enameled copper wire size? - Page 1
Forum section: electronics / beginners

author: alin_im
author_rank: Regular Contributor
timestamp: August 04, 2015, 09:38:02 pm
content: Hey guys,Noob question: What is the usual / most use size for enameled copper wire used for communication/rf and also common coils ?I know that I can calculate my inductance using the formula with the diameter, current and number of turns.I would like to buy 2 different sizes a 1mm and 0.5mm to be easier to calculate. I think the 1 mm I will use it for few number of turns and the 0.5 for larger number of turns.What do you think what do you advise me to buy for my purposes, also any ideas for some basic coil cores (there are so many on the market and i feel kind of overwhelmed) ?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 04, 2015, 10:10:28 pm
content: For what frequency, power level, operating temperature, required efficiency or Q factor, and coil/antenna design?Nice thing about smaller sizes is you can always use more, doubled up, if you need more ampacity or higher Q.Tim

author: alin_im
author_rank: Regular Contributor
timestamp: August 04, 2015, 10:24:42 pm
content: Quote from: T3sl4co1l on August 04, 2015, 10:10:28 pmI do not have a project now that I am working on, I am just asking because I want to have some coil wire for my lab. To vaguely answer your question I think I will you use it for a frequency between 10 - 110 MHz and a Power between 4 - 40 W, the rest I can not tell you to much...

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 05, 2015, 01:41:15 am
content: Hmm, I'd go with 0.5mm, or less. 1mm is awfully coarse, to the point that it's hard to bend into small coils by hand (you'll need to pinch and crimp it with pliers all the way).Tim

author: vk6zgo
author_rank: Super Contributor
timestamp: August 05, 2015, 12:16:54 pm
content: Back the old days in Oz,we were subject to multiple wire gauges,AWG (B&S back then),SWG,& sometimes,metric.Here is an interesting website:-http://www.dave-cushman.net/elect/wiregauge.html

author: alin_im
author_rank: Regular Contributor
timestamp: August 05, 2015, 01:02:53 pm
content: Thank you for your replies I think I will buy 0.8 and 0.5 atm. Any ideas about ferrite coresSmall to medium ones not the cores for transformers. What is the diff between the ring ones and the tube ones ? Any useful article to read about ?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 05, 2015, 06:35:29 pm
content: Again, for what purposes? Inductors (anything that must store energy or carry unbalanced DC) are best wound on gapped shapes, or powered iron. Chokes (that don't have to carry unbalanced DC, and should have a high impedance or low magnetizing current -- so also, most transformers) are best on ungapped or toroid ferrites.FBs for EMI depend a bit on the application. There are a few grades of material for different frequency ranges, and besides getting one big enough to fit over your wires or cables, you have some choice of length and outer diameter, which control the amount of impedance, and the shape of the impedance peak.There's lots of good documentation onFair-Rite,Magnetics,Micrometalsand so on.BTW, you can always get EMI cores at the usual distributors (like Mouser, Digikey, Farnell, etc.). Toroids aren't usually well stocked, but you can usually find useful ones (yes, you'll have to shop around, and go back and forth between the manufacturer's listings and the supplier's stock to find parts that exist..). Shapes (E, RM, potcores, etc.) are now being carried, as well as the bobbins and other accessories needed to use them!Powdered irons still lag behind, and are available from the traditional distributors (Amidon Corp, Dexter Magnetics, Adams Magnetic, Elna Magnetics..). YMMV for international shipping/distributors.Tim

author: gildasd
author_rank: Frequent Contributor
timestamp: August 05, 2015, 07:17:00 pm
content: Quote from: T3sl4co1l on August 05, 2015, 01:41:15 amWorked on main coils of a big DC motor last week... 150Kg of copper 6cm wide by 0.1cm thick - per magnet!Would that actually emit a useful RF signal?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 05, 2015, 07:53:27 pm
content: Sure! In what configuration?Inside the motor, not much will escape the enormous steel core and casing. But if it's being powered by an electronic controller (a DC type could be fairly quiet actually, but the typical VFD, for AC induction motors, doesn't usually have much filtering), the wires leading up to it can broadcast quite a mess of noise.If you cracked open the motor so the field coils were exposed (lots of magnetic field going through air, instead of shunted through steel), it still wouldn't be a very good antenna at low frequencies, because it's simply not large. In the context of RFID... I don't know why you'd ever want to do RFID at 60Hz (or how you'd be able to pull off the receiver), but such a beast would have pretty good near-field range, considering.If you took that strap out of the motor and hung it up, it would make a fine antenna. As fields are concerned, rectangular conductor will look, very roughly speaking, like a wire of equivalent diameter, say D = sqrt(L * W). Or that's about what I would guess, anyway. The equivalence being in terms of losses / Q factor and antenna bandwidth for common configurations (say for a dipole).Tim

author: German_EE
author_rank: Super Contributor
timestamp: August 05, 2015, 08:58:01 pm
content: For winding coils on formers I normally use 0,5mm and 'loose' coils are constructed using 1mm wire. Transmitters are however an exception and here I use 2mm wire which is good to 100W.

author: alin_im
author_rank: Regular Contributor
timestamp: August 05, 2015, 09:37:07 pm
content: Quote from: T3sl4co1l on August 05, 2015, 06:35:29 pmi was thinking about getting some powdered iron (corehttps://www.google.ro/search?q=powdered+iron+core&rlz=1C1CAFA_enRO607RO607&biw=1242&bih=606&source=lnms&tbm=isch&sa=X&ved=0CAYQ_AUoAWoVChMI8pD53_KSxwIV4inbCh33MwJ4#imgrc=rSOee-HdWJiLHM%3A) for filters/tunning circuits

author: TimFox
author_rank: Super Contributor
timestamp: August 06, 2015, 04:50:49 pm
content: I was installing some high-power equipment in the UK a few years ago, and the local guy asked me if "6 mm" wire was sufficient for the mains connection. I quickly converted that mentally to 0.25 inch diameter (roughly 2 or 3 AWG) and said that was plenty. It turns out he meant "6 mm^2", the standard nomenclature there, which was only 2.8 mm diameter, or 9 to 10 AWG. It could have been worse, we could have been discussing circular mils.