Why still use RIFA - Page 1
Forum section: electronics / repair

author: cybermaus
author_rank: Frequent Contributor
timestamp: July 15, 2025, 09:31:10 am
content: So a friend is trader in some equipment, some of which is more electro-mechincal then electronic.One component for example, is a heavy duty electromagnet holding plate using rectified mains. They sometimes fails, pretty much alwasy on the "input protection"I use "quotes", because it is a very rudimentary slow start input protection, consisting of:- one RIFA capacitor over mains (model PME 271 M 47nF X2 275V)- 4x 33 Ohm NTC in series with hot feeding into the rectifierUnusually, it is never the RIFA, always one of the NTC's that breaks.Equally odd is, manufacterer sends out replacements with the same RIFA and 4xNTCMy question however is: Why still use RIFA? Why not some modern generic X2 filmI see they still sell them on Mouser/TME/DigiKey, but always at high prices, I suspect because some certified equipment must be repaired "in spec"Is there any non-obvious (to me) benefid to the RIFA that newer opaque yellow 275V X2 does not have?Of is this brand just working through a big box of RIFA's they bought in the 90s?

author: tszaboo
author_rank: Super Contributor
timestamp: July 15, 2025, 12:59:24 pm
content: Do you think a manufacturer should cease to exist, if they had one bad series two decades ago?

author: GLouie
author_rank: Regular Contributor
timestamp: July 15, 2025, 02:23:38 pm
content: It is my understanding that Rifa is now part of Yageo-Kemet. My guess is that there is a lot of RIFA branded stock left to sell before the labels say Yageo/Kemet.Personally, I go with any other brand of metalized polypropylene X2 instead of paper, but you may be correct that the OEM has NOS of Rifa and that part is certified for them.

author: cybermaus
author_rank: Frequent Contributor
timestamp: July 15, 2025, 02:28:09 pm
content: Quote from: tszaboo on July 15, 2025, 12:59:24 pmI would think thata) they follow two decades of development and move to plastic instead of paper film.b) they would redesign the packaging to get rid of the association, along with some marketing chaff, even if they did not actually improve the formula.

author: wraper
author_rank: Unknown
timestamp: July 15, 2025, 02:35:47 pm
content: Quote from: tszaboo on July 15, 2025, 12:59:24 pmThey produced that junk for decades and still keep making it. IME those produced in early 2010s are still affected and I have no reason to believe current ones are any better. And it's not just single series but a whole paper capacitor lineup.

author: booscrawl
author_rank: Contributor
timestamp: July 15, 2025, 02:57:12 pm
content: Quote from: tszaboo on July 15, 2025, 12:59:24 pmYes. For instance, Ford should have been liquidated over the Pinto disaster.

author: Kleinstein
author_rank: Super Contributor
timestamp: July 15, 2025, 03:24:49 pm
content: Rifa capacitors are not the only one to fail. Other brands also do fail with similar problems and some were even worse (causing fires and not just smoke there were recalls with quite some TV sets for this).

author: cybermaus
author_rank: Frequent Contributor
timestamp: July 15, 2025, 03:43:04 pm
content: Quote from: Kleinstein on July 15, 2025, 03:24:49 pmYou seem to suggest RIFA only smoked?This is a device I personally worked on (1985 Thyristor based VFD)https://www.eevblog.com/forum/chat/some-really-burned-rifa-capacitors-but-not-x-class/?action=dlattach;attach=1292116;imageAnyway point is not if they were bad or just a fluke.Question is, we moved away from paper. Is there any benifid to use paper based RIFA in modern plastic film era.

author: Seekonk
author_rank: Super Contributor
timestamp: July 16, 2025, 08:37:01 pm
content: I wouldn't recommend using X2 capacitors for this application. KEMET had a note jn their X2 data sheet saying not to use these for capacitive dropping supplies. Many think a X2 rated capacitor is some super duty capacitor for line applications. I discussed this with Jim Lewis and he told me that X2 capacitors are designed to be cheap to pass EMI testing and after 6 months nobody cares if they work. It is a cost driven item. What makes them safe across the line also makes them fail. Moisture ingress causing foil corrosion is one factor. Better to use a good foil capacitor. He said there were requests to make a better X2 capacitor which could take current but the market isn't there. Lots of reports of capacitive supplies failing after a couple years with X2. As a line filter most never know that X2 have stopped working.

