JX Thermocouple wire... Flex application

Don't know about thermocouple cables, but Igus do a pretty good range (I use them for both 'energy chains' and cable to go in them).

Another alternative is to use converters at the business end, and have a more robust signal (e.g. 4-20mA) back to the instrumentation.

I've been looking through the selection of wiring that IGUS has.. for the same machine(s) actually, if i had a budget that would support more stuff, i would go the route of a converter, but i've got to run as cheap as possible right now, AND i really don't want to add further complexity into the system for my maintenance crew to have to deal with @ 2am in the morning :)

I appreciate the thoughts though!

-Nate

Try standard spiral phone cord... the kind that goes from the base to the hand set. The wire is wound around a nylon core. You know how phone cords are, you could swing the base over your head all day & it would still work unless you ruin the connector or cut it.

I used to use them on a 500⁰ f flying press the stroke was 30" & 20 strokes per minute.

There is a wide array of connectors, our favorite was a locking swing over cover. It can be changed out in about 30 seconds, nice terminal & gold contacts

We used various Honeywell udc 3000 & various watlow hi limits controllers...

Agree curlies are very good - last week did a repair on a sample changer I installed in 1988 (fault not related to the cord) - admit it only does about 1 stroke an hour, but its been running more-or-less 24/7 for 21 years.

... but 'phone cord ain't thermocouple wire!

I know that, but it depends on the amount of error that is acceptable

For hi limits you want to shut things off when you are well above normal temp, but before flames start shooting out places they shouldn't

The application I was discussing in#5, we couldn't tell the difference between thermocouple wire, copper or tinned [tryed em all side by side]. The hot part was 2-40"x30" aluminum platens, which had cartridge heaters. Originally there were fancy bayonet couplings & special watlow j type thermocouples. We got better results using solid bi-metal thermocouple wire twisted together [which makes a thermocouple] & plain bolting it to the side of the platens in a easy to access location. We weren't so much interested in completely [calibrated] accurate temp readings, but repeatability & speed of repair. We had the same 24/7 issues, @ 3am you don't really want the techs to have to think too hard, just get things running.

I seen quite a few applications using shielded #20 stranded copper wire back to plc's in food plants, the read outs ended up being for reference, since keeping them calibrated to ISO standards is cost prohibitive.

Switching to RTD's allows more stability & flexibility, most controllers support them these days...

I guess it depends on how tightly this 'high limit' needs to be toleranced. There's mention of a process & a process controller.

Agree that if it's just 'Hell, it's hot - switch it off!' then more-or-less any old cable will do.

Google "stranded thermocouple extension wire" and you will probably be able to find some manufacturers.

I'd give the folks at Omega a call and see if they can help

Cheers

Martin

Fluropolymer insulated compensating cables stand flexing better as they reduce friction and do not 'Catch against each other or the tray in flexion.

http://www.kellysearch.com/us-product-94410.html

http://www.indiamart.com/rajsav/cables-wires.html

http://search.elecdir.com/index.html?data=thermocouple_extension_compensating_cables

http://www.ddacables.com/katalog/04_kompenzacni.php

Hello all , I would like to add that the people at Omega have been very helpful to us at my plant. I am senior electrician at a Copper Foundry in upstate NY. I prob have around 50 thermocouples at various locations at several different Melters and casting furnaces. I use mostly J-K type. As you know the connecting wire for each thermocouple must be a metal-to-metal match in order for it to operate properly. I have used in short spurts a R type wire with a K type thermocouple with sucess (with in 5-10 degrees C ) accuracy. I am pretty sure the last time I checked in with Omega, Last week I think, that they have a flexible K wire that should fix your problem I just had to replace the multi pair thermocouple wire at the Otokumpo furnace recently and I got it from Omega. Hope this helps.

Are you still running with this problem?

Did you ever try to use the Mineral Insulated Cable based thermocouple sensors?

Those are a pair of thermocouple wires into the stainless steel sheath. There is a big variety of external diameters and you can chose them at your convenience.

Try to find out more about with WIKA Instruments: http://www.wika.com/WIKAWeb/Sales/Default.aspx under "Electrical temperature distributors" option.

I am sure this is the solution you need.

I am working for WIKA Argentina (10 years of expirience on customers needs) and we produce those kind of sensors for our local market.

For any more info, please, contact me here or on sbeniashvili@wika.com.ar

With Best regards,

Simon

To increase fatigue resistance, you might try smaller diameter extension wires, If the flexing is always in one direction, you might try ribbon extension wires. This will lower the maximum stress in the wire for any bending radius.

HHmm...

I am still running with this problem... kinda. I have "solved" it temporarily by swapping out to some spare 4-pair extension wire that we had in the back of the maint dept, however that is not solving the root problem.

I will give the flouropolymer search a shot, see what i can find there. I may also end up going with single-pair wires, as that will obviously help get the OD down, which will lead to a more flexible cable-set.

I didn't even *think* to do the basic "stranded thermocouple extension" search... *d'oh*...

I will take all your suggestions and run with them for a while, i will report back as I obtain some findings! Thanks!

-Nate