Using Cat 5 cable for stepper motors?

[10bulls]

I am intending to connect my 8 wire steppers to drivers using Cat 5 networking cable (as I have a lot of it!).

My question is, what would be the best way to wire the pairs.
My thoughts were...

1. Wire each twisted pair to one stepper coil (4 twisted pairs, 4 coils)
(edit) I've gone off this idea as current would be double and take an uneccesary round trip back to the driver end where the coils would be joined

2. Series connect both adjacent coils at the stepper to make a 4 wire stepper, then connect both wires from a twisted pair to each of the ends.

3. Series connect coils as per above, but only use 1 wire per twisted pair for the motor coils, then connect the other wire from each pair together and ground them at either end to help reduce noise (at the expense of twice the current flowing through each drive wire).

Can anyone see any clear benefits in any of these methods or are there any other methods I haven't thought of?

On a similar note, I have a number of small ferrite toroids from various scavengings...Would it be a good idea to loop the cat5 cable through these a couple of times to help with noise?

Any advice on this would be most gratefully received
Also my apologies if this has been covered in another post.

[fyffe555]

What voltage and current are you intending to put through the motor wire? The more usual choice is 18gauge stranded which is twice the diameter and a quarter of the resistance. Within reason, less resistance is good for the same reasons that a stepper with low coil resistance is desirable. EDIT: for clarity - the wire resistance is really an issue only if you're going to be using Loooog wires... \Edit

Cat-5 is not generally rated for power supply. Cat-5 can be used for PoE (power over ethernet IEEE 802.3af) but the specs are confusing and depending on vendor usually state either 48v at 200ma or 12v at 1a max. Regular stranded 24 gauge wire intended for power is rated at 110vac 0.5a.

Cat-5 is usually solid strand so its not a good idea to use it where movement occurs - wires will break eventually. I used cat-5 on my home switches and they broke surprisingly quickly.

As to which option 1,2 or 3 I presume your drivers are bipolar and you want to run them in series? Option 1's coils would be connected series back at the driver? If so then option 1 or 2 would be the best. Try and keep the wire length to each coil pretty much the same avoiding different voltage drops - especially if you chose 24g.

hth

Andrew

[10bulls]

Thank you for the quick response.

I intend to pass 35V at max 3A. On 24 guage wire, this is going to be ~0.5V voltage
drop on a 3ft length. The insulation would be a big worry as I presume it's not designed to withstand much heat...it certainly melts very easy when soldering :/

Thanks for pointing out the breakability issue. I should have thought of this...I've laid enough of the stuff.

Oh well! Looks like I gotta find another use for all these small odd lengths of Cat5 I've got...it makes great wire links for breadboarding...but you can only use so much.

Thanks again for the sanity check!

[esmiller]

Since you are considering wiring the motors in Series, I might suggest what I found to be a PERFECT solution:

Trailer Wiring. It comes preformed into a single bundle, is More than suffieciently heavy to handle the voltage/current requirements, and is neat !
It is a grouping of 4 wires, and is color coded to allow you to easily verify your wiring hookups!

I found a local hardware store that sells it from a spool by the foot length, so I put 8ft on each axis, so I can move the driver board wherever I need to.

Eddie

(BTW.. I found that 1/2 winding hookup nearly doubled my speed, and since i am using 5/16-18 threaded rod, torque is still plenty sufficient even at 12V)