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Test Equipment Anonymous (TEA) group therapy thread

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factory:
Another grey box* red box (for a change) arrived today.  8)


*I often get the comment "not another grey box" when large parcel(s) arrive.

David

mnementh:

--- Quote from: AVGresponding on July 01, 2022, 05:22:49 pm ---
--- Quote from: mnementh on July 01, 2022, 04:28:18 pm ---

The wedge does form if you do the 2nd crimp far enough away; it forms between the 2 crimps. A mm wide and deep (less, really) is all the wedge needs be to provide more than adequate mechanical strength. When I talk of the 2nd crimp being "for good measure" it is to increase the contact area under compression for lowest resistance, not mechanical strength.

These are not brake cables or the like; mechanical strength does not need to be that much in engineering terms to be stronger than any mechanical stress it should ever experience.   mnem    :blah:
--- End quote ---

You haven't seen how some "engineers" rag on cables connecting big batteries in big strings... you'd think the prospect of instant death if there's a serious short would moderate their behaviour, but as the old saying goes "familiarity breeds contempt".

If you do the arithmetic, you'll see that even a single crimp will have more surface contact area than the cable CSA. I'm not saying it's inherently bad, I'm just saying I prefer the guaranteed mechanical strength over the possible few nano-ohms difference a second crimp makes.

Mostly these things will only make a difference in edge cases; I routinely "crimp" 10-95mm2 lugs with my trusty 2PH and a hammer (only if I don't have a proper crimper to hand and it needs to be done NOW. Bigger than 95mm2 and I need a hydraulic crimper which I don't have, so those have to wait until it gets hired). Haven't burned any buildings down yet.   ???
--- End quote ---

I think we've both come to a similar understanding of what's important when making heavy-ass cables (heavy ass-cables def need to be made for mechanical strength FIRST  >:D) ; just coming at it from different directions. ;) I spent a fair bit of time doing scale RC drag racing, where fractions of a ohm do make a difference you can see on the clock, then working on big forklifts as a young mechanic... so I'll just say it can matter.  :-//

When you say "rag on cables", I'm guessing you mean something different than I would? Over here, to "rag on" something means to "frequently, repeatedly denigrate" whatever it is... ie "In the TEA thread, we always rag on RIFAs and tants!"

So from the context, I'm guessing you mean something like "to put it on carelessly" or to "assemble poorly and without regard for proper procedure"...?  :o

mnem
*luggable... barely*

Zucca:
Yes I was right, we can talk for pages and pages about crimping a big cable.
This is the only place that can happen so flawlessly.

Fantastic performance gang! Many thanks!

My major concern is now the power company: will they let me interconnect my solar/battery system IF I do not plan to sell back the energy to them?
All what I need is to stay passive as I am now....no change in my current contract.
I sent already an email... I am scared to read their response.

Robert763:

--- Quote from: factory on July 01, 2022, 07:27:24 pm ---Another grey box* red box (for a change) arrived today.  8)


*I often get the comment "not another grey box" when large parcel(s) arrive.

David

--- End quote ---

Racal SA 540 Universal counter
Edge lit readout
£38

tautech:

--- Quote from: Vince on July 01, 2022, 02:01:39 pm ---Forgive the dumb question, but why not just put that tool in a vice to squeeze it smoothly instead of hammering it ?!  :-//
The smooth progressive action of the vice would be kind to the lug wouldn't it.

I mean a real big/full size garage vice of course, not the tiny vice we use in the lab, that goes without saying ! ;D

--- End quote ---
With a little care you can indeed make very serviceable crimps in a vise if you know how.
Not so much with the smaller cable sizes however in a permanent installation where there will be zero vibration or rarely a need to disconnect it, then bucket type lugs, those without a opening at the bottom of the bucket then soldering on crimps works just fine however a cleaner job is done with a Propane torch rather than Oxy/Acetylene.

Crimps in the vice with commercially or homemade lugs really need a reasonably heavy wall lug to withstand the compression as only 2 sides of the crimp are contacted on.
First you need a crimp that well matches the cable size and then the Hex head of a bolt or stout nut for just one of the Hex faces to be squeezed into the side of the barrel of the crimp to leave a deep rectangle pressed into the crimp.
I've used this method with 100% success over many decades on heavy welder leads and with a couple of layers of shrink sleeve for strain relief it's a quick solution if you don't have some blowtorch handy or your sparky mate with the good crimpers has gone AWOL.

Edit
However care must be taken where one might do such non-standard procedures so to properly consider the risk to life, limb or property.

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