does tranny winding wire shape affect performance ?

[robb]

does the cross sectional shape of the transformer winding wire
have significant performance changes compared with a round wire
winding with same crossectional area ?

by shape i mean square or rectangle or even triangular ?

thanks for any info ideas and educational comments,
robb

 

[[email protected]]

does the cross sectional shape of the transformer winding wire
have significant performance changes compared with  a round wire
winding with same crossectional area ?

by shape i mean square or rectangle or even triangular ?

Round wire does not pack as tightly (tesselate) as triangular,
rectangular or hexagonal wire might, so going with round wire does
have a cost.

I believe some applications go to the trouble of using other
crossections - the only example that comes to mind are Bittner
magnets, where the current carrying path is made of helical sheets
with holes in the them - the cooling water takes the short path
through the holes, while the current takes the longer, spiral path
theough the sheets of copper.

 

[GregS]

Round wire does not pack as tightly (tesselate) as triangular,
rectangular or hexagonal wire might, so going with round wire does
have a cost.

I am familiar with square or rectangular wire for winding voice coils, as well
as flat aluminum ribbon voice coils.

greg

 

[Paul Hovnanian P.E.]

Round wire does not pack as tightly (tesselate) as triangular,
rectangular or hexagonal wire might, so going with round wire does
have a cost.

Increased leakage flux being one cost.

I believe some applications go to the trouble of using other
crossections - the only example that comes to mind are Bittner
magnets, where the current carrying path is made of helical sheets
with holes in the them - the cooling water takes the short path
through the holes, while the current takes the longer, spiral path
theough the sheets of copper.

Large utility transformers (and generators) are wound with
square/rectangular conductors.

 

[Eeyore]

Round wire does not pack as tightly (tesselate) as triangular,
rectangular or hexagonal wire might, so going with round wire does
have a cost.

I believe some applications go to the trouble of using other
crossections - the only example that comes to mind are Bittner
magnets, where the current carrying path is made of helical sheets
with holes in the them - the cooling water takes the short path
through the holes, while the current takes the longer, spiral path
theough the sheets of copper.

Some louspeaker voice coils use rectangular wire.

Graham

 

[Allen Bong]

Some louspeaker voice coils use rectangular wire.

Graham- Hide quoted text -

- Show quoted text -

I have never seen square or rectangular enamelled wires. Are the
corners rounded?

Allen

 

[Eeyore]

I have never seen square or rectangular enamelled wires. Are the
corners rounded?

I haven't seen it on a reel so I couldn't tell you. I imagine it might
well be.

Graham

 

[Phil Allison]

"Allen Bong"

" I have never seen square or rectangular enamelled wires. Are the
corners rounded? "


** Well, with the smaller gauges at least and to the un-aided eye - the
corners look sharp.

Under sufficient magnification, they may appear quite rounded.

Got any more ambiguous questions ?



....... Phil

 

[John Popelish]

I have never seen square or rectangular enamelled wires. Are the
corners rounded?

Yes. See corner radius spec:
http://www.mwswire.com/square.htm

 

[Rich Grise]

does the cross sectional shape of the transformer winding wire
have significant performance changes compared with a round wire
winding with same crossectional area ?

by shape i mean square or rectangle or even triangular ?

thanks for any info ideas and educational comments,

I don't know how significant - the area of a, say, 2mm square
is almost 4 mm^2 (a litle less because of the rounded corners),
but round wire 2mm diameter has an area of pi * r^2, or 3.14
mm^2, which actually does look fairly significant.

Bottom line, you can get more copper into the winding window.

Cheers!
Rich

 

[Clifford Heath]

Round wire does not pack as tightly (tesselate) as triangular,
rectangular or hexagonal wire might, so going with round wire does
have a cost.

When the new Australian Synchrotron (6km from here) was nearly finished,
they had an open day, and I noticed that many of the beam-bending
electromagnets used square wire, or square tube perhaps, perhaps 10mm
on a side, with rounded corners. Each wrap was separated by a 10mm air
gap as well, and I think adjacent turns were also separated. All
presumably for cooling while 1000's of amps were pumped through them.

Clifford Heath.

