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    Default Low Voltage vs High Voltage Stepper motors?

    Ok so after thinking I was ready to order my electronics, which were this:

    - Arduino with CNC Shield and A4988 Motor Drivers
    - 12v 30A power supply
    - What I thought were 12v 270 oz-in Stepper motors

    The real confusion lies in the stepper motors. I assumed they were 12v when I took a quick glance at the page here:

    Nema 23 Stepper Motor 1.26Nm 2A 4-wires 6.35mm Shaft DIY CNC Router Mill XP9 | eBay

    But when I was about to purchase, they were 3V 3A, and I dont understand how 3V would get me 270 oz-in of torque.

    So my question is, is there something particular that low voltage stepper motors are bad at, or should i just use them. Also, since I purchased a 12v power supply, how do I get the drivers to run at 3v, is that a setting in GRBL I just change or am I missing something?

    Thanks in advance!

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    Default Re: Low Voltage vs High Voltage Stepper motors?

    The voltage rating on the motor has nothing to do with how much voltage you use to drive them. The rating on the motor is how much constant DC voltage can be applied without exceeding the current rating. However the stepper drives are chopper drives, so the DC voltage/current is not constant. Bottom line is ignore the voltage rating on the motor.



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    Thank you for the quick reply,

    Sooo basically from what I understand, you can set the voltage to something high, in my case im using 12v, and the drivers will handle the rest? Do you recommend more than 12v, because I already purchased a 12v power supply

    Thanks!



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    If you look at the Gecko drive "step motor basics guide" it gives the following information:

    http://www.geckodrive.com/step-motor-basics

    "The voltage of your power supply is entirely dependent on the inductance rating of your motor, which we learned is translatable to the number of turns of wire in the stator. Every motor model will have a different inductance rating and will therefore have a different maximum voltage. To figure out what the maximum power supply voltage should be, use the following formula with the motor’s inductance in millihenries (mH) used for the L value."

    32 *sqroot(L) = VMAX

    For the link you posted

    Nema 23 Stepper Motor 1.26Nm 2A 4-wires 6.35mm Shaft DIY CNC Router Mill XP9 | eBay

    that's 5.0 mH, so power supply max voltage should be 32*sqroot(5) = 71 Volts

    So 12 Volts will not work for you.

    Whether 48 Volts will be enough, or you need 60Volts, or what happens if you used an 80 Volt, well, perhaps 109jb or someone else can explain that, but I can tell you that 12 Volts just won't work out for you.

    You should look for some torque vs speed graphs for the motors, usually they list the voltage of the power supply used for the tests.



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    Im now looking at this:

    US Ship Nema 23 Stepper Motor w/ Toshiba Driver TB6600 kit 1.9 N.m 269 oz.in | eBay

    It is same oz-in, but the mH is 3.4 (55V max) so I can use a lower voltage, and it comes with controller, it seems like a good deal to me and I can buy a 36v power supply and run it, and I think this is way better than what I currently have. Anyone think this is a good idea?



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    The TB6600 drivers are known to have circuit design issues. There is a thread here all about it. The Toshiba TB6600 chip isn't the problem, but rather the circuit it is built into and many of them have design flaws that can cause problems. I have several of the ones like in the picture I have attached and they work fine, but they also have circuit design flaws.In my case the design flaws found only affect the maximum current and limit it to about 3.1A. In my case I only needed 2.8A, so they are just fine.

    As for voltage, The motors will like the higher voltage, but you don't necessarily have to use the ideal calculated voltage if you don't need that level of performance. On the motors I am using with the TB6600, they are pretty high inductance with a calculated ideal voltage of 80V and I run them at 40V. They have all the performance I need in my application so in this case 40V is fine.

    Low Voltage vs High Voltage Stepper motors?-tb6600-jpg



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    Since this thread is in the 3d printer forum, I wonder just how much speed/torque/performance you really need. If using belt drive, the RPM will be low even for fast moves and you will still be in the high torque range even if the voltage isn't as high as it could be. A description of your machine would help.



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    Oh I didnt notice this was 3D Printer forum, my bad.

