Query about torroid temps

[ShinOBIWAN]

Line is 50hz and the traffo is rated for 50/60hz.

I think you only start having problem when using 60hz traffo's on 50hz lines. And not the other way around.

So looks like that is sorted.

Another notes is that I have 2 of these PSU's and 2 transformers, I've just wired the other PSU and transformer up, not the ones I originally mentioned in this thread.

And that work absolutely fine?

No heat no nothing

So what we have here is:

• One PSU and one traffo combo that works fine - no extra heat.
• One traffo that works fine on its own but...
• When connected to the potentially faulty PSU, it starts to cook but...
• The potentially faulty PSU shows no signs of faults and actually works as advertised - a variable bench supply

All this leads me to think that the board is faulty, infact I'm almost sure it is.

[ShinOBIWAN]

Right,

Had the diode tester out and it looks like D2 on the layout below has gone.
Part no. is 1N5819.



The PSU was wired up correctly first time, its a shame I wasted time going through silly theories.

Makes sense now looking at the schematic in the manual, as the 1st winding was shorted hence making the traffo cook.

[richwalters]

Apart from an obvious silly of shorting the centre bolt out on a toroid, any well designed transformer E&I or toroid designed for any particular load shouldn't see a runaway temp rise even 1/2 or 1hr after turn-on for the hand to touch. Toroids temp rise should be kept low as windings are mostly pile-wound. That implies a generous brating.
When the copper losses equal the iron losses then that's the maximum efficiency point.

richj

[ShinOBIWAN]

Originally posted by richwalters
Apart from an obvious silly of shorting the centre bolt out on a toroid, any well designed transformer E&I or toroid designed for any particular load shouldn't see a runaway temp rise even 1/2 or 1hr after turn-on for the hand to touch. Toroids temp rise should be kept low as windings are mostly pile-wound. That implies a generous brating.
When the copper losses equal the iron losses then that's the maximum efficiency point.

richj

Certainly no short turns, it isn't even mounted in an enclosure. But that's not what you were getting at.

Thanks for the more indepth look at temperatures issues with transformers. Again clearly a faulty circuit but I was confused as the circuit actually works rather, blow up or not work at all as most do on a fault and it was this that baffled me and led me to believe my wiring was incorrect.
I even thought the toroid was faulty but that is extremely rare.

[ShinOBIWAN]

PM or Rich could you please comment on my stange goings on in the second page of this thread:

Need help quick please! P101 bias related

Really getting to me as I want to start testing my active XO.

[jacco vermeulen]

Shinobiwan,

if you need some communication with BMM at any time, you can send me an email.
I live a few miles from the BMM shop, no problem stopping by if needed.

J.

[ShinOBIWAN]

Originally posted by jacco vermeulen
Shinobiwan,

if you need some communication with BMM at any time, you can send me an email.
I live a few miles from the BMM shop, no problem stopping by if needed.

J.

Thanks Jacco,

Jean from BMM is a top bloke, really helped me out with some minor probs.

Excellent place to do business and the products are great value for what is essentially commercial grade PCB's.