unipolar/bipolar vs half/full wind

[mhackney]

Hello all, I purchased these steppers http://cgi.ebay.com/ws/eBayISAPI.dll...EBWN%3AIT&rd=1

listed as unipolar but can be wired bipolar. I will be driving these with a Xylotex bipolar driver. The docs that came with the motors are ver informative but they talk about wiring half wind vs full wind. Is this the same as uni/bipolar? If not, how do I wire these as bipolar?

cheers,
Michael

resisting the temptation to spin the motors until the table is done!

[Urgundiz]

If you want to drive bipolar simply ignore the center wire of the two coils and drive only the coil endings. The center wire is the wire that shows half resistance when measuring with a multimeter.

hope it helps
/U

[mhackney]

Urgundiz, thanks. The motors came with a very nice detailed wiring diagram that shows 2 ways to wire these - half and full wind. What you described is what the diagram calls half wind. On other posts here folks descibe using a full wind with the Xylotex. I am just trying to understand what these 4 terms mean. The full/half wind make sense because the wiring diagram shows them and one is 1/2 the windings as the other! What about unipolar v bipolar and how does that relate?

cheers

[Urgundiz]

Well, I am not sure without seeing your wiring diagram, but from the distance it seems that half/full has nothing related to unipolar/bipolar.

For me and based on your explanations, half wind and full wind sounds like ways of wire your coils, but always bipolar, the only difference is that you just use all the legth of the coil or only half.

Unipolar and bipolar is related with how the current travel the coils. Is unipolar if the current always travel the same direction -from positive at the common wire to ground at the ends of the coil, in general- and is bipolar if the current full changes its polarity in the coils.

To simplify: if unipolar, your common wire is used and is connected to the supply, and you 'ground' first one of the ends of the coil and then the other. If bipolar, you switch *both* ends from + to - in a opposite way at the same time.

hope it helps
/U