Aluminium Cable Conductors "Work Hardening"

[netorius77]

I am currently putting together a justification to install aluminium conductor 6.6kV cables on a relatively large project we are working on. The major advantage being the significant cost savings that can be made using the aluminium conductor cables rather than copper.

A query has been raised about aluminium cables "work hardening" due to the vibration at the connection of large electric motors. This may lead to conductors becoming brittle over a period of time and ultimately "cracking".

The motors (range between ~1MW and 2.5MW) drive conveyors, so vibration should not be "abnormal". I did not consider this in my justification and wondered if anyone had any experience with this (or any other concerns) that I should consider (or maybe point me to any published literature).

Thanks

 

[netorius77]

Sorry, I should have included that I did read the following thread, but it didn't cover what I was specifically looking for.

http://www.eng-tips.com/viewthread.cfm?qid=180875&page=3

 

[netorius77]

Although I have had no response to my question, further research has led to me to continue with my recommendation to use aluminium conductors as I am unable to find any significant recorded issues against aluminium conductors.

I have had to conclude that the concerns were fueled by poor workmanship or possibly utilising an incorrect technique or non-compatible cable accessory. Further it appears that modern alloys have also enhanced the meleability and flexibility of the product.

I attach two datasheets, one indicating the different properties of the different aluminium alloys that are available and their advantages with the second a comparison of aluminium against copper that was quite useful:

http://www.daycoindustries.com/pdfs/Aluminum_Alloys_Temper_Designations.pdf

http://www.ucable.com.my/catalogue/aluminium_rod.pdf