Connect litz wire to copper blade

[Michael@VAC_KB-PM]

Hi,
I'm trying to find a way to connect a AWG24 litz wire to a copper current
blade 4.5 x 0.75 x 0.1 inch. Soldering by using a standard solder bolt doesn
't
work properly because of the copper heat conductivity/capacity.
I wonder if resistance welding or soldering might be a possible way?
The process should be capable for large scale production.
Appreciate your ideas!
Thanks, Michael

 

[Winfield Hill]

Michael wrote...

I'm trying to find a way to connect a AWG24 litz wire to a copper current
blade 4.5 x 0.75 x 0.1 inch. Soldering by using a standard solder bolt
doesn't work properly because of the copper heat conductivity/capacity.

We treat the litz-wire ends in a solder pot. It's necessary
to coat the litz wire first with flux, no success otherwise.
Once the litz is tinned you can use conventional methods...

Thanks,
- Win

 

[Gary Coffman]

On Wed, 27 Aug 2003 12:24:48 +0200, "Michael@VAC_KB-PM" <520036845880-0001@t-online.de> wrote:

Hi,
I'm trying to find a way to connect a AWG24 litz wire to a copper current
blade 4.5 x 0.75 x 0.1 inch. Soldering by using a standard solder bolt doesn't
work properly because of the copper heat conductivity/capacity.
I wonder if resistance welding or soldering might be a possible way?
The process should be capable for large scale production.

Each strand of Litz wire is separately insulated (that's what makes it
Litz wire). You have to strip that insulation off before it will take solder.
There are chemical dips you can use to do this with some insulation
formulations. Consult the wire manufacturer for the recommended
stripping method.

To handle the heatsink issue, use a torch (or hot plate) to preheat
the copper before attempting to make the joint. The whole thing
doesn't have to be brought to soldering temperature. It just has to
be hot enough to reduce its ability to sink soldering heat away from
the joint. You don't want to heat it so much that it oxidizes. Since
heat flow is proportional to the fourth power of temperature difference,
250 F should be plenty of preheat.

Gary

 

[Stephen (Despammed)]

"Gary Coffman" <ke4zv@bellsouth.net> wrote in message
news:0ubpkv8c0ok35u10h85t9ekc1lb17srthv@4ax.com...

Each strand of Litz wire is separately insulated (that's what makes it
Litz wire). You have to strip that insulation off before it will take
solder.
There are chemical dips you can use to do this with some insulation
formulations. Consult the wire manufacturer for the recommended
stripping method.

Since I didn't have a clue as to what Litz wire was, here's more than you
ever wanted to know about Litz wire:
http://www.mwswire.com/litzmain.htm
The term litz wire is derived from the German word litzendraht meaning
woven wire. Generally defined, it is a wire constructed of individual film
insulated wires bunched or braided together in a uniform pattern of twists
and length of lay.

The multistrand configuration minimizes the power losses otherwise
encountered in a solid conductor due to the "skin effect", or the tendency
of radio frequency current to be concentrated at the surface of the
conductor.

In order to counteract this effect, it is necessary to increase the amount
of surface area without appreciably increasing the size of the conductor. It
is also essential to position each individual strand in the litz
construction in a uniform pattern moving from the center to the outside and
back in a given length.

Even properly constructed litz wires will exhibit some skin effect due to
the limitations of stranding. Wires intended for higher frequency ranges
require more strands of a finer gauge size than litz wires of equal cross
sectional area but composed of fewer and larger strands.

Polyurethane is the film most often used for insulating individual strands
because of its low electrical losses and its solderability. Other
insulations can also be used. Litz wires are generally further insulated
with a single or double wrap or serving, of a textile-typically nylon-but
are also available unserved.

r/

Steve

Bremerton, WA