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[on:]

hi, yesterday a fiend just give 6 stepper he had on a box, but i have no idea the power or any other data than, voltage and amp...

some are 2.8v and 2A, and others are 3v and 1.4A.... some are 6 cables, some 4 cables, and others 8 cables....




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for now i just want to connect them to my arduino uno and move them, after that. maybe i can try many other things with them..

thanks

[Reply #1 on:]

Start off by reading this:-
http://en.wikipedia.org/wiki/Stepper_motor
or
http://www.thebox.myzen.co.uk/Workshop/Motors_3.html
and
http://www.thebox.myzen.co.uk/Workshop/Motors_4.html
For the two different types of stepping motor.

Then I would recommend a regulating stepping motor driver like the one I used in this project:-
http://www.thebox.myzen.co.uk/Hardware/CNC_Conversion.html

As that regulates the current so you don't have to worry about what voltage you feed it.

[Reply #2 on:]

hi tanks for the info.

but i still have a couple of questions, first... all my steppers are low voltage 2.8 and 3.1v.... this is the real voltage??? because it makes me think this motors are very weak, but the look big enough to move a CNC homemaded.... but also 2A are high current motors no???, so im not so sure, also, i am planing to use a pc power supply to power the motors, so i have 12v lines, can i use a transitored driver?? maybe some 2n2222???....

maybe this can be stupid question, but with my tester, how do i know which it the power, and whichs are the coils???.... 

[Reply #3 on:]

Those are real motors and will do a good deal of work with a proper driver. One way of controlling them is with a commercial driver - A common one is made by Gecko - Step & Direction inputs. Feed the controller a voltage and the step and direction signals and the motor runs. Those motors can run a small mill or lathe with a 2:1 to 5:1 reduction.

Here's an idea I was working on - maybe I'll finish it up this winter - http://arduino.cc/forum/index.php/topic,84809.0.html - it uses an ATtiny2313 - takes a step and direction input and sequences the outputs to drive transistors or Mosfets to control the motor. Parts for the whole thing would be about $25 US

[Reply #4 on:]

why a reduction gear??? i was going to use them in a small cnc mill..... but i need to make them work first....

they are 2 amp, i guess are two amp per phase right???....
you said are real motors, i guess you mean they are powerful enough......

i was thinking in buy a polulu driver but, i cant get them for 2 amps per phase

[Reply #5 on:]

hi tanks for the info.

but i still have a couple of questions, first... all my steppers are low voltage 2.8 and 3.1v.... this is the real voltage??? because it makes me think this motors are very weak, but the look big enough to move a CNC homemaded.... but also 2A are high current motors no???

If you supply the motor with (using the round stepper as an example) 2.8V it will consume its peak of 2A. If you use a higher voltage you must find a way to limit the current. That would imply high wattage resistors, or, more commonly, chopping the current. In practical usage the motors will never be run at their rated voltage but rather ~12V to ~40V is common; using a higher voltage results in a higher speed.

maybe this can be stupid question, but with my tester, how do i know which it the power, and whichs are the coils???.... 

Do more reading on unipolar and bipolar motors and how the coils are laid out. When you understand those differences then you'll realize you can set your meter to measure resistance and then test the resistance between the various wires to figure out the layout.

FYI, a motor with 5, 6, or 8 wires can be used in a unipolar mode. A motor with 4, 6, or 8 wires can be used in a bipolar mode. If you're planning on building your own driver with discrete components you will find it simpler to build a unipolar driver.

One last comment: in your posts you seem to be burning through periods and question marks at a very high rate. Take more care so that you don't exceed your quota.

[Reply #6 on:]

i was thinking in buy a polulu driver but, i cant get them for 2 amps per phase

There is no need to get a driver that will supply 2A. You can adjust the drive current to what ever level you want. Running at under the rated value is fine, it is just that it will not go as fast.

[Reply #7 on:]

[/quote]

Do more reading on unipolar and bipolar motors and how the coils are laid out. When you understand those differences then you'll realize you can set your meter to measure resistance and then test the resistance between the various wires to figure out the layout.

FYI, a motor with 5, 6, or 8 wires can be used in a unipolar mode. A motor with 4, 6, or 8 wires can be used in a bipolar mode. If you're planning on building your own driver with discrete components you will find it simpler to build a unipolar driver.

One last comment: in your posts you seem to be burning through periods and question marks at a very high rate. Take more care so that you don't exceed your quota.
[/quote]

resistance its the problem in the coils, they seem tobe two coils, (unipolar as i read) every coils its about 12,5ohms in the extremes and 5.6 in the middle.... for example, 6 wires stepper has 3 wires with continuity and other 3 the same, but they dont have any conexion in the middle....

im so new in steppers, so if i use a high voltage supply, example 24v or 40v its possible to burn the coils like normal DC motors???, where i live this motors are very hard to find, so i dont want to burn them..... 

about current, maybe i dont care about speed, but i there is lower current input, the torque its lower too????