This is my first Arduino project and I am trying to connect, as aforementioned, six bipolar stepper motors to my Arduino Mega--but am facing issues regarding the PSU. What voltage and amperage would be necessary to power these motors?
For reference, they are NEMA 17s from Amazon. Motor runs on 1.5A per phase and 2.3 ohm resistance.
Drivers are cheap A4988s (also from Amazon), which I may upgrade to Polulu A4988s given the chance.
Beyond the PSU, I would also like to know if a simple solderless breadboard (which I doubt would work) is capable enough to power all six motors, or if something like a stripboard would do the trick.
Thanks in advance to all who reply... I know it is a relatively long inquiry.
Have you done any Arduino programming or electronic assembly before this?
Can you please tell us your electronics, programming, arduino, hardware experience?
Sorry but you have not even have the basics of Arduino programming, then I would suggest this project needs to be put aside until you learn some basics.
What is your project?
Nema 17 refers to the stepper mechanical specs, not the electrical.
Product Description
This bipolar Nema 17 stepper motor with step angle 1.8deg and size 42x42x38mm. It has 4 wires, each phase draws current 1.5A, with holding torque 42Ncm.
Electrical Specification
*Manufacturer Part Number: 17HE15-1504S
*Motor Type: Bipolar Stepper
*Step Angle: 1.8 deg
*Holding Torque: 42Ncm(59.49oz.in)
*Rated Current/phase: 1.50A
*Phase Resistance: 2.3ohms
*Inductance: 4.00mH ± 20%(1KHz)
Physical Specification
*Frame Size: 42 x 42mm
*Body Length: 38mm
*Shaft Diameter: Φ5mm
*Shaft Length: 23.5mm
*D-cut Length: 20mm
*Number of Leads: 4
*Lead Length: 1000mm
*Weight: 280g
Connection
A+: Black, A-: Blue, B+: Green, B-: Red WARNING
***On some systems, the middle 2 wires on the motor side are swapped. This is easy to fix by slightly prying back the white nubs and swapping the wires. Otherwise they work fine.
*** Make sure the motor connect to a constant current or chopper drive controller before you test motor. Connecting the motor directly to a power supply will destroy the motor.
A4988 is rated to 1A without additional cooling, better use DRV8825.
so we have 12 coils total
12 * 1.5A = 18A minimum, so you may take 24V 25A PSU to be sure
No! Calculating the neccessary PSU for current controlling stepper drivers isn't that easy! You cannot simply add the coil currents.
To calculate the PSU for this equipment you must consider the needed power. The Coil is rated at 2.3 Ohm and 1.5 A. That is about 5.2W per Coil. With 12 coils you need 62.4W.
Adding some headroom for losses and mechanical work, a PSU with at least 100W should be sufficent. E.g. 24V/5A. 24V/25A is highly oversized.
Obviously you don't know how current controlling stepper drivers work. And you don't seem to know ohm's law. The coil is rated for 1.5A and 2.3Ohm This are about 5.2W (P=I²R). More power will burn them.
I believe I can comprehend the basics of this--it is simply just a one-off project I intend to do, but I have a lot of past experience in coding and have grasped the C++ syntax quite well.
On the electrical end, I do not have much experience, besides some arbitrary glowing light circuits that I have done in the past, and in terms of hardware experience, I have spent a decent amount of time towards the replacement of my 3D printer motor driver (and other Raspberry Pi projects).
The project is a Rubik's Cube solver, connected to my computer's Python processes through library PySerial, which means that the project does not need more than two motors to move at one time (a physical impossibility)...
I apologize if I do not give enough details, I acknowledge that my rudimentary understanding of this fails in some aspects. I am just wondering what parts would be able to maintain such a relatively heavy load of six stepper motors, as my current build has a "falloff" after the attachment of two motors.
What I mean by this, is that when I attach the first motor with appropriate connections, it spins perfectly fine. With two, both motors become slower, and with three, they vibrate and barely function.
This is why I am wondering if I need a PSU with a higher amperage, and wondering what parts to upgrade to fit this bulky task.
For reference, my current PSU is a 12V 1A cord (which is almost most definitely the issue at hand).
I intended to set the reference voltage to ~0.6, where it still functions, but will not overheat and result in more issues for me. I calculated the max Vref to 1.2A, so I am staying a comfortable amount below that.
Thank you for the reply. I have heard somewhere that the green and black 5.5x2.1mm adapter that will connect my 24V 5A wall plug PSU have 28AWG wires inside, which is not bulky enough for my purposes. What, then would you recommend for a PSU that can power all six motors—I understand the power necessary, but I am wondering what exact PSU build to use and what adapter can be used to connect that power to my stripboard.
