Buying certified adapters (i.e. safe, EMC compliant) - and adapter lifespan - Page 1
Forum section: electronics / general

author: tom66
author_rank: Super Contributor
timestamp: October 31, 2012, 07:24:19 pm
content: I'm specing in the power for a product of mine, related to that Wifi question I asked previously. I'm in need of a 5V, 500mA (minimum) power supply.Now there are plenty on ebay... but as we have seen they are not much good at all:The question is, how do you be sure that the "CE" logo on the product is genuine? Unlike some certifications, there's rarely a number you can look up... of course, I can take them apart to see how they're built, but that's quite labour intensive and I'm not 100% on what I need to be looking out for.I have found a few -- looks like the Raspberry Pi ones are good options:http://uk.farnell.com/pro-power/mwusbuk1-black/adaptor-usb-to-uk-black/dp/2100374However, there's no mention of lifespan. I need the product to work continuously at around 500mA for at least 5 years. Cheap electrolytic caps and poor efficiency won't do. The standby power should also, ideally, be low, although I believe the new requirement is less than 1W, so almost any adapter that's worth its salt should meet it.Cost isn't a major deciding factor.

author: Neilm
author_rank: Super Contributor
timestamp: October 31, 2012, 07:50:36 pm
content: Is this for a product that will be placed on sale or for a hobby?If it is for a product then contact the manufacturer and ask for the compliance report. Then you can look it over and decide if it looks OK. It should tell you whether it was done internally in the company or by an independent test house. They should also supply a Declaration of Conformity which is a legal statement saying it meets all the requirements for CE marking.Manufacturers will usually be happy to supply this information if you say you will be using their product as it means that they will sell more. If they don't supply this info, then I would treat the product with a great deal of caution.I doubt if you will find any information on life span, but you could try asking - you never know.Neil

author: mariush
author_rank: Super Contributor
timestamp: October 31, 2012, 08:13:29 pm
content: Contact the power supply companies doing OEM work for others..Fortron (FSP), Delta, CWT, etc....You obviously won't have the buying power to buy batches of 1000+ adapters or more but they may have already designed such adapters and they may be willing to sell you.For example, I see FSP is selling a dual usb adapter:http://www.fspgroupusa.com/adc320tua/p/472.htmlThey may have this with single usb, and they may be able to sell a model cheaper with cable already wired... so you have the certifications already from them.or CWT ... they actually have a large selection of adapters:http://www.cwt.com.tw/Product/enus/Product_ThirdShow.aspx?Series=Adapter&CATEGORY=CAP%20%283W~18W%29Give them an email, see what's the minimum you can buy and all that, maybe they would be even willing to send you some samples.(but I doubt you'd be able to impose your choice of capacitors and all that for a few adapters, maybe if you order 500-1000 and negociate the price and so on)

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 31, 2012, 08:42:56 pm
content: Quote from: tom66 on October 31, 2012, 07:24:19 pmBest bet it to buy from an established distributor, e.g.Stontronics.Not sure you'll find anything with a 5yr warranty in plug-in format, but for internal PSUs, there are plenty of industrial spec units like TDK-Lambda HWS seriesAnother tip for long life is run the PSU way under its rated spec. if you only need 500mA, use a 2A PSU, which will run cooler.

author: PA0PBZ
author_rank: Super Contributor
timestamp: October 31, 2012, 08:45:55 pm
content: The CE marking tells you nothing, it's not that it is tested or something, it's just the manufacturer that declares it complies with certain standards.And then of course you also have this:

author: tom66
author_rank: Super Contributor
timestamp: October 31, 2012, 09:16:23 pm
content: Thanks for the Stontronics link -- lots of useful stuff there and will keep them in mind. Their datasheet for one producf specifies MTBF >50,000 hrs.http://www.stontronics.co.uk/getattachment/8e64343f-2ce7-40a9-b251-336f033c7c7e/6-to-20-Watt-UK-Plugtop-Range.aspxI will probably use the 5V, 2.5A, over the cheaper 5V, 1A, just to achieve better longevity.The product will actually be sold (with any luck) to a large company in the UK on a trial basis (around 20 units for a first run) with any luck they'll be wanting to expand, too. As for its function --.