 

[JosephKK]

When the new Australian Synchrotron (6km from here) was nearly finished,
they had an open day, and I noticed that many of the beam-bending
electromagnets used square wire, or square tube perhaps, perhaps 10mm
on a side, with rounded corners. Each wrap was separated by a 10mm air
gap as well, and I think adjacent turns were also separated. All
presumably for cooling while 1000's of amps were pumped through them.

Clifford Heath.

Could well be tubing with chilled water, or LN2 pumped through them.

 

[JosephKK]

I don't know how significant - the area of a, say, 2mm square
is almost 4 mm^2 (a litle less because of the rounded corners),
but round wire 2mm diameter has an area of pi * r^2, or 3.14
mm^2, which actually does look fairly significant.

Bottom line, you can get more copper into the winding window.

Cheers!
Rich

And for some applications more, copper surface area which can be
important. Also at a 4 to pi ratio.

 

[[email protected]]

does the cross sectional shape of the transformer winding wire
have significant performance changes compared with  a round wire
winding with same crossectional area ?

by shape i mean square or rectangle or even triangular ?

thanks for any info ideas and educational comments,
robb

No, certainly not enough to make your own round wire square. But for
the big boys (GE, ConEd, etc.) where a 2% return in efficiency is the
difference between howling at the moon or a big fat christmas bonus
then, yes.

I doubt any real cost benifits could be found in anything under 10
kilowatts in size. Are you trying to wind a 50 kilowatt toaster?
trading silly questions here.

 

[[email protected]]

When the new Australian Synchrotron (6km from here) was nearly finished,
they had an open day, and I noticed that many of the beam-bending
electromagnets used square wire, or square tube perhaps, perhaps 10mm
on a side, with rounded corners. Each wrap was separated by a 10mm air
gap as well, and I think adjacent turns were also separated. All
presumably for cooling while 1000's of amps were pumped through them.

Spacing the turns by the wire dimension maximises the maximum
impedance of singe layer coil - a bigger gap decreases the inductance
more than it decreases the parallel capacitance and a smaller gap
doesn't increase the inductance as much as it increases the parallel
capacitance.

I'd expect water-cooled coils to use the Bitter geometry - a spiral
ribbon to carry the current between two coaxial non-conducting tubes
to carry the water with holes through the ribbon so that the water
could flow straight along the tube,

http://en.wikipedia.org/wiki/Bitter_solenoid

 

[robb]

No, certainly not enough to make your own round wire square. But for
the big boys (GE, ConEd, etc.) where a 2% return in efficiency is the
difference between howling at the moon or a big fat christmas bonus
then, yes.

I doubt any real cost benifits could be found in anything under 10
kilowatts in size. Are you trying to wind a 50 kilowatt toaster?
trading silly questions here.

No, just curious....
when i read about tranny discussion and how or why someone might
go to the trouble of solving various problems in tranny winding ?
what kinds of problems are there and what are those solutions ?

In this case it might have been better to ask what parameters of
transformer operation are affected by the airgap between windings
and or how the windings are laid out including the performance
and parameters affected by the width anf height of the bobbin
that is frequently used in the mass produced trannies ?

Another curiousity is that the windings on transformers i have
opened seem quite sloppy wound and not evenly placed and i would
have thought that *even/neat* winding would have been a large
factor in transformer performance ? but maybe not ?

I would likely only be able to play with flatened / rectangular
or ribbon style wire anyways, as i imagine i would be
constructing a rather crude jig to shape the wire and a nicely
square wire would probably require something a little more
sophiticated than i would build. ( ie. steel bushings for rollers
pins with an adjustable gap)

thanks for the responses,
robb

 

[[email protected]]

On Mar 7, 8:50 am, "robb" <[email protected]> wrote:

Another curiousity is that the windings on transformers i have
opened seem quite sloppy wound and not evenly placed and i would
have thought that *even/neat*  winding would have been a large
factor in transformer performance ? but maybe not ?

"Even/neat" looks nice, but only works with a few layers of fairly
thick wire.

I would likely only be able to play with flatened / rectangular
or ribbon style wire anyways, as i imagine i would be
constructing a rather crude jig to shape the wire and a nicely
square wire would probably require something a little more
sophisticated than i would build. ( ie. steel bushings for rollers
pins with an adjustable gap)

The layer of insulating enamel on the wire isn't going to survive this
kind of treatment. Figure on re-enamelling the wire after you've
reshaped it.