Magnetics, Inc. don't know how to calculate wire sizes

[Chris Carlen]

Hi:

Look at page 40 in this document on their powder cores:

http://www.mag-inc.com/pdf/2004_Magnetics_Powder_Core_Catalog.zip

The wire diameters and areas are way off from what you'd calculate using
the AWG formula:

d = 0.005*92^((36-AWG)/39) [in]

I thought maybe they were insulated diameters, from their use of the
term "heavy build".

But if that was the case, then the areas would still be right according
to the AWG formula. But they are too large as well.

For instance 22ga wire should be:

d = 0.02535 in = 0.6438 mm
A = 642.4 circ mils = 0.3255 mm^2

But Magnetics lists:

d = 0.701 mm
A = 810 circ mils = 0.411 mm^2


Notice, their area doesn't match the diameter, which would lead to 0.386
mm^2.

What are they doing?

Interestingly, their current capacities are close to, but still a bit in
error from the values one would calculate based on the correct areas
(the copper, not the insulated wire).


Good day!


--
_______________________________________________________________________
Christopher R. Carlen
Principal Laser/Optical Technologist
Sandia National Laboratories CA USA
crcarle@sandia.gov -- NOTE: Remove "BOGUS" from email address to reply.

 

[John Fields]

On Fri, 14 Jan 2005 09:50:36 -0800, Chris Carlen
<crcarle@BOGUS.sandia.gov> wrote:

Hi:

Look at page 40 in this document on their powder cores:

http://www.mag-inc.com/pdf/2004_Magnetics_Powder_Core_Catalog.zip

The wire diameters and areas are way off from what you'd calculate using
the AWG formula:

d = 0.005*92^((36-AWG)/39) [in]

I thought maybe they were insulated diameters, from their use of the
term "heavy build".

But if that was the case, then the areas would still be right according
to the AWG formula. But they are too large as well.

For instance 22ga wire should be:

d = 0.02535 in = 0.6438 mm
A = 642.4 circ mils = 0.3255 mm^2

But Magnetics lists:

d = 0.701 mm
A = 810 circ mils = 0.411 mm^2


Notice, their area doesn't match the diameter, which would lead to 0.386
mm^2.

What are they doing?

---
Dunno, but an inquiry to:

http://www.mag-inc.com/contacts/contact_form.asp

should get you an answer.


--
John Fields

 

[Ken Smith]

In article <cs90pc01q9a@news3.newsguy.com>,
Chris Carlen <crcarle@BOGUS.sandia.gov> wrote:

Hi:

Look at page 40 in this document on their powder cores:

http://www.mag-inc.com/pdf/2004_Magnetics_Powder_Core_Catalog.zip

The wire diameters and areas are way off from what you'd calculate using
the AWG formula:

d = 0.005*92^((36-AWG)/39) [in]

I thought maybe they were insulated diameters, from their use of the
term "heavy build".

But if that was the case, then the areas would still be right according
to the AWG formula. But they are too large as well.

For instance 22ga wire should be:

d = 0.02535 in = 0.6438 mm
A = 642.4 circ mils = 0.3255 mm^2

But Magnetics lists:

d = 0.701 mm
A = 810 circ mils = 0.411 mm^2


Notice, their area doesn't match the diameter, which would lead to 0.386
mm^2.

What are they doing?

This is just a guess but I think they are including a packing factor in
the cross sectional area. The windings can never use up 100% of the
space.

--
--
kensmith@rahul.net forging knowledge

 

[Rich Grise]

On Fri, 14 Jan 2005 09:50:36 -0800, Chris Carlen wrote:

For instance 22ga wire should be:

d = 0.02535 in = 0.6438 mm
A = 642.4 circ mils = 0.3255 mm^2

But Magnetics lists:

d = 0.701 mm
A = 810 circ mils = 0.411 mm^2


Notice, their area doesn't match the diameter, which would lead to 0.386
mm^2.

But, interestingly, 0.6438 ^2 = 0.41447844, which is pretty close. They're
just calculating to a square window.

Cheers!
Rich

 

[Ken Smith]

In article <pan.2005.01.14.22.32.43.689419@example.net>,
Rich Grise <richgrise@example.net> wrote:

d = 0.701 mm
A = 810 circ mils = 0.411 mm^2


Notice, their area doesn't match the diameter, which would lead to 0.386
mm^2.

But, interestingly, 0.6438 ^2 = 0.41447844, which is pretty close. They're
just calculating to a square window.

ASCII Art Cross section:


!OOOOOOOOOO!
!OOOOOOOOOO!
!OOOOOOOOOO!
!OOOOOOOOOO!
----------

Notice how they stack diameter to diameter. This makes them effectively
square.


--
--
kensmith@rahul.net forging knowledge