Anybody know how to determine the current carrying capacity of twin wire? I
have twin 29 awg magnet wire and I'd like to figure if I could use it for
about ~150mA in a transformer I'm winding. At 700 cir.mils per amp the wire
table in the RDH4 seems to say yes(~181mA). But this is for single 29awg not
twin wire.

Also, In the RDH4 the author shows an example for a power transformer where
in he uses twin 20 awg wire instead of 17 or 18 awg. He indicates this is to
'save winding height'. And it has fewer turns per layer in his calculations,
32 TPL vs 35 of single 20awg wire. How does one figure for this difference?

I imagine a wire table of twin wire would help but that leads to my second
question:

How do I find a wire table for twin AWG wire?
A search for 'AWG wire table' yields me a bunch of normal wire tables, but
nothing for twin wire.

Any help will be appreciated.
reply:

On Sat, 15 Jan 2005 06:25:37 GMT, "GHR" wrote:

Anybody know how to determine the current carrying capacity of twin wire? I
have twin 29 awg magnet wire and I'd like to figure if I could use it for
about ~150mA in a transformer I'm winding. At 700 cir.mils per amp the wire
table in the RDH4 seems to say yes(~181mA). But this is for single 29awg not
twin wire.

Also, In the RDH4 the author shows an example for a power transformer where
in he uses twin 20 awg wire instead of 17 or 18 awg. He indicates this is to
'save winding height'. And it has fewer turns per layer in his calculations,
32 TPL vs 35 of single 20awg wire. How does one figure for this difference?

I imagine a wire table of twin wire would help but that leads to my second
question:

How do I find a wire table for twin AWG wire?
A search for 'AWG wire table' yields me a bunch of normal wire tables, but
nothing for twin wire.

Any help will be appreciated.
reply:

29AWG wire has a diameter of .0122" over the film. You can wind 78
turns per inch. Current carrying capacity at 700 circular mills is
..181Amperes.

2#29AWG in parallel is equivalent to 26AWG. You can wind 56 turns per
inch.
To determine the equivalent of two strands, go down three wire sizes
ala two strands of 15 equals one strand of 12 AWG. Two strands of 15
wound in parallel has the same DC resistance per foot etc.
If you are interested in the chart that I use for design, let me know
and I will dig it out, scan it in JPG form and send it to you.

Jerry