Transformer for bench power supply

[zarquan]

I'm planning to building the bench power supply posted **broken link removed**

The one problem I'm having is finding somewhere to buy a transformer that meets the required specification, 120VA 30V. Although I think the minimum I need is 30V at 2.5A (75VA).

I've looked at Jameco and Mouser for a transformer that meets these specifications, but the only one I can find is a toroidal transformer at Mouser here . This seems rather expensive to me.

Are there any other hobbyist friendly suppliers (will sell in small quantities) that I should look at? Or are transformers like this just inherently expensive.

 

[IanP]

My 2c on this is that you can always connect two smaller transformers (rated for the required current) in such a way that they will give you 30V combined output voltage (primery windings connected to 230V and secondary windings conneted in series) ..

Keep your mind open for other options ..

Rgds,
IanP

 

[Awarapunshee]

Did you try Farnell? they sell in small quantity as well, look at :

https://export.farnell.com/jsp/sear...CQLCIPJK0Q?N=1001645+395579&_requestid=671704

ENJOY!

 

[wizpic]

You can use any type of transfomrer, you can use a 15 - 0 - 15, just join the centre 0&15 together this will give you 30V you need no need to use 30V + 30V

this is the part number I used
88-2538
from here
**broken link removed**

Also you don't have to use Toroidal transfomrer but they are only £12.88 compared to the mouser one it loads cheaper.

Below is my version that I did some time ago

hope this helps

 

[mvs sarma]

You can use any type of transfomrer, you can use a 15 - 0 - 15, just join the centre 0&15 together this will give you 30V you need no need to use 30V + 30V

this is the part number I used
88-2538
from here
**broken link removed**

Also you don't have to use Toroidal transfomrer but they are only £12.88 compared to the mouser one it loads cheaper.

Below is my version that I did some time ago

hope this helps

the output needed is more as it is driven by 2 darlington transistors. If so , how a bridge made by 4 nos of 1N4001 would suffice?

Sarma

 

[wizpic]

sorry that is a typo error they should be 1n5001 which is the 3 amp diodes lets face it not may curcuits draw more than 1amp continuos ?

wizpic

 

[zarquan]

Thanks everyone for the quick replies.

I hadn't looked at either Rapid or Farnell, but I'll take some time to compare prices.

If it is less expensive I might go the route of putting two smaller transformers in parallel (paying attention to phase) to increase the current, but I would prefer if possible using one larger one.

wizpic,
It's great to hear from someone who has successfully built this. I'm wanting to build this party to try my hand at making a PCB so I'll probably use your PCB layout.

 

[wizpic]

I know it did work well it still should be working, I've had it in the loft since I've moved a few years ago so it has just collected dust, I moved on to the Velleman PSU set up 0 - 30V 0 - 10amp and this has never let me down so far I have even charged batteries of it at 5-8 amps continous, But Like I said I don't really set the curent limit to over 1 amp, I must see about getting it down and blowing the cob webs and dust off and use it has another PSU or has a back up. I was aslo wondering some day remove the pots and control it by a PIC (time allowing)