Re: Aluminium Wire (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Fri, 28 Sep 2007 18:07:36 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Aluminium Wire  (fwd)

Does anyone know if the oringal poster of this thread meant aluminum for 
sec or pri? I was under the assumption that he intended on aluminum 
magnet wire which is a whole different animal then low L & low R primary 
windings.

It's not a myth, but it's understanding of "when" is it bad must be put 
into perspective.

The "resistivity" "is" the determinant and applies to AC and DC 
directly, skin effect, etc. In a secondary winding application, the 
effect would no longer be negligible as it is in a primary winding. 
Resistivity is the ability of a conductor to transmit electrical energy. 
The material and geometry of the conductor go hand in hand with this 
one. At RF, the usable geometry decreases, and if the resistivity is 
high enough, it will result in higher losses which at some point will 
become a noticeable factor.

Some might be surprised that the resistivity of tungsten at 5.6 (where 
aluminum is 2.77 and copper at 1.65) (those values are x10^-8 
ohms/meter). But as we use such a short piece of stock (geometry), it's 
no big deal in a spark gap application. You wouldn't want to wind a 
secondary out of tungsten however. BTW, Iron is at 9.71 (for some 
perspective). And why is Nichrome used for heating elements? Because it 
has a resistivity at a whopping 100 (among other mechanical properties).

For me it's no myth, just physics. But would help if we put the word 
"bad" into perspective.

Take care,
Bart


Tesla list wrote:

>---------- Forwarded message ----------
>Date: Fri, 28 Sep 2007 07:42:06 -0400
>From: "Lau, Gary" <Gary.Lau@xxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: RE: Aluminium Wire  (fwd)
>
>Yes, I believe that aluminum being "bad" for RF is just one of those
>myths that won't die.  I performed an exhaustive test of various primary
>conductor geometries, including Al vs. Cu wire.  Aside from the DC
>resistance being different, the Al primary did not exhibit any
>surprising increases in AC resistance as I swept from 40 KHz to 800 KHz.
>See http://www.laushaus.com/tesla/primary_resistance.htm
>
>Regards, Gary Lau
>MA, USA
>
>  
>
>>From: Dr.Hankenstein <Dr.Hankenstein@xxxxxxxxxxxxx>
>>To: Tesla list <tesla@xxxxxxxxxx>
>>Subject: Re: Aluminium Wire  (fwd)
>>
>>Why would aluminum be considered "bad" for RF?
>>My antennas work great...and they're made out of aluminum!
>>So does the top-load on my tesla coil...five foot cross section, 5kva
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>input, 10 foot
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>>sparks....and it's aluminum! see:
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>http://www.drspark.org/images/wwt6.jpg
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>>Perhaps working with unconventional materials and designs is what
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>coiling is all
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>>about; what do you think?.
>>
>>Woo
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>>
>>    
>>
>>>[Original Message]
>>>From: Tesla list <tesla@xxxxxxxxxx>
>>>To: <tesla@xxxxxxxxxx>
>>>Date: 9/27/2007 7:52:22 PM
>>>Subject: Re: Aluminium Wire  (fwd)
>>>
>>>
>>>---------- Forwarded message ----------
>>>Date: Thu, 27 Sep 2007 18:21:09 -0500
>>>From: resonance <resonance@xxxxxxxxxxxx>
>>>To: Tesla list <tesla@xxxxxxxxxx>
>>>Subject: Re: Aluminium Wire  (fwd)
>>>
>>>
>>>
>>>Alum will work but limits your peak primary current.  Alum is not
>>>      
>>>
>very good
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>>>at RF frequencies.  It is used for 60 Hz commercial power
>>>      
>>>
>transmission lines
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>>>but not good above a few hundred Hz.
>>>
>>>Been there, done that, and took measurements.  Alum was a loser for
>>>      
>>>
>best
>  
>
>>>coil performance.
>>>
>>>Dr. Resonance
>>>
>>>
>>>
>>>Resonance Research Corp.
>>>www.resonanceresearch.com
>>>      
>>>
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