Re: [TCML] Source for 1H air-core inductors

[nancylavoie@xxxxxxxxxxx]

All of this is nothing but speculation without any real dimensions. Its obvious there's inumerable ways to achieve the inductance. However current handling and in the end size are going to be what makes or breaks the whole deal. Perhaps this is getting a little drawn out ?¿. Wyatt
Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: "Lau, Gary" <Gary.Lau@xxxxxx>

Date: Fri, 19 Jun 2009 16:54:26 
To: Tesla Coil Mailing List<tesla@xxxxxxxxxx>
Subject: RE: [TCML] Source for 1H air-core inductors


Yeah, but if such an inductor is used between stages of a Marx generator, you either want a single layer, or some very non-trivial insulation between orderly layers, to stand off the voltage spikes.  Current is probably not too high.

Per WinTesla, a 1-layer 3" fist-diameter coil of 40AWG would need to be 53" long to achieve 1H.

Regards, Gary Lau

> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of jimlux
> Sent: Friday, June 19, 2009 11:58 AM
> To: Tesla Coil Mailing List
> Subject: Re: [TCML] Source for 1H air-core inductors
> 
> Ed Phillips wrote:
> > Resistance?
> >
> > Current handling capability?
> >
> > Ed
> 
> Ballparking here using Wheeler's equation
> 6" diameter, 6" long, 3000 turns is just under 1 H..
> 
> 3000 turns * 18" average turn length = 4500 feet
> 40 ga is 1000 ohms/1000ft  (roughly.. 10ga is 1 ohm/1000ft, 40ga is
> 1/1000 the area)
> 
> So 4500 ohms DC resistance, or something around there.
> 
> 40 AWG is about 30kft/lb, so we're looking at less than 1/4lb of wire.
> 
> What about if you just buy a 1/4 lb spool of 40AWG wire.
> 
> 
> Sticking with the idea of 3000 turns in the size of a standard wire
> spool... one might look at a pound of AWG 30.  Resistance would be about
> 450 ohms.
> 
> Half pound spools, 1600ft of AWG30 Beld-Sol are $45 from Mouser.
> 
> ACtually, though the spools might be too small, which reduces the
> inductance.
> 
> A one pound spool of PolyThermaleze might be closer to what you want.
> 
> 
> Didn't someone measure the inductance of a standard 500ft spool of AWG12
> THHN?  500 ft/1 ft turn (average) = 500 turns works out to about 26 mH..
> 
> 
> Current handling is going to be determined by allowable temperature rise..
> we can sort of estimate here, too..
> Let's say we can tolerate a 100C rise.  We're looking at basically a
> solid lump of copper with some plastic, so let's call it 250 grams of
> copper, which has a specific heat of .38 J/(K*g), or, inverting, 2.5
> degree grams/Joule.  250 grams, so overall rise in our spool will be
> 2.5/250 = 0.01 degree/Joule
> 
> Say we push an amp through this beast.  That's a dissipation of
> (assuming my AWG30 case) 500W, so in a second, we get a 5 degree
> temperature rise.  In 20sec, we've got our 100 degree limit.
> 
> 
> 
> 
> >
> > "That's huge indeed.
> >
> > Mine are just a little larger than two human fists held together.
> >
> > Wound with #40 AWG wire.
> >
> > D.C. Cox"
> >
> >
> >
> >_______________________________________________
> > Tesla mailing list
> > Tesla@xxxxxxxxxxxxxx
> > http://www.pupman.com/mailman/listinfo/tesla
> >
> 
>_______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla

_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla