Hello,

I have been running into a problem with larger sizes of concentric aluminum cable where they tend to become loose and slightly undone prior to entering the extrusion head. The end product results in a not perfectly smooth insulation.

The problem is especially apparent with 61 wire construction ie., 1+6+12+18+24. However, they seem pretty tight even after cutting down from the strander.

This is what I have done:

1. Ensure that each of the layer is properly stranded with correct shaping die. Not too tight but slightly warm after die exit.

2. Ensure that lay length is not too long.

3. Ensure that each of the brakes are properly set.

What I am about to try.

1. Wrap each end of every layer with electrical tape before cutting down the stranded wires.

2. Anneal the wires as we expect that they might be too hard to conform.

Any other ideas or suggestions would be highly appreciated.

By the way, the machine is a typical rigid strander.

Thank you.

Hello again fuhrerwire,

1) - What type of rigid strander do you have? "Tangential" or "Star". See www.stewart-hay.com/plant1ie.htm

2) What is the diameter of your capstan? Is it single or dual wheel?

3) - Please confirm is that you are using normally hard drawn EC grade 1350 aluminum.

4) - Before you add any more variables like annealing, lets see if your stranding process is OK as the conductor outer layer seems loose on the reel although you may not be able to see it.

Tape off about 15 feet of conductor at each end as it comes off the strander capstan but not wound on the take-up reel.. Cut and hold without twisting or coiling. Place this piece of conductor on a straight line on the floor on paper and then let it go being careful that it cannot hit you if inbred stress makes the cable seem as if it is "alive". If it seems "alive" then you likely have processing problems at stranding.

5) - Accurately check the lay on the outer layer over say three feet of the conductor lying limp on the floor and averaging. Is this the lay you expected?.

6) - Presumably you also manufacture ACSR on this machine. Any problems with inbred stress with similar sized ACSR cable? (Likely reported by your customers.)
Lets get this information together before going any further so please advise ASAP.

Regards
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com
519 641- 3212

Hello,

1. It's a Star rigid strander.
2. It's dual wheel but I am not sure about the diameter
as I won't be back in office until tomorrow.
3. Yes, it is normally hard drawn EC grade 1350
4. I will give that a try and report back.
5. I will also check that.
6. We rarely produce ACSR of larger sizes, usually just
50SQMM. but no, I have not heard complaints.

I take it you are suggesting that I could have some
problems with inbred stress?

I will report back soon.

Thank you.

Hello again fuhrerwire,

No I am not necessarily suggesting you are having a problem with inbred stress in the conductor but this is the correct time to eliminate that possibility. I am concerned however that the bearing length in your closing die om the outer layer is too short thereby not completely locking the length of lay during closing.

Cheers,
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com
519 641- 3212