transformer sourcing - Page 1
Forum section: electronics / projects

author: RUWO1
author_rank: Newbie
timestamp: August 10, 2020, 10:10:30 am
content: Hi,I was wondering where you all source your transformers for power supplies. I haven't had any luck with the usual suspects like mouser, digikey, etc nor with local electronics shops. EE's have told me to go try making my own but i need about a dozen 240v(mains) to 12V transformers which I would have thought to be fairly common. Where do you buy your transformers?thanks

author: janoc
author_rank: Super Contributor
timestamp: August 10, 2020, 10:22:52 am
content: E.g. Mouser?https://www.mouser.fr/Power/Transformers/Power-Transformers/_/N-8u9n5?P=1y8s5syZ1y8s5srZ1yzuxsfZ1ydkztuZ1z0wcy4Or Digikey?https://www.digikey.com/products/en/transformers/power-transformers/164?k=transformer&k=&pkeyword=transformer&sv=0&pv1393=147953&pv1393=147961&pv1393=150722&pv1393=153583&pv1617=87718&sf=0&FV=-8%7C164&quantity=&ColumnSort=0&page=1&stock=1&nstock=1&pageSize=25All "the usual suspects" stock these things.Of course, you didn't say any other specs, so these may or may not be suitable (power rating, construction, etc.)Maybe you have been searching for the wrong terms?

author: RUWO1
author_rank: Newbie
timestamp: August 10, 2020, 10:36:48 am
content: your digikey link has 4 search results and none of them are really suitable for power supply applications(the output current is in the milliamps range). Mouser has only 2 and i'd like to have just a little more options. I had found these but their stock seems more focussed on other uses, not really power transformers. output current in the 4-6 amp range would be nice.

author: 2N3055
author_rank: Super Contributor
timestamp: August 10, 2020, 10:43:10 am
content: Look at the TME...

author: janoc
author_rank: Super Contributor
timestamp: August 10, 2020, 11:05:48 am
content: Quote from: RUWO1 on August 10, 2020, 10:36:48 amYou didn't say any of that in your original post, only that you can't find any - which is obviously not the case. Those are all power supply trafos but obviously some are for low power applications. Also, a 6A transformer/linear supply is going to be large, expensive and heavy. Unless you have specific reasons for such supply, a switching supply is likely to be a better solution.TME mentioned by 2N3055 has quite a choice (sorry for the horrendous URL - they encode the filters in the URL):https://www.tme.eu/fr/katalog/transformateurs-toroidaux_100028/?s_field=1000011&s_order=desc&search=transformateur&visible_params=2%2C444%2C101%2C445%2C449%2C74%2C117%2C142%2C328%2C456%2C82%2C178%2C436%2C457%2C351%2C450%2C482%2C536%2C317%2C511%2C632%2C1776%2C21%2C397%2C424%2C522%2C2846%2C1467%2C160%2C236%2C1729%2C1605%2C483%2C484%2C487%2C486&mapped_params=445%3A1445082%3B449%3A1445107%2C1811325%2C1445107%3B456%3A1445424%2C1445424%2C1594406%2C1445438%2C1445396%2C1489573%2C1489573%2C1594711%2C1445567%2C1513151%2C1446079%2C1445478%2C1489570%2C1594864%2C1489570%2C1445420%2C1445420%2C1594435%2C1489602%2C1594744%2C1489602%2C1445823%2C1445433%2C1445395%2C1489580%2C1594416%2C1489580%2C1446085%2C1445490%2C1489662%2C1489662%2C1594861%2C1445419%2C1445419%2C1697449%2C1446083%2C1445976%2C1489594%2C1445488%2C1489620%2C1489607%2C1445987%2C1445529%2C1489672%2C1446011%2C1445621%2C1489676%2C1445628%2C1489680%2C1445998%2C1446181%2C1446021%2C1489682%2C1446033%2C1489688%2C1446185%2C1489690%2C1446199%2C1489692%3BIf you don't like toroidal:https://www.tme.eu/fr/katalog/transformateurs-avec-fixation_100531/?s_field=1000011&s_order=desc&search=transformateur&visible_params=2%2C444%2C445%2C101%2C449%2C117%2C10%2C74%2C82%2C436%2C457%2C178%2C456%2C317%2C1729%2C236%2C1362%2C1730%2C450%2C1776%2C482%2C177%2C511%2C453%2C397%2C2356%2C160%2C142%2C484%2C483%2C32%2C1246%2C487%2C486&mapped_params=445%3A1445082%3B449%3A1811325%2C1811325%2C1445107%3BIf you don't like TME, then RS/RadioSpares stocks them too:https://fr.rs-online.com/web/c/alimentations-et-transformateurs/transformateurs/transformateurs-toriques/https://fr.rs-online.com/web/c/alimentations-et-transformateurs/transformateurs/transformateurs-a-montage-chassis/And you can always go directly to the manufacturers and order from them.There is plenty of choice.

