Am I doing wrong?psu

[intensate]

Help am I doing something wrong here.
I am using a second hand toroidal from a faulyy arcam alpha 3 amp.

I have been using fig 1 ,but only1 half connected and all was ok untill tried to use both bridges.

I tried to run the second bridge and I blew my mains fuse of 1 amp.

I have tried fig 3 as is in Ac and it too blows fuse,is this normal?

I have a feeling that the fault with the amp I took it from was the toroidal.

Thanks all,am I having a scatty day?

 

[Mooly]

You can't connect two bridges like that, and the last diagram has a dead short across the secondary.

Advice 🙂 Wire a mains filament bulb in series with the primary. That will protect the transformer from any mistakes.

If you can measure the AC voltages as marked in fig 2 then the tranny is fine.


What are you trying to end up with voltage wise from this ?

 

[intensate]

Hello Mooly.

I have been using one half of the centre tap to run my jlh amp.
With only one bridge connected I ran it under load at 29vdc and it ran great.

I just thought I could use the other tap to make anothe 29vdc.
I just wanted to make use of the unused tap so it made full use of the transformer and to double it current capacity.

thanks

 

[Ketje]

Help am I doing something wrong here.
Thanks all,am I having a scatty day?

Probably 😀
Mona

 

[Mooly]

The problem is that the centre tap of the tranny means the two supplies can never be separate from each other. If you could break the centre tap connection and bring all four of the secondary wires out separately, then you could do it.

 

[intensate]

I meditated this morning ,got total self belief in my abilitys and modded the transformer.

I spilt the center tap and now I have 2 seperate isolated windings!!!!!!!

Thanks all for your help and advice.

 

[Mooly]

Good stuff