    This is actually for my DIY CNC Router for cutting aluminum. Here is the CAD for it, you will likely notice the design as it is similar to others around here;

    https://grabcad.com/library/custom-cnc-router-v2-1

    I wanted motors with atleast 200oz-in, which the ones I linked below have, and come with the drivers. I think ill go with them and then hook the controllers up to an arduino and run GRBL, does that sound like a good plan? I really hope so :P



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    Quote Originally Posted by Brian_M View Post
    I wanted motors with atleast 200oz-in
    How did you come up with this number?

    Quote Originally Posted by Brian_M View Post
    This is actually for my DIY CNC Router for cutting aluminum.
    I just don't see this working out well for you. The machine design looks sturdy enough, but 200 oz-in.....that's low. Seriously, what kind of performance do you want to achieve? You never did answer before when I asked about what lead of ballscrew and what your desires were for top speed and acceleration. And you need a bit more force available for cutting aluminum, albeit I don't think you plan on cutting it too aggressively? Regardless, why build a nice machine and underpower it?

    I realize you may be on a tight budget, so am i for my build, and the CAD dollar doesn't help, but shop around a bit.

    Look, there's a no reserve auction going on here for some 435 oz in motors and drivers:

    【US ship&Free ship】4Axis Nema 23 Stepper Motor435oz 4.2A 115mm length &Driver 2 | eBay

    I'm not saying you should buy that one, only that there are other options. Also, I wouldn't buy anything without first seeing a torque vs speed graph for it and doing some basic calculations.

    And don't worry if you don't get that one, another one will pop up when it finishes, I bet you. During the past week on Ebay, there have been several. Not sure what's going on, but I did win one this morning for three 1232 oz in Nema 34's for 71 USD including shipping. I haven't done the math for your build, but I do suspect that you are not going to be at all happy with 200 oz in motors.



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    I'll be honest, the answer to alot of your questions are... im not sure.

    I came up with 200 oz-in after doing some searches and seeing what others used in their machines, and I saw alot of <100oz-in, and they were cutting aluminum just fine, so it was my best guess of what I needed. I am trying to make my machine work to cut aluminum, thats my only goal, im not particular about speed, not even too picky on accuracy, (but im trying for within 5 thou). Im sure you know im trying to keep on a very tight budget, and im sort of trying to scrape by on what will get me up and running, and then upgrade to max potential of the machine later. I usually only buy from buy it nows, because in my experience they are cheaper, although ill start taking deeper looks now, thank you! That does look like a great deal, ill see if I can snag it tomorrow. I think something to note, Im using 2 motors for the x axis, which i think helps with the low oz-in because thats obviously the heaviest part of the machine, whereas I see these 425ozin with only 1 on all axis, i think that something that would be important, but nonetheless ill keep on the lookout for better deals.

    From what i've heard, you want alright speed to keep up with chips when cutting aluminum (Could be wrong here), and I was going to go with the 1605 ballscrews which seem very standard on most machines, so I generally assumed it would work for me, and I found it at a good price.

    Im really thankful for your help, im sure its apparent im really new to this, ofcourse the learning curve is always hard.



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    I did a little looking. I didn't find a graph for the Nema23 motors in the previous link. I did find a graph for a similar one.

    Low Voltage vs High Voltage Stepper motors?-23hs9430-jpg

    If you want a graph you can go to the Long's motor website, depending on who is there for the online help, and if they speak english, you can ask for the graphs for whatever motor you want if you give them the model number. I've done this before, it worked out fine, I tried it today, and the person at the other end responded only in Chinese. You can also send them a request for the graphs you want via email if no one is online.

    So I interpreted that graph to be 400 pulses per revolution. Normal is 200 steps per rev, and it says half stepping. So I divided by 400 and then multiplied by 60 to get RPM. Also, it said 30V power supply, but if you look at the mH of that motor you can push it higher for better performance.

    Here's what my math tells me:
    Low Voltage vs High Voltage Stepper motors?-brian_m-jpg

    You might need to download that then zoom in. Not liable for errors in math if they exist! But I'm pretty sure my math is close. It doesn't include preload or bearing drag and assumes 90% efficiency.

    So yes, you could use less powerful motors and run at the slower speeds with 5mm lead, should be OK, but painfully slow in my opinion. It also depends on how the specific motors you use are at higher speeds. The one I found isn't very fast.