author: RUWO1
author_rank: Newbie
timestamp: August 10, 2020, 01:31:47 pm
content: thank you. The reason for the transformers is that we have existing switching power supplies that output variable voltages, but they take 12VAC as a supply.

author: janoc
author_rank: Super Contributor
timestamp: August 10, 2020, 02:06:17 pm
content: Quote from: RUWO1 on August 10, 2020, 01:31:47 pmThen just buy a ready-to-go switching 12V power supply. It will be cheaper, smaller, much less heavy and running cooler than a big trafo + requisite rectifiers and filters. There is a reason why you don't see that many 12V/4-6A mains transformers stocked - nobody is using these things anymore (except some audio or applications where switching noise could be a problem), everything has a switching mains supply these days.

author: themadhippy
author_rank: Super Contributor
timestamp: August 10, 2020, 02:19:43 pm
content: QuoteSo around 50-100VA, plenty of em, everywhere.Even your local electrical wholesaler will most probably will have something on the shelf aimed at the low voltage lighting market.

author: bdunham7
author_rank: Super Contributor
timestamp: August 10, 2020, 02:22:48 pm
content: https://www.mcmaster.com/step-down-transformers/output-voltage~12v-ac/https://www.alibaba.com/product-detail/110v-120v-110v-ac-220v-230v_62024021647.html?spm=a2700.7724857.normalList.68.2c2d2c38nEGA3Q

author: janoc
author_rank: Super Contributor
timestamp: August 10, 2020, 03:46:24 pm
content: Quote from: bdunham7 on August 10, 2020, 02:22:48 pmUh, buying a mains transformer from a random vendor on Alibaba ... I hope you and/or your clients have a good fire insurance, when you are handing out such advice. Especially with specs like:"Coil Structure: TOROIDAL" (picture shows regular EI trafo)"Coil Number: AUTOTRANSFORMER" (picture is regular trafo with insulated windings, but if this is true, then totally unsuitable for OPs applications because lacks galvanic isolation)"Polarity: Subtractive polarity" (what does this even mean??)Oh and the trafo costs $10/piece. Really confidence-inspiring ...The McMaster-Carr link is better but given that the OP is in Belgium, I doubt that they will want to order from there.

author: 2N3055
author_rank: Super Contributor
timestamp: August 10, 2020, 04:07:13 pm
content: That's why I recommended TME..Prices are very good and transformers are good quality. Shipping in EU is very inexpensive and fast..

author: bdunham7
author_rank: Super Contributor
timestamp: August 10, 2020, 04:08:45 pm
content: Quote from: janoc on August 10, 2020, 03:46:24 pmI'm not doing the OP's shopping--not that I could given the vagueness of his requirements--just pointing out that these xformers are still widely available.

author: JohanH
author_rank: Frequent Contributor
timestamp: August 12, 2020, 08:20:15 pm
content: Rather than Alibaba, there are many transformer manufacturers in Europe. Of course they could be more expensive, but I prefer to spend at least some money locally. You can always buy those other small components from China.I've bought a couple of transformers from PowerUC Electronics (Poland), their Ebay user name is powerucpl. They are fine. Even when the stock was empty, they manufactured and sent them in maybe two weeks. Cost was reasonable and I would say competitive.In the past I've bought a transformer fromhttp://www.die-wuestens.de/eindex.htm?/t1.htm. It was a custom ordered big mains transformer, potted toroid. Ordering a custom transformer is more expensive, of course.There is alsohttps://www.toroidal-transformer.com/index.html, a Dutch manufacturer.I'm sure there are many more.

author: richlooker
author_rank: Regular Contributor
timestamp: August 14, 2020, 11:31:21 am
content: Elfa Distrelec stock lots of high quality transformers, eg. toroidals from Noratel:https://www.distrelec.be/nl/voeding/transformatoren/c/cat-L2D_379651Cheers, Richard