Power Supply Unit

[kolias]

I want to build a power supply unit and have a hard time to find a toroidal transformer about 25VAC, 200VA

Anyone knows an online store?

[Al_The_Man]

Have you emailed Antek Antek - Your reliable source of transformers, power supplies, and more. he manufactures them and also sells on ebay under Jonango.
Alternatively buy one that is close and take turns off to suit, usually easy with a toroidal.
Al.

[john_100]

Hi Kolias ,

I've just had a look at RS components in the UK RS Components | Electronic and Electrical Components

they list a 200VA 24V transformer number 361-6282

following the link from RS components international www.rs-components.com
to here -

Allied Electronics

this is the nearest I've found

Transformers - Power Products from Allied Electronics

John

ps having had a look at Al's reply go with Antek

[ger21]

Use one of these.
24V CENTER TAP (12-0-12) 10A TRANSFORMER-MPJA, Inc.

[kolias]

[QUOTE=ger21;877698]Use one of these.
24V CENTER TAP (12-0-12) 10A TRANSFORMER-MPJA, Inc.[/QUOTE

Thank you all

Gerry, the one at mpja.com is listed at 10A. What is 10A in VA? I need about 200VA or more

[Al_The_Man]

Roughly equivalent to 240w, (10A at 24v = 10x24 = 240VA).
Al.

[kolias]

Thanks again Al

I’m getting lots of help to build a power supply and along with the help I was given this document to go by:
http://campbelldesigns.net/files/pow...ply-part-1.pdf

This document shows the transformer to have 8 wires and the one suggested by Gerry looks like it has only 3 wires (2 blues and 1 white)

The price and specs looks good but I’m only skeptical about the 3 wires.

Also under outputs it says 24VAC @10A (12V-0V-12V). What the 12V-0V-12V means

[Al_The_Man]

This means it has 2x 12v secondary windings, so in your case, if you ignore the 0v centre tap and connect your bridge rectifier to both the two 12v outer ends you end up with a 24v secondary.
This will give you a DC voltage of 24 x 1.414 = ~34VDC.
Off load, some transformers are slightly higher than rated, but then you also have around 1.5v drop across the bridge rectifier.
Al.