Date: Thu Aug 9 14:25:56 2007

Author: A Gavrin

Subject: Re: Best type of iron for a solenoid

Post:

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All -

Note that there are two "categories" of solution running around in
our discussion. Solid bar (As Dick Berg and I have mentioned) and
welding rod are good choices for DC or slowly varying magnetizations.
The "insulated wire" methods (such as Doug mentions below) are
preferred for the Jumping Ring or other applications with rapidly
varying fields, because the insulation between the rods suppresses
Eddy currents.

- Andy


On Aug 9, 2007, at 11:22 AM, Douglas Johnson wrote:

>
> Steve,
> In building the Jumping Ring or Ring Toss demo, we have found
> that gas type welding rods works great, but if you can get enough
> metal coat hangers that have a painted surface, I have heard that
> these(being insulated) work a lot better for a core. I suppose one
> could spray some lacquer on the smaller gauge welding rods and do
> the same thing. I don't know about making a solid core for your
> solenoid. Every solid core I have ever used has been very
> disappointing.
>
> My two cents worth. ...Doug J.
>
> PS.. Are you using AC or DC at 30 amps? I am assuming AC.
>
>> Hi all,
>>
>> What's the best type of iron to use in a solenoid? I know mu metal
>> (or superpermalloy) is better, but I'd like to keep the cost down
>> (looking to have 4" bore). MMC has cast gray iron (ASTM A48) and
>> ductile iron (ASTM A46) in this size. If it matters to you I want
>> to generate a field of at least 1000 G with using about 30 amps
>> and a reasonable number of turns/inch.
>>
>> Other suggestions?
>>
>> Thanks!
>> **********************************
>> Stephen
>> Irons Yale
>> University
>> Director, Instructional Laboratories Department
>> of Physics
>> tel: 203-432-3664
>> P.O. Box 208120
>> fax: 203-432-6175
>> New Haven, CT 06520-8120
>>
>> COURIER DELIVERIES PLEASE USE
>> Yale University
>> Department of Physics
>> 217 Prospect Street
>> New Haven, CT 06520
>



________________________________
Andrew D. Gavrin
Associate Professor of Physics
Associate Dean, IUPUI School of Science
LD 222, 402 N. Blackford St.
Indianapolis, IN 46202-3273

317-274-6909 (Phys)
317-274-0636 (Sci)
agavrin@iupui.edu



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Note that there are two =
"categories" of solution running around in our discussion. Solid bar (As =
Dick Berg and I have mentioned) and welding rod are good choices for DC =
or slowly varying magnetizations. The "insulated wire" methods (such as =
Doug mentions below) are preferred for the Jumping Ring or other =
applications with rapidly varying fields, because the insulation between =
the rods suppresses Eddy currents.- AndyOn Aug 9, =
2007, at 11:22 AM, Douglas Johnson wrote:=A0=A0 In building the Jumping =
Ring or Ring Toss demo, we have found that gas type welding rods works =
great, but if you can get enough metal coat hangers that have a painted =
surface, I have heard that these(being insulated) work a lot better for =
a core.=A0 I suppose one =
could spray some lacquer on the smaller gauge welding rods and do the =
same thing. =A0 I don't =
know about making a solid core for your solenoid.=A0 Every solid core I have ever =
used has been very disappointing.=A0 ...Doug J.=A0 Are you using AC =
or DC at 30 amps?=A0 I am =
assuming AC.=A0 is =
better, but I'd like to keep the cost down (looking to have 4" bore). =
MMC has cast gray iron (ASTM A48) and ductile iron (ASTM A46) in this =
size. If it matters to you I want to generate a field of at least 1000 G =
with using about 30 amps and a reasonable number of =
turns/inch.=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 Yale University=A0 =A0 =
=A0 =A0 =A0 =A0 =A0 =A0 =A0 Department of Physics=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 P.O. Box =
208120=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 New =
Haven, CT 06520-8120=A0 06520 agavrin@iupui.edu =
=

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