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pgmrdan
08-07-2005, 10:56 AM
Any suggestions on how to find the purpose of the 4 leads on a small electric motor?

It's from a 5 1/4" floppy drive. I think it controlled the movement of the read/write head so should it be a stepper motor?

I'm completely unfamiliar with stepper motors.

I've done a bunch of Google searches on the label field information with no hits.

Thanks,
Dan

Mcgyver
08-07-2005, 11:02 AM
it is a bi polar stepper motor, they are very light duty, good for experimenting but not enough to drive a machine. google stepper motor tutorial and you'll have weeks worth of reading

unless you want to make or buy contoller cards, its of little use to you - ie can't use as a dc motor. on a stepper you when you rotate it, you can feel in sort of jog between positions, ie it does not rotate smoothly like a regular motor

haha beat ya this time! - I gotta try a look smart on the easy ones http://bbs.homeshopmachinist.net//smile.gif
[This message has been edited by Mcgyver (edited 08-07-2005).]


[This message has been edited by Mcgyver (edited 08-07-2005).]

wierdscience
08-07-2005, 11:03 AM
Mcgyver just took all the fun out of it http://bbs.homeshopmachinist.net//biggrin.gif

[This message has been edited by wierdscience (edited 08-07-2005).]

pgmrdan
08-07-2005, 11:27 AM
Thanks guys! That's what I needed to know.

BillH
08-07-2005, 11:42 AM
Dan, Seams like you want to get into electronics for a hobby, perhaps you should include micro controllers as well. Infact that is what I am trying to learn right now. I have an AVR developement board comming soon. Stepper motors are a great way to learn about microcontrollers. Your Bipolar motor is harder to get to work than a unipolar motor. With a unipolar motor, theres 5 or 6 wires, theres either 1 or 2 common ground wires(depending if its 5 or 6 wires) and the remaining 4 wires are for each of the coils.
Simply attach ground to ground then you apply a pulse of power to each of the 4 wires in succession to make the stepper turn. change the order to reverse direction. You can even expiriment, pulsing two wires at a time in a certain way(thats the black magic to microstepping) and doing other things. SAve those Stepper motors! by the way, that bipolar motor can very easily be made to work, theres a bunch of IC chips out tehre for controlling them, where you just tell the chip the direction you want to go and how many steps and what stepping method. Or you can read up on it and just do it thru a micro controller.
I like the ATMEL AVR microcontrollers because there is a C compiler for them that is 100% free thanks to GCC and GNU, and they have lots of memmory and kick the pants out of pic chips.

pgmrdan
08-07-2005, 12:22 PM
BillH,

Yep, I'm going through a lot of old stuff I have laying around and I'm stripping it down, throwing away junk and keeping stuff I may be able to use.

Lately I have been re-kindling an old interest in electronics. Never did a lot of hands-on electronics (except wire antennas) but had to read a lot and I did take a couple of classes to be where I wanted to be in Amateur Radio.

I expect to merge interests in metal working, electronics, amateur radio, and perhaps woodworking. My shop is rather well equipped with smaller sized, high-to-medium quality equipment. I also have more time on my hands. I'm looking forward to seeing where my interests send me. My options are pretty wide open.

I'm hanging on to the stepper motor(s) even though I may only use them to learn about how stepper motors work and never put them to any real use.

BillH
08-07-2005, 12:26 PM
You know, I just took apart an old 5.25 floppy drive and took the stepper motor out of it as well last week. Mine was a unipolar.
I also find that HP inkjets have a couple of Unipolar steppers in them as well where as the Epsons have a regular DC motor geared down and measured with a quadrature wheel.
Im thinking about making a DUAL H bridge speed control with built in mixing for my R/C tank.
Ofcourse right now I am just at the point of learning how to make leds flash with my micro controllers.

Paul Alciatore
08-07-2005, 02:29 PM
If it is from a disk drive it is 99.44% likely to be a stepper. They use two or more coils to rotate in distince steps, each coil producing a fractional step's rotation, in turn.

You can find a good toutorial on this site:

http://www.cs.uiowa.edu/~jones/

I'm sure he explains it a lot better than I could.

Paul A.

egpace
08-07-2005, 07:36 PM
Cheap robotics...

I've never done this myself, but there's no reason why it shouldn't work. Take an old dot matrix printer, remove the steppers to drive ???? whatever. Save the boards & P/S hook the whole shebang to an old dos based computer. With ms basic programming, you should be able to drive the steppers for a robotic project.

Project cost? $0.00 if you have the lots of crap laying around. Maybe $20.00 at garage sales.

Have fun,
Ed