author: cybermaus
author_rank: Frequent Contributor
timestamp: July 17, 2025, 04:43:11 am
content: I had the vague memory that X2 (Like Y) was supposed to be "special" in the sense that they should never fail closed, always fail open.So probably extra thick film, and therefore never a better capacity wise, as a lower capacity per volume?So what would you use for mains input filter? Because even if X2 is not better then normal film, surely they are also not worse?

author: Gyro
author_rank: Super Contributor
timestamp: July 17, 2025, 10:04:36 am
content: X caps are "special" but not in the way you think. They are special in the following ways:1. They are the only capacitors that areagency approved(UL, CSA etc.) for direct across the mains operation, fitting a not X rated capacitor is not permitted.2. They don't have particularly thick film compared to other capacitors of the same rating. They do have specified peak voltage pulse specs, 4kV for X1 and 2.5kV for X2 but you would probably find that other film caps of the same rating would achieve similar - but are not tested for that.3. I guess thisisthe one that makes them 'special', they have very thin metallization compared to other film caps. X caps WILL break down occasionally under mains spikes. The metallization is so thin though that it will safely evaporate back from the puncture in the film, letting them open again - with some loss of capacitance over time. It is this property that, as Seekonk says, makes them unsuitable for capacititive dropper PSUs (not an across the mains application). A capacitor with thicker metallization won't lose capacitance and is protected by a series fusible resistor and clamp.Y caps on the other hand are designed never to break down, they have withstand voltages of 8kV for Y1 and 5kV for Y2 and are normally ceramic rather than film.P.S. Rifa PME paper caps exist because they have a higher dV/dt rating than other film dielectrics, including Polypropylene, so are better at withstanding very fast spikes.

author: cybermaus
author_rank: Frequent Contributor
timestamp: July 17, 2025, 10:09:57 am
content: Thanks for anwsering the original paper question as well as the interesting spin off question about X2

author: Zenith
author_rank: Frequent Contributor
timestamp: July 17, 2025, 11:58:08 am
content: I'm late to this one.Rifa safety capacitors were a respectable part, with full certification, UL etc, which were used by major manufacturers who didn't cut corners; HP, Tek, and others.They kept using them, so I assume they didn't cause any warranty problems, or problems in the likely front line life of the equipment, which I'd put at 10 to 12 years. They had a distinctive yellow, transparent plastic casing, which cracks with age, (after about 10 years), moisture enters and the capacitor fails, producing unpleasant smoke and sometimes exploding. Those of us with an interest in vintage equipment are very familiar with all this. Other brands don't seem to have these problems to the same extent.I'd imagine that Rifa or whoever owns the brand now, picked up on this and used a different plastic, which didn't have these problems.If I have to replace safety capacitors, I only use Rifa if nothing else is easily available. It may not be rational but I have it in the back of my mind that Rifa capacitors are trouble.

author: wraper
author_rank: Unknown
timestamp: July 17, 2025, 12:16:18 pm
content: Quote from: Zenith on July 17, 2025, 11:58:08 amKemet acquired Rifa in 2007. IME capacitors made in first half of 2010s still have the issue. As I said, I have no reason to believe they were suddenly fixed after being produced with the problem not fixed for 30+ years

author: Zenith
author_rank: Frequent Contributor
timestamp: July 17, 2025, 12:32:38 pm
content: Quote from: cybermaus on July 15, 2025, 09:31:10 amI doubt it's stock they bought in the 90s. Rifa capacitors which have never been used and have been kept in reasonable conditions, still show the cracking problem. It looks like an age related thing rather than caused by temperature cycling. Almost all unused Rifa capacitors I've seen from the 80s and 90s show it.

