Aluminum Wires vs. Copper Wires

http://www.houwire.com/products/technical/article310_16.html

Karmalamiri,

To get equal resistance, your aluminum wire must have 64% greater cross-section than the copper wire. This is the ratio of their resistances at 20°C. The table previously given was the USA's code table for building wiring, not insulated motor winding wires. As wire sizes get larger, the "skin effect" starts to become quite important in determining current flow and current-carrying capacity. However, in the sizes typical in most motors (but not always in form-wound large machines), the ratio of cross-sectional area is a good approach. You can see that aluminum conductors need more area in the slots of a motor than copper conductors. For that reason, a rewind of a stator using copper (when the old was aluminum) can be engineered to increase the motor's power output.

--JMM

Your electrical code will have the sizing in it (US and Canada atl east).

Hello karimalamiri:

And welcome as this seems to be your first thread?

I have to ask............why aluminium wires? If you are winding a motor everything is very much larger. Of course if you are rewinding a motor which had aluminium wires anyway, it makes sense. Just interested.

Are you in India and you wand a supplier from your local district?

I will put a couple of sites below. If you are not in India please tell me if you want these sites or do you have the things you need like wire, terminals etc ok?

123India.com Electrical : Companies : Business and Economy

Alcon Engineering Industries - copper and aluminium cable terminals .... Hi-Tech Resistors Pvt. Ltd. - manufacturer of wire wound, fusible & low ohm metal ...
dir.123india.com/business_and_economy/companies/electrical/ - 75k - Cached - Similar pages

High winding density micro coils for magnetic actuators 25 micron aluminum bonded wires complete the winding. on top. Figure 3 shows an externally wound micro coil with 400. turns of insulated copper wire ...
www.springerlink.com/index/A7Q9GVYUP74Y86XM.pdf - Similar pages
by J Klein - 1998 - Cited by 4 - Related articles

Take care and good luck...............

Sir:

Based on personal experience...I never use aluminum wires any more.

As a developer/contractor with several buildings of my own for 20 plus years.......aluminum wire has one very adverse problem.

Because of the co efficient of expansion......and aluminum's greater expansion by heat...if any where near utilized at greater than 70% of design load..the heat generated in the wire by supplying the load will cause a greater physical expansion of the wire...this compresses/deforms the wire, where ever held mechanically, by a set screw, kearney or terminal screw creating a situation after high load is no longer in the circuit...cooling back to ambient...leaving a less tight clamp at that connection...now possible slight arcing can occur...if so, greater additional heat is generated..arc again carbon created...offering added resistance next high loaded condition exacerbating the situation........with eventual fire or burn off wire.

In buildings I still own where aluminum wire has not been changed out........we at least annually inspect and re tighten those aluminum wire terminals.

I have just up graded/changed out to copper a building built in 1954....last one of mine left with aluminum on main service conductors.....

MR. GUY.

Old technology Aluminum wire normally to be used for transformer winding, its designed to limited of short circuit current, currently Cu is using for almost of these winding, Some of Squirrel cage rotor bars still using of Al bars. you can modified from Al to Cu or v.v, but you must concerned to their material properties.

Modified from Cu to Al need much space to accommodate these conductors

following table may help you to calculation :

Good luck

Rgds

Sis