    In my opinion you should do yourself a favor and get the 10mm lead ballscrews. I also made some bold assumptions and probably over estimated some of your weights, as you have not told me what they are. Yes, you could use some less powerful motors for the dual gantry drive. But if the best deal is found buying them all as a package at auction, then there's no point. Shop around. Also check kijiji.

    I hope this was helpful.



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    Quote Originally Posted by Brian_M View Post
    Ok so after thinking I was ready to order my electronics, which were this:

    - Arduino with CNC Shield and A4988 Motor Drivers
    - 12v 30A power supply
    - What I thought were 12v 270 oz-in Stepper motors

    The real confusion lies in the stepper motors. I assumed they were 12v when I took a quick glance at the page here:

    Nema 23 Stepper Motor 1.26Nm 2A 4-wires 6.35mm Shaft DIY CNC Router Mill XP9 | eBay

    But when I was about to purchase, they were 3V 3A, and I dont understand how 3V would get me 270 oz-in of torque.

    So my question is, is there something particular that low voltage stepper motors are bad at, or should i just use them. Also, since I purchased a 12v power supply, how do I get the drivers to run at 3v, is that a setting in GRBL I just change or am I missing something?

    Thanks in advance!
    If you want to build a CNC and aims at milling aluminium than you need to increase those spec considerably.

    The power supply must be above 40V, preferably unregulated analogue type (toroidal transformer, rectifier and a very large capacitor). The stepper should have VERY low inductance and at least 3A. The stepper driver is very critical for the speed performance but must match the power supply, so you can't use the crappy Toshiba chip based ones if you have a power supply which is above 36V (or maybe 24V, I don't remember any more). But not only that, milling aluminium requires a very well build, rigid machine with a lot of mass.

    https://www.youtube.com/c/AdaptingCamera/videos
    https://adapting-camera.blogspot.com


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    Default Re: Low Voltage vs High Voltage Stepper motors?

    Extremely helpful, thank you!

    I was actually able to wake up at 6am and win the auction you posted, I think I got it for a fairly good deal considering any set of just 4 of those motors without the rest is around 200, then the 2 power supplies + motor drivers + BOB, I think it was pretty good, thanks!
    Those should get me up and running for a while until I want to upgrade. I have good deals on the extrusions and rails and ballscrews, which I intend to buy. The last part I need help with is the spindle. I know I want a watercooled 1.5kw VFD spindle, but the cheapest I could find is 450CAD, which is way more than I expected, do you think I could get it for cheaper?

    Thanks again!



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    Quote Originally Posted by A_Camera View Post
    If you want to build a CNC and aims at milling aluminium than you need to increase those spec considerably.

    The power supply must be above 40V, preferably unregulated analogue type (toroidal transformer, rectifier and a very large capacitor). The stepper should have VERY low inductance and at least 3A. The stepper driver is very critical for the speed performance but must match the power supply, so you can't use the crappy Toshiba chip based ones if you have a power supply which is above 36V (or maybe 24V, I don't remember any more). But not only that, milling aluminium requires a very well build, rigid machine with a lot of mass.
    I totally disagree. There is nothing that says you have to run 40V or have a torroidal transformer or any of the other stuff mentioned. Here is my latest machine which breaks all of those rules and yet still works somehow. The machine has dovetail slides for more friction, acme screws with finer pitch than a ballscrew to make things worse, 425 oz-in 6.8mH motors, cheap $8 TB6600 drives and in this video is running from a 24V switching power supply. It milled just fine and was capable in this video of about 25 IPM rapids. It all depends on the performance you want.



    My first machine is in the second video and it had TB6560 drives at 24V, underdriving some 570 oz-in 2.2mH motors. These were 5A motors being driven at 3.5A, so were immediately at 70% power just due to the low amperage, and then were at lower performance due to running at about 1/2 their ideal voltage. The machine did have ballscrews, but had dovetail slides still. Even with all of the supposed no-nos on that machine, I was able to cut aluminum just fine, and actually did some steel cutting too. without problem.



    Bottom line is that what will work depends what performance you are desiring, not what others feel is absolutely necessary.



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    Thanks for this post, this is what I expected to be doing. With the electronics I got I should be just fine.



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    I am a big fan of Leadshine's DM542A; if these are truly a rebranded equivalent then you got a good deal. They're capable of up to 50V.

