About Stepper Motors

Thread Starter

q12x

Joined Sep 25, 2015
1,771
I bought recently a couple categories of stepper motors. But they all are still on their way. They did not arrived yet.
I will need you assistance and help for their power supply and electronic driver.
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Datasheet for each of them:
1- 28BYJ-48-5V 5wires 4phase4coils
2- NEMA17 17HS4401 4wires 2phase2coils
3- NEMA 8 20BYGH34 (I cant find its specific datasheet, and this was close enough) 4wires 2phase2coils

1- The 28BYJ-48-5V is already coming with its own motor driver board. I choosed the blue one with the SMD ULN2003 on it. So this is out of the problem.
2 - 17HS4401 and 20BYGH34 are different horses. I know they are 2A for each category (or maybe more).
17HS4401 is 1.7 Amps. But the datasheet does not mention the voltage. Great. I guess....5V.
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In my mind, both their drivers must be some power transistors. I have a couple of good power transistors actually. But not as diverse as I wanted.
BD139 BJT-NPN and IRFZ44N N-type MOSFET. At 100pcs each, we can use a couple in parallel for dealing with greater power if needed.
Until they arrive, I want to make my homework with finding a proper power supply and also to prepare at least a good circuit to be built for their driver.
That's the goal so far.
I am appealing to you, if you happen to work with such motors in your past, I definetly have to hear your experience and the proper driver cct.
Thank you.
 
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MaxHeadRoom

Joined Jul 18, 2013
28,820
Stepper motors require a drive and power supply that will guarantee the plate rated current throughout the rpm range.
As the rpm increases, so does the inductive reactance of the motor, so it requires an 'intelligent' drive of some kind that keeps the current constant.
 

Thread Starter

q12x

Joined Sep 25, 2015
1,771
Thank you @ericgibbs , very good movie tutorial !!! I start to get it.
to @MaxHeadRoom - excelent explanation, thank you. I am completly naked here with these motors (from a knowledge point of view) meaning that I really didnt keep at all, my eyes on the progress it has made over the years for their driving and powering. This is all very new to me !
So I have to buy also these 'inteligent' drives as well, right? For each motor 1 drive box like that? I expect 3 motors to arrive. So 3 drives? Aiaiaiai.... ok then.
 

Thread Starter

q12x

Joined Sep 25, 2015
1,771
My friend @MaxHeadRoom, can you look specifically on aliexpress and choose 1one that you think is best? Not other websites but aliexpress. Because I am after something that is cheap enough (I have 3 to take) and general use enough. Just pick one that your expertise dictates and for me will be more than good enough to guide myself after that. As a point of comparation.
Actually I find the driver presented in the youtube movie : TB6600 stepper motor driver
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MaxHeadRoom

Joined Jul 18, 2013
28,820
I have never used any of the Chinese manuf. drives, but the ones that Eric shows in #2 seem popular. I would select the same/similar model for your size of motors.
Also check the feedback rating.
 

Thread Starter

q12x

Joined Sep 25, 2015
1,771
I just find this guy and I believe him.
I start to question my original finding for TB6600 and I give it another search for DM542 which indeed is a bit more expensive.
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Probably that TB6600 is designed for less power than it is saying it is. Or just not so quality ICs inside. I really dont know what to think at this point. I believe I will take only 1one DM542 (because it is as expensive as 1 motor alone), for the moment and I believe I can make a switch driver using only this 1 device but using 3 motors. Of course, they will run one after another and not in the same time, but that is an acceptable bargain for the moment.
- What do you think?
- How expensive is the cheapest american brand that you recommend?
 

Jerry-Hat-Trick

Joined Aug 31, 2022
588
https://www.arduino.cc/en/Tutorial/LibraryExamples/StepperSpeedControl is a good place to start in my view. I've used the SN754410 H-bridge driver several times (in place of the ULN2000 series ICs - it's limited to 1A but if your application doesn't require too much torque then resistors in series with the coils to limit current. The fact that the arduino can control the SN754410 with 5V (Vcc1) but can drive the motors up to 36V (Vcc2) really gives you a fair amount of power if you select a lower current, higher voltage motor. The arduino has a stepper library, but I prefer to write my own - easy when you undertand how steppers work
 

Thread Starter

q12x

Joined Sep 25, 2015
1,771
I have some problems with these:
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Exactly like you I really thought they are BIG motors.
I am not accustom with this 'NEMA' brand or any other motor brand. So I had to 'learn' the hard way it's size system.
That NEMA8 means 8mm and not cm as I imagined !!! and 20,34,40,50 are mm and NOT cm !
What a disaster. I really got confused when looking on a couple of tens of results and then I choose these based on the 'lower' price, I overlook completely its real size. Also they strategically omit the mm part as well. I had to dig into its datasheet provided on their purchase page - very fortunate; to realize its in mm and not cm, and that was a bit hard to find as well. Not at all direct or clear. Remember I could not find this name datasheet at all on google.
It is a financial disaster for me right now, and I really hope I can recuperate my money. I spoke with the sender already and he shipped the package and no refund (he said) is possible. I already embraced the idea I am screwed and I move on, but still, great grief on my soul right now. What a stupid mistake. They count on stupid mistakes, thats their hole web bizniss orbiting around.
But I will receive the other steppers that are fine (theoretically).
 
