RandyWales Posted July 4, 2012 Share Posted July 4, 2012 Hi all... Advice needed please.... Although my layout is DCC for train control, I intend to use conventional wiring for points and signals. I'd like to keep my long point-motor cable runs as neat as possible, and having tried and failed to wrap three cables together using Maplin cable wrap (it might be possible in three lifetimes ), I was wondering if this idea would work. I've stripped a CAT5 (computer network) cable, and as the image below shows, I've joined four pairs. While I would think that the individual cables are too thin to carry sufficient current, would joined pairs do the business? regards Randall Link to post Share on other sites More sharing options...
cpman46 Posted July 4, 2012 Share Posted July 4, 2012 Hi Randall Could you give me an idea of what point motors you're using and how you are driving them e.g. Peco / Seep with CDU?, Tortoise? Also the lengths (approx) of your long runs. Is the cable you're using solid core or stranded? Can advise better once I know the details but would think your pairs twisted together would be ok. Regards Mike Link to post Share on other sites More sharing options...
Kenton Posted July 4, 2012 Share Posted July 4, 2012 Why not use cable ties - they pull together wires and can even be used with self adhesive pads. There's one on the side of this point motor (and many more to be used on the layout as I wire it up) If you are using a CDU to drive solenoids I don't think that thin wire is up to the job. Link to post Share on other sites More sharing options...
RandyWales Posted July 4, 2012 Author Share Posted July 4, 2012 Could you give me an idea of what point motors you're using and how you are driving them e.g. Peco / Seep with CDU?, Tortoise? Also the lengths (approx) of your long runs. Is the cable you're using solid core or stranded? Can advise better once I know the details but would think your pairs twisted together would be ok. Hi Mike... Went off to do other things and got to thinking I should have provided details such as these The motors are Seep, with a Gaugemaster CDU, and the cables are multicore and the l-o-n-g-e-s-t run should be no more than five metres. I was wondering whether a twisted multi-strand pair would have the same characteristics as a thicker cable. It's double the number of strands, but does that count as they are insulated from each other except for the twists either end? Kenton...Thin wire for this application was my worry, and I'd looked at solid-core CAT5 before and rejected it. I agree cable ties would do the job. However, I'd rather it be as neat as possible as I've already used the single multi-strand wires in an 8-wire CAT5 run for wiring my DCC multiple-control-point 5-pin DIN sockets, and they run through plastic "G" holders which have self adhesive pads. Thanks for helping. regards Randall Link to post Share on other sites More sharing options...
cpman46 Posted July 5, 2012 Share Posted July 5, 2012 Hi Randall Thanks for the info. Twisting a pair together will effectively halve the resistance of the run. my quick calculation assuming typical CAT5 cable gives a loop resistance of approx 1.0 ohms for a 5 metre run with a pair twisted together. I have no info for SEEP motors regarding resistance but assume they will be similar to Peco at about 4.5 ohms. This means in theory losing about 20% of the energy of the pulse from the CDU in the cable. This may or may not affect the operation of the point motor over the 5 metre run. Shorter distances will lose proportionally less in the cable. I suggest you hook up your twisted pairs temporarily to see whether you get reliable performance at the longest distance. If you twist 3 wires together the loop resistance over 5 metres would be approx 0.5 ohms. As a matter of interest what are you running your CDU from 16V ac? If it doesn't quite fire the longest run you could try upping the volts to the CDU but do not exceed 24V ac. Also of general interest may be Brian Lambert's site at http://www.brian-lambert.co.uk covering all aspects of electrical details amongst other things if you are not already aware of it. Regards Mike Link to post Share on other sites More sharing options...
cpman46 Posted July 5, 2012 Share Posted July 5, 2012 Randall Calculations a bit off! loop resistance on 5 metre run should be about 0.5 ohm therefore loss is about 10%. On these figures I think your 5 metre run should present no problems but as indicated before try it and see. 3 wires twisted together would give you a loop resistance of approx 0.06 ohms, insignificant compared to the notional 4.5 ohms of the motor. Regards Mike Link to post Share on other sites More sharing options...
RandyWales Posted July 5, 2012 Author Share Posted July 5, 2012 Calculations a bit off! loop resistance on 5 metre run should be about 0.5 ohm therefore loss is about 10%. On these figures I think your 5 metre run should present no problems but as indicated before try it and see. 3 wires twisted together would give you a loop resistance of approx 0.06 ohms, insignificant compared to the notional 4.5 ohms of the motor. Thanks Mike...very grateful for all your help. I've always used either finger-power or wire-in-tube on previous (smaller) layouts. That's not feasible on my lengthy Costleigh layout (that name is becoming more and more literal as time goes on!). You've given me the confidence to go ahead and try it out. My power supply is 16vAC, but I've been meaning to replace it for some time. I'll give an account of how things get on in due course thanks again Randall. Link to post Share on other sites More sharing options...
RMweb Premium kevinlms Posted July 5, 2012 RMweb Premium Share Posted July 5, 2012 Why not use cable ties - they pull together wires and can even be used with self adhesive pads. There's one on the side of this point motor (and many more to be used on the layout as I wire it up) You can just staple the cable ties to the underside of a timber baseboard, near the loop, using a heavier duty stapler - not a paper one. Much quicker. If you need to remove them, just prise them out with sidecutters or whatever. Much easier than trying to clean the residue from self adhesive pads. Kevin Martin Link to post Share on other sites More sharing options...
Silver Sidelines Posted July 6, 2012 Share Posted July 6, 2012 For the wiring of my last two layouts I took some 30amp domestic cable. I stripped the brown and blue cores and ran these in parallel around the layout. They are fairly rigid and be held in place under the baseboard with home made wooden clamps. I use the brown cable as the common return for my point motors and I use the blue cable as the common return for my DC 'cab' control. It must be more than 40ft from one end of my layout to the other and if required it can all be controlled from one controller (Gaugemaster DS) without any discernable problems May be of interest Regards Ray Link to post Share on other sites More sharing options...
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