You're absolutely right - a big inconvenience in getting the steppers elsewhere is the mismatch of the shaft sizing and CRP pulleys. Not looking forward to the adjustments there.

Thanks for your input guys,

-Dex

[Dan911]

I actually did the opposite, I purchased 34nema motors from cncrouterparts and worked flawless with the DM860 driver and BOB from China. That's why I was curious of your results with a higher voltage PSU. I went that route because I figured even if I got the Gecko driver and fixed the resonant issue I still wouldn't be able to get the full potential of the stepper because the voltage would be to dangerously close to the drivers limit.

Good luck,
Dan

[Dan911]

Sorry double posted