The AM Forum

I'm trying to search eBay for a flexible woven tube of copper or metal equivalent wire to use in making up an umbilical cord with several high voltage wires as well as coolant tubing and control wiring. This shield tube will be grounded for safety reasons and has to be very flexible. I don't seem to be hitting the right keywords. I know this stuff exists.

What would you call a thing that is like the shield of a coax cable, but is the tubing of the woven shield material by itself? I think needs it to be about 1" diameter to get everything through it.

eBay is loaded with it...search 'tinned braid'

73DG

This looks like it Patrick

http://tinyurl.com/3h7c9zo

Suggest that You contact either an aircraft products distributor or one dealing in hydraulic system parts. In aircraft systems the hoses are generally a teflon tube with a woven outer stainless steel sheath. When used as conduits, as You intend, either an AN or MS type fitting is installed or swaged on the ends which allows for screwing onto a base type receptacles and provides a point for grounding of the assembly. Depending upon the magnitude of the voltage for the inner high voltage wires, a sleeve or short length of teflon tubing is generally used in the ends to provide addition insulation at the ends in the attach fitting area. Also; using aircraft or metal sheathed lines with the appropriate end fitting, grounding  the shield at the equipment end is simplified and readily accomplished by using a matching hose size bulkhead fiiting on the unit itself and  thereby providing both for an attachment point at which the outer sheath shield and the necessary feed through point for the internal connections. If cost is a factor, try garden hose with copper braid,

The aircraft products option looks pretty good. Garden hose too.

Copper tubing braid: $2170 for a 100FT spool of Alpha 2182, 1.5" tinned copper braid. There may be a remnant on eBay if I am patient. There are also smaller sizes costing much less. I could run a single HV cable though each and bundle them. Too bad the voltage is 18-25KV, it's just too much for coax cable considering corona.

The wire could be Tevelec T0130 Corona Resistant Wire UL 3239, 16 AWG Size, 26 Strand, .097 Nominal Insulation, .256 Nominal O.D., 40,000 D.C. Voltage. They expect me to create an account and log in to see a price, that's annoying.

This gave me an idea, perhaps an automotive 'hot rod' parts supplier will have a wire mesh that goes over hoses. People use it to 'dress up' an otherwise cheap rubber hose.

Thanks!

Pat:

Just some ideas since I have done something very similar for my ART-13 using 1” wide tinned copper braid. I used Teflon coated wire for the 400 & 1200 vdc.

I have seen braid by the foot at fests quite a bit, keep looking.

Working with the ends of the braid is very easy. To terminate at the connector shell I simply shaped the braid as needed and tined it, cutting off the excess points on the end of the braid and filed it square for a nice clean job. If the tinning is thin enough you can work the end as needed. To make small through holes needed for the clamp I shaped the braid around a drill bit shank and tinned around it at the same time. Just look at the shape you’ll need before tinning.

Don’t know the exact “params” for your cooling lines, possibly the fittings and tubing used for a TIG torch would work. They are low pressure water cooled torches.

Probably not applicable here but I needed some heavy conductor for the +28vdc @ 12-20 amps. Ended up with some heavy duty speaker cable. Many fine strands wound together. (read- very flexible) and < 1v drop.

Not to be a SA but I used tinned copper braid for covering hoses on my 383 Nova. It was free, they threw it away at work and it looked FB from six feet away. If the real stuff is stainless it will be a PITA to work with and not as flexible IMO.

Just my $ 0.02

 
Best Regards
Ted / KC9LKE

How much wire do you need? I have the 40 kV rated stuff out at a transmitter site between the old beam transformers and the analog transmitters. That cable carried 22 kV at 1.6A and was just run inside regular 3/4" thick wall EMT. Analog television ant coming back and already removed the cabinets but the old transformers and conduits are still their so can pull out something for you. As far as cooling we used red radiator or heater hose between the plumbing and the IOT assemblies, never had to shield the cooling lines.
Ray F.

Hello Ted,
For my coolant lines, they are a silicon-looking type of rubber hose, no color, 3/16" ID. Bends easily like surgical tubing. Not sure what they are made of because I do not have them yet.

I don't need an all-encompassing connector at each end, just a strain relief. I can connect or disconnect things individually with their proper connectors, inside the unit, to unhook the umbilical. I'll look at those TIG cooling fittings.

Hello Ray,
I need about 15FT of the wire. It has to be about as flexible as 3/16" ID surgical tubing. Or I should say at least as flexible as an IEC type of computer power cord so that if the ends are suspended 1FT apart, it will pretty much hang down in a "U" by its own weight. It should also be corona-resistant. I was advised so, anyway. It only has to carry 100mA or less.

Thanks!

Braided Shielding, Common name "Tubular Screening", a metallic tubular braid .

How much do you need ? I have a partial spool of textile reinforced copper woven  braid loom , tubular screen type conduit . This is pretty nice stuff with textile reinforcement overlaid with a copper tinsel wrap , woven into a tube.



The flexible tubing you describe sounds a lot like Tygon tubing , a urethane type. There are suitable fittings here :http://www.matzka.com/ (http://www.matzka.com/)as well as many other fluid power products. Many TIG hoses are made with a conductor core to feed the welding current for the TIG torch. This place can be very helpful with parts:http://www.wilsonproducts.com/ (http://www.wilsonproducts.com/)

  A site for Braided Shielding or Tubular Screening products :
http://www.glenair.com/conduit/convoluted/customcable.htm (http://www.glenair.com/conduit/convoluted/customcable.htm)

We call it copper over braid here at work. Then there is snake skin which is woven nylon. Copper overbraid with snake skin over it makes for a very nice cable.

http://www.eaton.com/EatonCom/ProductsServices/AeroquipPerformanceProducts/HoseProducts/index.htm           try this    ken

  Not sure the SS hot rod(pseudo aircraft type) stuff will be flexible enough for your needs. A bit nasty to work with too. The raw ends are very sharp and tuff.

Or you can just strip some off of old coax!

Bud, did you see the lightning shot on that A380, That's our fuel control on those big Trent motors not missing a beat.

Thanks, just 15 feet if the diameter is large enough. What is the inside diameter?