molded vs wirewound phenolic inductor? - Page 1
Forum section: electronics / rf-microwave

author: coppercone2
author_rank: Super Contributor
timestamp: December 09, 2024, 08:59:34 am
content: I see an option for buying inductors. The bournes datasheet says Molded is "high q" and the wirewound does not mention Q and mentions power supplies.These are 'dielectric core' through hole parts (NOT FERRITE)The SRF and Q appear the same for the minimum parameters in the datasheet.Does it matter at all? Does the molded one really have a higher Q, sometimes? I figure it would be like, advertised.

author: mtwieg
author_rank: Frequent Contributor
timestamp: December 09, 2024, 02:20:47 pm
content: "high Q" is meaningless without actual numbers."Molded" often refers to a process for forming cores somewhat similar to injection molding. This usually refers to permeable cores, AFAIK phenolic cannot be molded.What specific series of inductors are you looking at? I'm guessing 9230?

author: coppercone2
author_rank: Super Contributor
timestamp: December 09, 2024, 09:31:37 pm
content: https://www.digikey.com/en/products/detail/bourns-inc/9230-02-RC/3779351https://www.digikey.com/en/products/detail/bourns-inc/8230-02-RC/774700the spec is the same, the description and construction is different.I am buying assortments for a inductor kit, I don't know which I want. The one that looks like a composite resistor is smaller, and looks cooler, and makes claims about higher Q.I associate wire wound with higher surge resistance. But it says nothing about that.

author: mtwieg
author_rank: Frequent Contributor
timestamp: December 10, 2024, 12:46:27 pm
content: If all the specs (ESR, Qmin, SRF, Isat, etc) are identical between the two series, then I'm certain they are effectively the exact same parts (same windings and cores) but with different outer skins (conformal coat vs molded). Seems unlikely that this would affect performance except for SRF, but even SRF is the same in the datasheet. If there's any difference, you'd have to find out for yourself via measurement of actual components.

author: coppercone2
author_rank: Super Contributor
timestamp: December 10, 2024, 09:52:09 pm
content: I think the one with wire can take more surge. I think it ends up being looser, especially when its over heating hard. I think this means it can maybe deform instead of ripping. If its molded in there, it might get yanked apart by well anchored sections during spot heating, but if its wound, it might like delaminate and spread the stress along the coil.I put air wound steel coils under heavy over load, and its weird what happens when they get hot, they seem to contract in places, expand in others, and bend in odd directions. But this was with DC. I don't know what a big RF energy pulse would do. Probably weird. probobly as soon as something starts necking, that area of the coil would go crazy. Not sure what copper would do, especially if its annealed.But at this point you would have a really messed up inductor, but it might still kind of work lol.I have seen inductors bubble up too, smt ones, when they get over loaded, you get a bump in the middle (tries to turn into a sphere I guess, or its maybe a air bubble, i don't know )

author: coppercone2
author_rank: Super Contributor
timestamp: December 16, 2024, 08:34:48 am
content: rather then starting a new threadWhat is the core from iron core inductors made of? If I wanted a value between what I have.Are they actually pure iron solid rod, or typically a cheaper material? The vendors don't say much.Getting iron rod is actually kind of expenisve. They don't make it from wire do they? Or is it called 'soft iron' rather then pure iron? But for serious electrical components... I figure they use pure iron??

author: Kean
author_rank: Unknown
timestamp: December 16, 2024, 09:27:57 am
content: Soft iron (annealed) which doesn't stay magnetized when the field is turned off.Or powered iron (typically iron oxide particles + binder) that are pressed into shaped, but without the ceramic that would be included in ferrites, or need for high temperature. These are generally the cheaper option.More info can be easily be found online, e.g.https://en.wikipedia.org/wiki/Magnetic_coreor look at the app notes and tech docs at supplier websites.

author: coppercone2
author_rank: Super Contributor
timestamp: December 16, 2024, 09:41:05 pm
content: does it have a designation like copper or brass might, i.e. like "brass alloy 360" or "C11000"It seems nebulous. Copper is like well organized and modern, while iron seems feudal in nature

author: Kean
author_rank: Unknown
timestamp: December 18, 2024, 02:20:26 pm
content: There are a whole bunch of alloys that can be used (some mentioned in the wiki article), but you can also use "pure" iron ("pure" being high purity Fe, but not 100%).As I understand it, "pure" iron is not going to be readily available from a place like the local metal supplier in your country. It has limited use except in specialist applications. Practically all industries would use a ferrous alloy (e.g. carbon steel) to get better mechanical or chemical properties.I don't really understand your needs/requirements. As usual, you are being incredibly vague and asking questions that can be easily answered with just a little research.Maybe you should reach out to an inductor manufacturer like Coilcraft or Wurth. They may even have an off the shelf part you can start from.You could also try a specialist supplier like Sigma Aldrich who stock various iron and ferrous alloy powders. Maybe solid material as well, I don't know.I've seen "99.99%" cubes for sale on AliExpress.

