Sqmm to circ mils and reverse,for magnet wire 1

[Grover194]

Can I have assistance in converting square millimeters (sq mm ) to circ mils.
As used to measure cross Sectional Area in magnet winding wire.

Is there a formulae for easy conversion and also in reverse.

 

[itsmoked]

I believe they are the same... But someone will come along and confirm or correct that statement.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[edison123]

1 circular mil = area of circle whose dia is 1/1000th of an inch.

1 circ mil is app 5/10000th of a sq mm


* Basically, I would like a full-time job on part-time basis *

 

[bpelec]

Here's a nice little free software tool that I use:

http://www.pwr-tools.com/

If you click on the menu "math" and then "conversion factors" and then scroll down to "square millimter", you have the conversion you want... Means you can do lots of conversions with ease.

 

[stardelta]

Are you attempting to convert square or rectangular section wire to a circular wire with the same cross-sectional area?

 

[aolalde]

Hi Grover194

The formulae to convert:
CM = 1974.5 * MM2
MM2 = CM / 1974.5
For instance; #1 AWG wire has 83,700 CM or
MM2 = 83700/1974.5 = 42.39

 

[llangford]

Grover, I hope this helps.

One square millimeter is equal to 39.37" squared =1549.9969 sq mils
To convert sq mils to circular mils, multiply by 1.2732 which equals 1973.456 c. mils.
So 1 sq mm is equal to 1973.456 circ. mils.
1 circular mil is equal to 0.0005067 mm squared.

 

[stevenal]

The two answers above do not agree given the # of significant digits given. Plugging the edison123 definition into Mathcad, I get 1973.5252413899846 CM per mm^2. Round to whatever number of significant digits you require.

 

[llangford]

I want to add an additional note on calculating magnet wire sizes: you can't simply take the width times the thickness to determine the square mils or square millimeters of the wire. A deduction must be made for the rounded corners. A quick look at the sizes in my copper engineering data book notes reductions of 2 to 8 per cent depending on the size of the wire.

 

[waross]

Don't forget to multiply your corrected square mils by pi/4 to convert to circular mils.
respectfully

 

[Senselessticker]

http://www.allaboutcircuits.com/vol_1/chpt_12/2.html

 

[stevenal]

waross,

I think you mean to multiply by 4/pi. That's where the 1.2732 comes from in llangford's treatment above. There are (4/pi)CM per mil^2.

 

[aolalde]

Maken an strict calculation, we know that "Area" can be measured in several units:
squared inches(SQIN), squared meters(M2), squared centimeters(CM2), squared milimeters(MM2), circular mils (CM), etc, etc.

For the specific case of circular mils (CM), it is the area of a circle with .001 inches diameter.
1(CM) = PI x (0.001"/2)^2 = 0.000000785398163 (SQIN)

1(MM) = 1/25.4 (IN) lineal dimension
1(MM)^2 = (1/25.4)^2 =0.0015500031 (SQIN)

How many CM in 1 (MM2)?
0.0015500031/.000000785398163 = 1973.5252

 

[waross]

Thanks for the correction stevenal
I should have done a sample calculation. That's when I always notice that I have it backwards. I'll be more careful for the next several times.
respectfully