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MaxHeadRoom

Joined Jul 18, 2013
28,820
The resistor method relied on using a high voltage to drive the motor, the resistor based on the stationary resistance of the winding to produce the stated current, as the inductive reactance went up with rpm, the volt drop across the resistor was less, resulting in a fairly constant current.
Crude, but fairly effective.
 

Thread Starter

q12x

Joined Sep 25, 2015
1,771
To be completly sincere, I have no idea of the "old" resistor trick to drive the coils of a motor !!!
- I can imagine what it could be though...
if 2 resistors are put on each end of the 2 coils of the stepper motor, that will indeed lower the current, but I guess... some power resistor like 1W at least probably, will be needed not the usual 1/8W smd or 1/4W. Depends on the motor coils and size maybe. This is a field I didnt play much, only a little, I know -some- basics but not too much in depth.
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- You are right mister @MaxHeadRoom, using a PWM to control the current is more efficient because you can command it and vary it electronically from arduino IO or a simple 555 cct. Compared to the resistor method mentioned and that I dont think I ever try it, this way is a fixed way. You place the resistors and thats it. It will run at a certain level, no more, no less. I think it can be made variable but from a Voltage source and thats another complicated circuit in itself....(if we talk about 100W or more powerful - I never built anything at this scale) But if is low power like 1W or less ... probably with a voltage regulator? Hmmm Very interesting !
 
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That NEMA8 means 8mm and not cm as I imagined !!! and 20,34,40,50 are mm and NOT cm !
What a disaster.
Sorry about that. I have a box full of bits where I got it wrong. You are only one order of magnitude out....

I wonder if you'd like to share with us what you are trying to do? Stepper motors are great for simple position control because they are relatively easy to drive without the need for sensing angles and more complex feedback control. But, they can easily slip if you try to turn them too quickly or too near their torque rating. For slow speed and high angular resolution geared motors are great - your 28BYJ-48 – 5V Stepper Motor has a gearbox which I think has a 64 to 1 ratio and each step angle of 5.625 degrees so 64 steps per revolution - so with the gearbox that's 4096 steps per revolution - great if you need accuracy, and the gearing means the output torque is high. I think most of the NEMA motors have 200 steps per revolution, without a gearbox and I think if you try to drive them much over 1 rev/s they will slip. So it's really important to specify required performance in terms of torque and speed and angular resolution.

Discrete H bridge circuits are not complex if you need high current although there are other higher current integrated devices on the market
 
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Thread Starter

q12x

Joined Sep 25, 2015
1,771
I wonder if you'd like to share with us what you are trying to do?
Nothing right now in particular, only to have them in my arsenal, something I can put my hand on and try when a project comes in mind and I want a quick experiment to make. I have some serious stuff to make, later in the future, but for the moment, I guess stacking up is the right description of what Im doing. I would also very much like to test their functionality - to see IF they are actually good and not having potatoes inside. I get used to this idea of testing immediately after purchasing, to reassure myself that is good or bad. So I will still have to make a verification and performance test when they arrive. Hopefully with your experienced help, since it will take way less time for me to do it. Hopefully, we'll see. Thank you in advance and I am glad you are thrilled as I am. Hehe.
- I REALLY wanted some BIG steppers in my arsenal as well, as much as 8pcs if possible. But.... aaah. I literally f**kitup this time. Aaah.
 

Thread Starter

q12x

Joined Sep 25, 2015
1,771
Here is the actual aliexpress _webpage_ I buy from. Scroll down to see the specifications of the motor.
Also for easy reference here is the datasheet of this particular motor 'I choosed' in my neatention.
So you can see is literally TINY.
20mm (or 2cm) wide and 50mm (or 5cm) Long.
I realized how small it was when I read that M2 screw and I couldnt believe it. M2 stands for Metric 2mm ⌀ in diameter.
And this is all there is to this datasheet. Only 1 page. Very minimalist. You see, its not obvious from the first glance what measure they use. They measure in 'MAX'. If you fast looking over it, fugitive like I did, you swallow it. I really hate this kind of misdirection and unclarity. Someone should fine them with a fat fine, and not these ones here, but all of them who practice misdirection like these pranksters. Maybe in the future, in the year 4022. We are patient.
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Thread Starter

q12x

Joined Sep 25, 2015
1,771
Small update: - These guys arrived in my country! Usually is like that. I made the purchase on 10 and now is 12 so in literally 2 days !
But it will take 1 or 2 months until FROM my country, the package will arrive in my TOWN. Great system we have here, full of old farting ladies with cigarettes in their mouth, who ask you "what do you want? get out of'ere, stay in line, outside yes, there in the cold, coz we like winter".
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To be fair, where they have specified “max” dimensions, it’s because the user needs to know if the component will fit in their available space, whilst the distance between the threaded holes is specified +/- so the designer knows the minimum hole size and position for attachment. Sorry it takes so long to reach you, fortunate that they are not needed urgently for a specific project, time to prepare drive electronics and write some code for the processor. There are lots of urgently needed semiconductors desperately needed for production which are on 12 months delivery lead time!
 
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