Formula For Insulation of Sector Wires or Cables

Hello everyone;

For introducing myself, I should mention that I've been working as an Industrial Engineer in a big wire and cable manufacturing company for about 5 years till now. One of my duties is indicating the construction of different power cables and now I have a problem in my business. I need a formula for indicating insulation in sector power wires or cables.

Thanks to anybody who could help me.

Hello Wise,

I think you should talk this over with the Manager of your Product Engineering Group. You may have to use "look-up" tables.

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

Hello dear Vettecoupe;

Thanks for your reply.Unfortunately, our Manager of Product Engineering Group has recently retired,and I don't have enough access to essential information. In other hand, I've used parameters of insulation quantities which have achieved from "one meter samples" of different types of sector power cables produced in our company. Consequently, I decided to find a "Formula" for defining quantity of insulation in sector cables. Would you mind if I ask you for more help?

Regards
This email address is being protected from spambots. You need JavaScript enabled to view it.

Hello again Wise,

Unfortunately I do not have the answers you desire. In fact, I can say that I have never seen such equations. It would however be fairly straightforward to use a planimeter to determine the area of the plastic on an accurate, scaled-up, cross-section design drawing of the insulated sector. This then could easily be converted to weight per unit length using a particular length cable and the specific gravity of the plastic. The only thing that concerns me is accuracy so verification by actual measurement is definitely a must. This then would give you a table which could be used by all.

Do you use an optical comparator or shadow graph something like the Starrett VB 400 www.adwin.co.uk/latest_technology.html or the Mitutoyo optical comparator www.solomonmachinery.com/other-machines/...ticalModelPH350.html along with accurate, scaled-up, outline drawings in ink on transparent film?

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

Hi Wise,

Whilst the suggestion made by Peter are certainly useful none of these instruments provides you with the most accurate measurement since all rely on the ability of the operator to make a correct assessment.

ACM AB of Sweden manufactures a digital measuring and data aquisition system called KSM.Statisically the error with such systems is in the region of 7-10%.

More information as well as videos of operating the KSM you can find at www.acmab.com/Info/ and www.acmab.com/Info/Video.

During the Interwire 2011 in Atlanta (May 2 -5) ACM will demonstrate a KSM in operation at the Howar Equipment stand 1612.

Best Regards,

Willy Hauer

Hi Willy,

While I agree that the KSM unit will give the most accurate measurement, all Wise wants to do is develop some equations. Moreover the measurements are to be done by Wise and not the operators. The very high cost of the KSM unit is not justifiable in this case unless it instituted as a measurement tool for all extrusion at their plant. This is why I did not mention the KSM unit. Since Wise left his personal E-mail address above and since he is located on the other side of the World, I would suggest that the appropriate person at ACM AB contact Wise and see if it is indeed possible to give the Wise and his company a presentation so it can determined whether or not they have a justification for such equipment.

I certainly believe in the KSM equipment and I have personally recommended it more than once to our clients around the world. Likewise, I go a long way back with the owners of ACM AB, almost as far back as the Lars Olof Hertsius days at Mechanomatic in Stockholm.

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