I agree with Frank as far as this thread being helpful to me, but I would like to add another source for more information and where to get stepper motors:
motioncontrolguide.com
-OR-
more specifically:
motioncontrolguide.com/learn … tor-guide/
Can we use DRV8825 for driving Nema 17 stepper motor ?
Hello.
The DRV8825 carrier can handle 1.5A per phase without additional cooling. If your NEMA 17 stepper motor has a current per phase rating equal to or less than 1.5A, it should work with the DRV8825.
-Derrill
Hello,
i have a Fujikoki unipolar Stepper Motor with 5 leads and connected it to the drv8825. It works perfectly. I just reduced the phase current by a factor of 1/sqrt(2) and it works.
But why cannot be the DRV882 used for 5-leads-unipolar Stepper Motors? The “com”-Leads are internal connected together an thats why only 5 leads are comming out. So why can it not be used as an 6-leads-motor with bridged com-leads (Intern)?
In full step mode, without current limiting and no load, a five lead motor should work perfectly with a two phase driver. The two center taps are always at about the same potential so no current should flow.
However, if current limiting is employed and a load is in place, then there is a possibility of current flow between windings. How that will affect operation is difficult or impossible to predict, but it is hard to imagine how this could lead to better performance.
Try it and let us know how it works.
Why is it that important that it runs only in full step mode?
Today i tried to run the stepper motor with load. The stepper motor controls an expansion valve. So i took pressure on the valve with 5bar, 10bar and 15 bar. It worked without any problems by driving it.
Now i want to know if i can set other step modes. Is it a big risk?
The timing and voltage levels between the phases is very different in microstep than full step mode, but you can certainly try it and see.
Hello all,
I am new to this forum, but I want to show that a 5 wire stepper can be driven by a bipolar motor driver. You will need to connect the fifth wire to + ve terminal of the power supply and set the motor current to it’s rated current.In this configuration the N channel Transistors/ Mosfets are inactive because they are shorted fifth wire going to + ve terminal.This is not harmful to circuit.Only four P channel Transistors/ Mosfets are active and act as a uni-polar driver. Current chopper circuit is also active. Less heat is generated and motor works fine.
Regards
Shantaram.
[quote]You will need to connect the fifth wire to + ve terminal of the power supply and set the motor current to it’s rated current.[/quote]This is undoubtedly a bad idea and not to be recommended. The MOSFETs are not shorted to the + terminal, because there are inductors in the motor circuit.
I do not believe that Shantaram knows the internal circuitry of the driver chip and is in a position to make an informed recommendation.
Hello ,Jim
Actually N Mosfets are bypassed by connecting the fifth wire to +ve Terminal.This is practical experience. This works fine.
Imagine that there are no N channel Mosfets in the circuit.
Regards
Shantaram
[quote]Actually N Mosfets are bypassed by connecting the fifth wire to +ve Terminal.[/quote]No, they are not. There is a motor winding in between, in which large voltages can be induced. Are you confused about N versus P MOSFETs?
If you want to use a five wire unipolar stepping motor, the safest and best approach is to use a unipolar motor driver. “It worked for me” is not a good reason to recommend a dubious practice to others.
Hi all,
Please see the attached schematic on hoe to connect 5 or 6 wire motor to bipolar motor driver.I am using this technique since only L298 was available as bipolar stepper motor driver.
Looks complicated! This is what I’ve been using for unipolar stepping motors, and it works very well. Replace the NPNs with logic level N-MOSFETs for truly superb performance.
hello
can we use nema 17 2.8v stepper motor driving by a4988 ?
motor voltage 2.8 and we use wihch voltage ?
Hello,
I see you have posted a similar question elsewhere on our forum. We have answered your question in that other thread.
-Derrill
hello
So I have to adjust voltage to give me 1.5A per phase.
Hello.
The VREF voltage on the DRV8825 driver determines the current limit for the driver and the proper current limit will depend on the stepper motor you are using with the driver. So, if 1.5A is the rated current per phase of your stepper motor, then you should adjust VREF so that 1.5A is the current limit on the driver. You can find instructions for setting the current limit in our Setting the Current Limit on Pololu Stepper Motor Driver Carriers video.
-Nathan
hello, i have a similiar question, it might be obivous but i’m a bit skeptical.
i’m planning to buy this stepper motor of yours as an upgrade, to be driven by the DRV8825 stepper drivers of yours currently installed on my system.
I can understand that the torque is on the par with other similiarly sized more common nema 23 stepper motors even though it’s per coil current is 1A, because it’s rated at 8.6 Volts.
My questions are,
-Can i completely painlessly drive this stepper with DRV8825, just because that driver is rated around 2A(considering i have a motor power supply of 12 volts and more than enough amperes)?
-Is the only parameter that affects the heating of the DRV8825 carrier the driving current? I mean would driving a much lower torque nema 17 stepper with 1A per coil and 2.2V rating cause the same amount of heat to be generated on the chip, just because their amperage is the same?
I’ve been very late on a project and now i have to change the motors due to an unexpectedly high mass, any fast help is greatly appreciated!
thanks
Hello, gezzer.
We expect that #1477 stepper motor to work well with our DRV8825 carrier. There will be some differences in heat generation based on your motor and power supply, but the primary influence to how much the driver heats up is the current limit setting (and corresponding current draw).
-Derrill
When you use the bipolar driver to drive the unipolar stepper, can you use the fast decay or slow decay mode? I’m trying to test this architecture. Are there any other precautions?