    You should note that this torque rating is at motor stand-still, at full step, and idle-current-reduction off. So the actual stall torque will be a little lower. As to voltages, in general the speed of the peak power output of the stepper will increase proportionately to the voltage. Mariss Freimanis' voltage formula is a good basis for max voltage, though as 109jb says, this doesn't need to be met. What happens is, the voltage "pushes" the current through the windings, then when the winding reaches the current set by the drive, the drive will cut off or "chop" the voltage, and the process restarts. As a higher voltage will allow the current to flow faster through the coil, a higher voltage will normally mean more torque available at higher speed.

    Almost no company publishes the power/speed curve of their steppers, and it would be beneficial to plot it yourself to determine what speed offers the peak power output of the stepper you chose, which would help determine the best pitch screw for your application.



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    Quote Originally Posted by Brian_M View Post
    I was actually able to wake up at 6am and win the auction you posted, I think I got it for a fairly good deal considering any set of just 4 of those motors without the rest is around 200, then the 2 power supplies + motor drivers + BOB, I think it was pretty good, thanks!
    OK, well, it sounds like you just got married to that system. I wasn't trying to get you to make an impulse buy, but, for better or for worse......

    Quote Originally Posted by Brian_M View Post
    Those should get me up and running for a while until I want to upgrade.
    Upgrade? I don't think you'll need to upgrade. You just did the upgrade from the 200 oz in you were thinking of at first. .

    So I did manage to find a graph for those motors. The graph I found is running from 48 Volts, so with the 36 Volts in that kit, you can expect the performance to be a little bit less that what is posted in the graph.

    Low Voltage vs High Voltage Stepper motors?-23hs9442-png

    I took the numbers from that graph and really quickly put them in my spreadsheet. The motor inertia was almost the same between the two motors.

    Low Voltage vs High Voltage Stepper motors?-brian_m2-jpg

    That's just my interpretation of the system. I do think that at this point your only good option is the 10mm lead ballscrews. I'm guessing 1605 and 1610 can be had for around the same price?

    The other option would have been to get some really fast Nema23 motors like A_Camera has and use the 5mm lead. But since you have purchased the motors, I think 10mm is now a no brainer.

    Quote Originally Posted by Brian_M View Post
    I know I want a watercooled 1.5kw VFD spindle, but the cheapest I could find is 450CAD, which is way more than I expected, do you think I could get it for cheaper?
    I have no idea where you should buy your spindle, but I think some other members of the forum can help you in that department.

    Quote Originally Posted by Brian_M View Post
    Thanks again!
    You're very welcome! I do hope it works out for you.



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    And this is where I found that graph in case anyone was wondering:

    EU ship 4axis Nema23 stepper motor 2.8Nm 23HS9442 &amp;Driver DM542A 2PCS POWER



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    Quote Originally Posted by NIC 77 View Post
    That's just my interpretation of the system. I do think that at this point your only good option is the 10mm lead ballscrews. I'm guessing 1605 and 1610 can be had for around the same price?
    Well I was searching it its actually much more expensive since its way less common, it would be nearly 1.5x to 2x the price, which I really cant do. I can deal with the slower speeds.

    Ill see if I can find a good thread on spindles, this thread has really helped me, thanks to everyone who replied !



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    Default Re: Low Voltage vs High Voltage Stepper motors?

    Quote Originally Posted by Brian_M View Post
    Well I was searching it its actually much more expensive since its way less common, it would be nearly 1.5x to 2x the price, which I really cant do. I can deal with the slower speeds.
    Where are you searching? EBay? Have you tried Aliexpress? I looked at your spreadsheet:

    https://docs.google.com/spreadsheets...BqE/edit#gid=0

    You have 166+74+54 budgeted. That's 294. Is that USD? Does that include couplers and ball screw nut housings? I don't know, I just did a very quick search on aliexpress for "1610 ball screw" and "1610 ball screw with end supports" and there are several results.

    I bet if you asked for a few quotes with your specific lengths and end machining you could easily get the 1610 including shipping for 300 - 350 USD including end supports.

    Perhaps ask this guy what he can do for you. At the very least, I'd say look around a bit more and make some inquiries.

    2 Lead screw ball screws Anti bachlash ballscrew 1610-1250mm with balnuts-C7 | eBay

    That's all the advice I have good luck to you!



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Low Voltage vs High Voltage Stepper motors?

Low Voltage vs High Voltage Stepper motors?