author: tggzzz
author_rank: Super Contributor
timestamp: July 17, 2025, 12:55:24 pm
content: Quote from: Zenith on July 17, 2025, 11:58:08 amI had to use RIFA in my HP8562B, because nothing else would fit the space available (bottom right). They will last me out,ordepending on your personalityThat SA istightlypacked. The holes in the heatsink on the left are so 150mm long bolts can hold several assemblies on top of that.Alsohttps://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg3046396/#msg3046396

author: factory
author_rank: Super Contributor
timestamp: July 17, 2025, 05:25:02 pm
content: Quote from: tggzzz on July 17, 2025, 12:55:24 pmDid you have to use "RIFA" (aka Kemet, now part of Yageo), or did you mean to say you had to use "RIFA paper"? as they also have plastic based safety caps in their product range (PHE being an example from RIFA and R46 from Kemet).If I can't find a suitable plastic based replacementIfit a ceramic disc type, Vishay & Murata have these, they also do them with longer leads for replacing the RIFA madness with longer leads.David

author: tggzzz
author_rank: Super Contributor
timestamp: July 17, 2025, 07:15:59 pm
content: Quote from: factory on July 17, 2025, 05:25:02 pmI used RIFA PME 271 M 40/110/56/B 100n x2IIRC that is identical to the ones I removed, since the dimensions were the determining factor.

author: Zenith
author_rank: Frequent Contributor
timestamp: July 17, 2025, 08:21:44 pm
content: Quote from: factory on July 17, 2025, 05:25:02 pmReputation is a strange thing, hard to build, easily destroyed and not entirely rational. I heard a story of the CEO of a major US airline who ordered they weren't to use GE engines, because his wife had a GE washing machine which had been a nightmare. His reasoning was that if they couldn't make a washing machine that was any good, they certainly couldn't make a jet engine.I'd really rather not use Rifa capacitors, because of too many unpleasant experiences. If I do use them, well the 80s/90s ones lasted 10 to 15 years without too many problems, and lessons may have been learned etc. I agree with tggzzz. Even if the capacitors haven't improved, by then our interests will most likely have changed.

author: Cyclotron
author_rank: Unknown
timestamp: July 17, 2025, 11:07:37 pm
content: Quote from: tggzzz on July 17, 2025, 12:55:24 pmI just recapped one just like this and used RIFA for the same reason. They lasted 30 years before so I'm probably going to be in the ground if/when they might be a problem again given the amount of use I'll put on it.

author: Haenk
author_rank: Super Contributor
timestamp: July 18, 2025, 09:29:28 am
content: Quote from: Zenith on July 17, 2025, 08:21:44 pmI do not find this too far fetched. It's the company philosophy - if they don't care about small parts, one could assume they don't care about complex parts, made from small parts.

author: Gyro
author_rank: Super Contributor
timestamp: July 18, 2025, 07:49:22 pm
content: The language is certainly rather similar (quote is from the engine controller BGA solder joint Service bulletin)...https://www.eevblog.com/forum/chat/air-india-flight-ai171-boeing-787-dreamliner-crash/msg5980281/#msg5980281

author: tggzzz
author_rank: Super Contributor
timestamp: July 18, 2025, 08:39:16 pm
content: Quote from: Haenk on July 18, 2025, 09:29:28 amYes and no.If a company grows by acquisition, the acquired bits often have very different cultures - and culture is notoriously difficult to change.

author: tszaboo
author_rank: Super Contributor
timestamp: July 21, 2025, 09:48:20 am
content: Quote from: Haenk on July 18, 2025, 09:29:28 amI do. Within a company there are completely different engineering teams who will handle these different markets.For example Bosch makes drills and automotive parts. The two engineering team is not even in the same country.

author: Seekonk
author_rank: Super Contributor
timestamp: July 21, 2025, 12:20:51 pm
content: Been a long time since GE made washing machines.

