Phil,
If all the strands were loose and not all soldered together I would say go
ahead and crimp. But with all the wires soldered into a solid mass I think
the crimping would be like trying to crimp to a large solid wire. I recall
that is not an accepted practice.
I think you have no option but to solder the Litz to the terminal but that
will focus bending, and breakage, at the wire to solder transition. If the
remain Litz is secured and there is little vibration probably ok.
Now all that is my guessing to fill in the blanks I never knew or forgot.
:-(
Bob K
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Nutting, Phil
Sent: Thursday, October 22, 2015 5:15 PM
To: [log in to unmask]
Subject: Re: [TN] to solder or not to solder Litz wire in crimp lug
Bob,
Yes, the stripping is accomplished by the tinning process as it "burns off"
the Nylon thread serve and the enamel coating on each starnd. Chemical
stripping brings in a whole bunch of issues we chose not to play with.
Depending on the Litz wire and the frequency range of system operation the
individual strands of wire could be as small as 40 to 48 gauge and lots of
them.
-----Original Message-----
From: Robert Kondner [mailto:[log in to unmask]]
Sent: Thursday, October 22, 2015 5:09 PM
To: 'TechNet E-Mail Forum'; Nutting, Phil
Subject: RE: [TN] to solder or not to solder Litz wire in crimp lug
Hi,
I would think you need to strip the Litz pror to crimping. The stripping is
accomplished, I assume, in the tinning process.
If you are tinning and stripping in one fell swoop in a solder pot then the
Litz would come out as a rigid piece, not the best candidate for crimping
into a terminal.
So I probably missed something but how are you stripping the Litz?
Chemically? How many fine strands are we talking?
Bob K.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Nutting, Phil
Sent: Thursday, October 22, 2015 4:30 PM
To: [log in to unmask]
Subject: [TN] to solder or not to solder Litz wire in crimp lug
Esteemed colleagues,
For our high voltage transformers, many are wound with Litz wire (see links
below for more info). To make an electrical connection we tin the wire ends
in a solder pot. From there the tinned wire may be inserted and soldered
into a circuit board or a ring lug is crimped onto the tinned end.
So here is the "discussion" within our group. I have fought (and won) to
eliminate crimping and tinning of ring lug terminated regular stranded or
solid wire. The theory being that if the crimp lug has been properly sized
to the wire and the tool used is properly calibrated for the lug/wire being
crimped that the crimp forms a gas tight seal and further treatment such as
soldering it is unnecessary or even detrimental. I have supporting
documentation from Amp for this statement.
Ok, now enter tinned Litz wire. Does the properly sized lug/wire
combination require soldering after crimping? Some here say it must be
soldered the argument being the solder is softer than the copper and
therefor there will be cold flow. Also if it heats up the solder could
melt, but if that happens there are bigger problems than just the
crimp/solder joint, IMHO. I believe crimping and tinning of Litz is not
necessary, simply crimping is sufficient.
Opinions?
Reference links;
https://en.wikipedia.org/wiki/Litz_wire
https://www.newenglandwire.com/en/products/litz-wire-and-formed-cables/types
-and-constructions
Phil Nutting | HVP Development Engineer | Excelitas Technologies Corp
Lab: +1 978.224.4332 | Office: +1 978.224.4152
35 Congress St, Salem, MA 01970 USA
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www.excelitas.com<http://www.excelitas.com/>
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