know where to get cheap transformers - Page 1
Forum section: electronics / projects

author: nus
author_rank: Contributor
timestamp: October 12, 2018, 05:27:14 pm
content: Was looking at building a linear power supply. Cant seem find 36v 5a one under $100 aud. Was thinking about just buying a linear power supply and pulling the transformer out of it. Does any one know where i could get one under tge 70 odd this costhttps://m.ebay.com.au/itm/Variable-Adjustable-Power-Supply-Linear-Mode-30V-5A-Fan-cooling-Electronic-Test/152491756214?hash=item2381378ab6:g:7ZoAAOSwCU1Y3bPA

author: xavier60
author_rank: Super Contributor
timestamp: October 12, 2018, 07:14:07 pm
content: I was looking for a transformer recently for a power supply project.element14 have a large range at reasonable prices,https://au.element14.com/c/transformers/toroidal-power-transformers

author: TimNJ
author_rank: Super Contributor
timestamp: October 12, 2018, 10:12:33 pm
content: Well...I was going to suggest Antek. I've used them for a few audio projects.http://www.antekinc.com/as-2236-200va-36v-transformer/But, shipping to Australia is $75. So I guess that kind of defeats the purpose.Could also try an AliExpress special like this one:https://www.aliexpress.com/item/9V-12V-15V-18V-24V-36V-48V-tranformer-Toroidal-transformer-copper-custom-transformer-220V-110V-2/32886176373.html?spm=2114.search0104.3.30.697c13c7ifd9Vp&ws_ab_test=searchweb0_0,searchweb201602_4_10065_10068_10130_318_10547_319_10546_10548_317_5727315_10545_10696_450_10084_10083_10618_452_535_534_533_10307_532_204_5727215_10059_10884_10887_100031_320_10103_448_449,searchweb201603_60,ppcSwitch_0&algo_expid=ef06bd1c-465b-4db5-871c-719f247cff72-4&algo_pvid=ef06bd1c-465b-4db5-871c-719f247cff72&transAbTest=ae803_5&priceBeautifyAB=0

author: chris_leyson
author_rank: Super Contributor
timestamp: October 12, 2018, 10:53:14 pm
content: Old unwanted uninteruptable power supplies, people don't seem to change the batteries when they die they just buy another UPS sometimes because it's cheaper.

author: mrpackethead
author_rank: Super Contributor
timestamp: October 12, 2018, 11:15:59 pm
content: Its almost a relic of the past, transformers.. :-(

author: station240
author_rank: Unknown
timestamp: October 13, 2018, 12:16:04 am
content: If it helps, I've got a 300VA toroidal transformer with following specs, you can have for $50 plus postage.Two independent windings of: 28V (RMS) 5.3APrimary fuse 3A slowblowConsider it New Old Stock, was for a project I did long ago, got almost no use.Comes with the mounting hardware, just need a 7mm bolt/nut to fix it.

author: nctnico
author_rank: Super Contributor
timestamp: October 13, 2018, 12:23:14 am
content: How about using a switching power supply to get to a lower DC voltage and then post regulate with the linear section. A common mode filter with some capacitors will do wonders for the electrical noise from the switching PSU.

author: xavier60
author_rank: Super Contributor
timestamp: October 13, 2018, 07:47:10 am
content: Quote from: nctnico on October 13, 2018, 12:23:14 amThat's what I ended up doing instead of buying a big heavy toroidal transformer for my bench supply project. The SMPS maintains 3v across the post reg MOSFET so even at 20 amps , the dissipation is easily managed.The large amount of exposed high voltage circuitry is a bother.

author: drussell
author_rank: Super Contributor
timestamp: October 13, 2018, 09:42:45 am
content: Standard stacked laminated transformers in that range (175-200 VA) from a good manufacturer like a Triad or Hammond should be available in the $50 range. A torroid for about $10-15 more.Are they reallydoublethe Canadian price down under?Digikey Canada - ~36V transformersI would generally prefer a good, conservatively rated (and essentially overbuilt) unit from a manufacturer like that rather than the cheap Chinesium that is usually in finished products like cheap Chinese power supplies or small UPS intended for only a few minutes run-time unless you de-rate appropriately for your design.