author: coppercone2
author_rank: Super Contributor
timestamp: December 18, 2024, 02:30:51 pm
content: I mean it has to have more use them some exotic superalloy steels but they are still named 'professionally'.I thought the application is pretty clear, rods for winding between value axial inductorsthat seems rods between 1-5mm for a reasonably normal looking PCBI got all the values of iron and phenolic through hole inductors they have at distributors (some 100+ values), and if I get some rods and wire I can make anything in between. Air core is easy, it looks like fiberglass rod will work just fine. Metal is not so easy because everyone has their own sauce. Ferrite it looks like you can get the 'base model' where it might not be as nice as a proprietary modified ferrite, but it should be OK.I guess the mechanical engineers are just too smart to buy unknown composition alloys, unlike dummy electrical engineers that buy the mystery meat. makes me think it goes with the territory of how cheap they are lol. Looks good, they call it 'meat'. The ME is gonna get his Rene 41 and the EE is gonna get "iron composition'.You kno what its like, hot dogs. Made with "magneticmeat product'.

author: kleiner Rainer
author_rank: Regular Contributor
timestamp: December 20, 2024, 11:08:14 am
content: Coppercone,if you want specs, you have to look for the right manufacturer:https://www.micrometals.com/https://www.micrometals.com/products/materials/rf/And if you want to design your own inductors, there is (apart from the tools Micrometals provides) this one written by hams from Germany:https://www.dl0hst.de/mini-ringkern-rechner.htm#enGreetings,Rainer DG1SMD

author: coppercone2
author_rank: Super Contributor
timestamp: December 20, 2024, 02:38:59 pm
content: wow for some reason carbonyl iron took me 10 minutes to find even though it has a wikipedia page.talk about SEO spam from medical stuff!https://en.wikipedia.org/wiki/Carbonyl_irongoogle would make you think its either a pungent liquid or some kinda tabletsit appears to be precipitated iron, similar to how some nano materials are formed.So I wonder if all these coils are actually powered iron, instead of solid iron. Iron and powdered iron have different listings on digikey. Not much for powdered iron axial. but I wonder if in fact its powdered iron. I thought iron might actually mean... solid iron.DO you think this is powdered/carbonyl iron?https://www.digikey.com/en/products/detail/delevan/1641R-102K/1115257There is a series of these cores.This oddball one is listed as powdered ironhttps://www.digikey.com/en/products/detail/gowanda-electronics/MLRF17S101K/21388973the link is broken so you need to use manufacturerhttps://www.gowanda.com/product/mlrf17s101k/They write IRON and POWDERED IRON in their datasheets between Delevan and Gowanda.SO I am pretty sure the Gowanda is carbonyl iron or some derivative.But what is the delevan? It looks like the spec on all of them is the same (even ferrite)You would need to see the different curves.From what I understand the difference between Ferrite and Iron (i don't know which form) is that the saturation will not be abrupt under high currents, so the iron will have a hill response and the ferrite will have a cliff response. but what is the difference between iron and powdered iron? Powdered iron will have a gentle hill (cow) and iron will have a break your leg hill (deer) and ferrite will have a fall to your death (mountain ibex) ? and nanocrystaline will support passage of a hippopotamus?

author: coppercone2
author_rank: Super Contributor
timestamp: December 21, 2024, 09:06:49 am
content: does anyone know what the leads of a wound varnished phenolic inductor might be made out of?It does not feel like copper. it is pretty springy. Completely non magnetic (tested with giant magnet)https://www.digikey.com/en/products/detail/bourns-inc/4611-RC/3193273I thought it would be copper. Bends easier then the same size brass rod I have, but it feels really springy. Its not like any resistor leads for a similar size. It makes a noise when you flick it. It looks kind of coppery when I cut it, but I also think it looks 'granular' like if you rip aluminum. Compared to brass side by side, it looks like copper on the cut end. It also appears to be somewhat heavily plated, I think the plating looks thick under a magnifying glass.also, why is the Q of the ferrite one worse then the iron ones. I thought ferrite was supposed to be better Q. But I heard Q is hard to measure so maybe they are doing something different.