Why did my TX Burn out Help

pre65 · Post by **pre65** » Tue Feb 28, 2012 8:05 pm

Wiring in parallel will give you 320v @ 400ma.

colin.hepburn · Post by **colin.hepburn** » Tue Feb 28, 2012 8:18 pm

AH right typo error 320v B+ @400mA right that's what I want more current good but do I have the wiring correct in that diagram 320*1.414=424volts no load then or there about

colin.hepburn · Post by **colin.hepburn** » Wed Feb 29, 2012 1:02 pm

colin.hepburn wrote:
Paul Barker wrote:Colin your no current secondary voltage shows two things. That you hadn't bucked the phase, and secondly that the primary is underwound for your mains. this is a problem. I would add a low voltage secondary to the primary, in phase to get the correct secondary voltages, because this will ensure that the core doesn't saturate.

My voltage is 240 aswell, as is most of Britain but I meet people who report 270 volts consistently. that would kill a lot of components.
Hi Paul
Thank for this info i think i will email Ask Jan and see if he will beef up the primary before i order a new one from him
Paul could you confirm if i have the wiring for bridge rectifier use ov to 640v
Hi All
Ok then thanks to Paul
The wiring misunderstanding for 640CT@200mA all windings are connected in series
Same for 540CT @200mAsame but leave the two 50v winding out
Ok good that's two out of the three ways then
Now we want 640@400mA Bridge rectifiers
Right to get this we wire up the winding in parallel correct
See posted image pleas to confirm if I have this right
Thank you

colin.hepburn · Post by **colin.hepburn** » Wed Feb 29, 2012 1:06 pm

Hi All
I would really like a second opinion on

this diagram for the correct parallel wiring for 320v@400ma if its correct or not as i want to order a new TX but not before being sure of the wiring

Mike H · Post by **Mike H** » Wed Feb 29, 2012 1:29 pm

Look alright to me, assuming the windings are drawn in the same phase.

colin.hepburn · Post by **colin.hepburn** » Wed Feb 29, 2012 2:21 pm

Mike H wrote:Look alright to me, assuming the windings are drawn in the same phase.

Thanks Mike
I draw out that diagram from the valve Rec one that I got from Ask Jan the winder of this TX so would assume it's in the same phase as all pin numbers match his diagram

Mike H · Post by **Mike H** » Wed Feb 29, 2012 6:39 pm

Yes I see, as you are going to put them in parallel then to make sure the polarity is correct, you could leave off one wire (red, say, in your drawing) fire it up off the mains then measure across the two tags where you would join those two ends together, should show no Volts as they will be in phase. Or near enough.

Does that make sense?

colin.hepburn · Post by **colin.hepburn** » Wed Feb 29, 2012 6:45 pm

Mike H wrote: Does that make sense?

Yep I think so mike I hate Transformers with more than four secondary wires

colin.hepburn · Post by **colin.hepburn** » Thu Mar 01, 2012 3:12 pm

Just had a reply back from ask Jan
I emailed him to see if I could have a new TRA400TX customized on the primary side for a 10% higher to help with the possibility of core saturation this is not possible with this TX as it an off the shelf job but I could have one made but at much higher cost
He goes on the say
Another problem coming more and more often with LED switch mode
supplies, CFLs etc is DC on the AC line, just a few mV of DC will
saturate the transformer and heat it up, see attached files.

The TRA400 as all our trannies are safe to run in the UK, here
voltage is 230+/-10% as well.

But you may consider including a DC-blocker.

pre65 · Post by **pre65** » Thu Mar 01, 2012 3:16 pm

I'd go for it Colin.

I use something similar to feed my Pre 3 pre amp.

colin.hepburn · Post by **colin.hepburn** » Thu Mar 01, 2012 3:24 pm

Yep simple enough to do I suppose but was just wounding what the general views where on this DC Blocker as I think it was discussed on the old WD site at some point I am sure some had issues with it but can't recall what they were

pre65 · Post by **pre65** » Thu Mar 01, 2012 3:45 pm

colin.hepburn wrote:Yep simple enough to do I suppose but was just wounding what the general views where on this DC Blocker as I this it was discussed on the old WD site at some point I am sure some had issues with it but can't recall what they were

I believe there were discussion about whether the wire up diagram was correct with respect to cap and diode polarities.

colin.hepburn · Post by **colin.hepburn** » Fri Mar 02, 2012 3:23 am

OH dear
I have over looked the way the Germans Spec for winding Transformers
The Current is different to the US spec which is DC after the rectifier

the German current rating is AC so 200mA becomes 120mA this is misleading as he specs the TRA400 in the add as 200mA so even when wired in parallel its only 240mA this is not so good

I would have thought Transformer spec should have be standard with a county's mains voltage the Germany mains voltage is the same as ours so why use AC or is the UK the same

Post by **Nick** » Fri Mar 02, 2012 8:22 am

I may be missing something, but I assumed that the winding rating was a measure of the current the winding will supply. They can't assume what follows, it might be a full wave reg, it might be a voltage doubler and so on.

I normally use the equations on Sowters site

http://www.sowter.co.uk/rectifier-trans ... lation.htm

colin.hepburn · Post by **colin.hepburn** » Fri Mar 02, 2012 12:16 pm

Here's the extract form the email Ask Jan sent me his words not mine I was under the impression each winding was 200mA giving me 400mA in parallel but it appears not
Jan said
The current rating of the transformer (200mA) is for ohmic load ac
given, this is how its done in Germany.

I know that the Amercians rate the transformers as DC after the
rectifier. Which means that 200mA AC result in about 120mA DC rating.

Please take care of this.

audio-talk

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