author: Haenk
author_rank: Super Contributor
timestamp: July 22, 2025, 01:42:16 pm
content: Quote from: tszaboo on July 21, 2025, 09:48:20 amWhile this is really a huge company with dozens of departments, in my experience, all Bosch items come with a certain level of quality, and that level of quality is above average. I have yet to see a "crappy" Bosch branded item.(Of course, newer Bosch "green" power tools are not as good as they used to be - but still a lot better than many other brands.)So it seems some overlord in management has an eye on the brand reputation not tanking and ensuring a certain level of quality.And if a company starts selling top notch parts, while also offering crap - how should the customer know, what quality level to expect? I as a customer would rather purchase from a company which cares about everything sold under that brand.

author: Haenk
author_rank: Super Contributor
timestamp: July 22, 2025, 01:43:34 pm
content: Quote from: Seekonk on July 21, 2025, 12:20:51 pmYou mean like: today?https://www.geappliances.com/ge/washer.htm

author: tszaboo
author_rank: Super Contributor
timestamp: July 22, 2025, 02:08:06 pm
content: Quote from: Haenk on July 22, 2025, 01:42:16 pmWell, you answered it yourself. The Green Bosch tools are consumer, built down to a price and expected to be working/used only for a few hours. The Blue ones are made to last longer, and they are offered as semi-pro tools. I saw semi-pro, because it's target is probably a tradie who uses the tool sometimes, as opposed to a dedicated tool that is going to get used "8 hours a day".

author: Seekonk
author_rank: Super Contributor
timestamp: July 22, 2025, 02:23:52 pm
content: GE hasn't made washing machines since 2016https://www.ge.com/news/press-releases/ge-agrees-sell-appliances-business-haier-54b

author: Cyclotron
author_rank: Unknown
timestamp: July 22, 2025, 02:37:59 pm
content: Quote from: Haenk on July 22, 2025, 01:43:34 pmGE Appliances is actually a Haier company. Haier and GEAerospace have nothing in common as far as I can tell. Well, beside the use of the two letters "GE".Haier is a Chinese appliance conglomerate and General Electric Aerospace is a US aerospace manufacturer.But facts do not get in the way of a good story as the saying goes. The story of an American airline CEO not using GE Engines due to his wife’s washing machine trouble is fun and almost believable. I believe there are problems with the store.We don't know what year the alleged story may have taken place. But, I’m pretty sure the manufacturers of the aircraft make the decisions on which engines are used in their designs. I also doubt that the wife of a CEO for a large airline company is doing their own laundry.

author: cybermaus
author_rank: Frequent Contributor
timestamp: July 22, 2025, 02:57:11 pm
content: Same false name is true for our once great Philips. Philips has dropped even further then GE on the list of names to look up to. Nothing you see with the name Philips is theirs, except I think toothbrushes and MRI machines. (Weird combo).At least we still have ASML.

author: tszaboo
author_rank: Super Contributor
timestamp: July 22, 2025, 04:53:50 pm
content: Quote from: cybermaus on July 22, 2025, 02:57:11 pmTrue. I was in the Phillips museum a few weeks ago, and it's strange to see all these wide variety of products now completely sold off.They have a room showing the original lightbulbs being made from cotton. And how the company made Eidhoven what it is today. And it's all gone.

author: Haenk
author_rank: Super Contributor
timestamp: July 22, 2025, 06:19:41 pm
content: Quote from: tszaboo on July 22, 2025, 04:53:50 pmYes, really awful. They once were one of the technological leaders - in the world.(My uncle worked for them in the medical devices division until the end of the 80s - when he received an offer by Siemens he could not reject. They even had to pay him for a whole year - for not working (as anti-competitive contractual obligation). I guess he already knew Philips was on the way down.

author: factory
author_rank: Super Contributor
timestamp: September 11, 2025, 01:14:43 pm
content: Quote from: tggzzz on July 17, 2025, 07:15:59 pmApparently there are three different versions of "PME 271 M 100nF" with a lead pitch of 15.2mm, 20.3mm or 22.5mm, question is which is used in the HP 8562B SA? The 40/110/56/B seems to be "IEC Climatic Category" according to the data;https://content.kemet.com/datasheets/KEM_F3011_PME271M_X2_275.pdfDavid