On 30 Apr 2013, at 11:29, Tony Renshaw wrote:
> I would like to seek advice regarding electrical connectors. I recall that the
better ones were translucent and have dual crimps
Tony - what you are seeking is a crimp with an extended metal barrel which grips
the wire insulation when crimped as well as the conductor.
If the insulation is not gripped firmly by the crimp, vibration or flexing can
cause strands of wire to fail from fatigue, similar to (but much slower in
action
than) an unsupported solder termination. The plastic part of an inferior crimp
appears to crush down and grip the insulation, but the grip is poor and can
soon become non-existent as the plastic relaxes back to its pre-crimped state.
That relaxation is accelerated by heat.
The only reliable term I have found to identify the good crimp terminals is
"PIDG"
which I think stands for "pre-insulated diamond grip" although that does not
convey much about the specific features we want. There are others but it's
hard to know if they are the desired type without having one in your hand!
If the insulation is translucent it does let you see at a glance if the terminal
has the required extended sleeve, but it's easy enough to visually check the
ones with opaque insulation too.
In my searches for the several different types of crimps I need* I have used
various
suppliers in UK for crimp terminals such as Parts for Aircraft, RS, & Farnell.
The types stocked by each don't seem to be very consistent and I often
have to look quite carefully at the online data sheet to ensure that I'm
ordering
what I want.
Finally, a ratchet crimp tool is excellent for making sure that all crimps are
fully compressed. You do have to remember which way round the crimps fit in it
- the inner and outer parts of the crimping die are different shapes and
although
the result might look OK, the wire will pull out quite easily.
I'm sorry that despite the length of my post, I can't give advice about
suppliers
in USA, but doubtless others can do that. I hope some of the above may help
you when trawling through suppliers' part listings.
*mixtures of: red (16-22AWG) and yellow (10-12 AWG) with 6.35mm blade, 3mm ring,
3.5mm ring, 4mm ring, 5mm ring, 6mm ring, 8mm ring, 10mm ring. this is because
many of my electrical items have screw terminals rather than blade connectors.
in friendship
Rowland
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