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About amps transformer rewinding ?

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Surely it's easy to just record whether it went clockwise or anti-clockwise, and wind the new winding the same way?
 
21:4 would usually be a turns ratio - for every 24 turns on one winding, there are 4 on the other. However, in audio transformers it is likely to be an impedance ratio, and with SMP transformers it might be something I don't know about, though others here will.
 
Theres little point in noticing just which way the winding went, the polarity of the field is dependant on both the direction of the winding and electrical polarity, and seeing as a trans cannot stand much dc even that isnt that important unless the design has a dc element.
 
I was thinking it would be important for phase, if any winding is the opposite way it would be 180° out...
 
The only HF transformers I have ever seen outright fail were in high powered SMPS for welders and plasma cutters and even thein the primary fail issue were only in those that they used cheap aluminum or copper clad aluminum for the windings and it simply got so hot it melted itself down at the connections.

Miller Inverter welders to be exact. I used to work for a local welding supply chain store I ordered the replacement parts for the Miller inverter welders by the case.
 
The only HF transformers I have ever seen outright fail were in high powered SMPS for welders and plasma cutters and even thein the primary fail issue were only in those that they used cheap aluminum or copper clad aluminum for the windings and it simply got so hot it melted itself down at the connections.

Miller Inverter welders to be exact. I used to work for a local welding supply chain store I ordered the replacement parts for the Miller inverter welders by the case.

Hey tcm :)

Long time no see. How the oilfields/fracking stuff going?
We have MAJOR resistance to fracking here in our Karoo area. People are VERY wary.

Regards,
tvtech
 
I'd be surprised to see an ally wound trans in a miller.
Yes I see about the phase of the windings, that doent have anything to do with the original windings though, unless you reuse one or more them.
 
Actually a very interesting and informative site altogether - good photo gallery too :)
 
Hello,

I am just about to attempt this very same 'project' myself in a day or two, hopefully. But my transformer is much larger and made from EI laminations, and the laminations are welded together. The core weighs about 10 pounds too.
Its the high voltage winding i intend to remove and replace with a low voltage winding for a high current low voltage supply source. There's something like 1000 or more turns on that secondary, and i hate to remove them, but it has to be done. I have no use for a 1500 volt transformer anymore :)
The windings look varnished so i'll have to cut them off and push them out the other side. Going to be a little bit of a pain.
 
I'd be surprised to see an ally wound trans in a miller.

Actually Miller has been running primarily aluminum or copper clad aluminum in almost all of their welder power supplies since the mid 70's including the big high power industrial three phase stuff as well. :(

Believe me I have seen enough that have went to scrap only to find out they are not worth the time and effort to tear apart in the end to know. I have several and a buddy of mine who owns a big scrap yard has a few semi loads of them now covering about every model made in the last 40 years. :mad:

Anyone need a pair of Miller 600 amp 15 -50 volt DC constant voltage power supplies? I will give you a heck of a deal!:p

Lincoln welders are no better either. I think the pioneered the copper clad aluminum concept making their welder transformer windings totally worthless for salvage.:(
 
Hey tcm :)

Long time no see. How the oilfields/fracking stuff going?
We have MAJOR resistance to fracking here in our Karoo area. People are VERY wary.

Regards,
tvtech

We cant do it fast enough or find enough people to do it here! We need two more Electronics techs as of now. Starting pay is around $80 - $100k a year.
Our last guy came all the way from Cameroon and is super to work with and I love his French African accent too!:joyful:
 
Mr al, sounds like a microwave trans, if so watch out for loading.
When a trans is off or on low load thre magnetic flux density in the core is at its highest, microwave trans's skimp on the iron, and the trans would be deeply in saturation with no load (causing it to overheat), as they are designed to allways have a load and use the minimum amount of iron/copper.
If you know the turns/volt you can back calculate the flux density in the core, iron can take 1 Tesla.
 
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We cant do it fast enough or find enough people to do it here! We need two more Electronics techs as of now. Starting pay is around $80 - $100k a year.
Our last guy came all the way from Cameroon and is super to work with and I love his French African accent too!:joyful:

Jeepers...

Sounds like you are flying. That's real money. WOW.
My finger is keeping me back....I should of had it fixed when it went faulty..

Regards,
tvtech
 
I would think that by South African standards $80K - $100K American would make cutting that bum finger off not that big of a deal. :p

Heck if I could get a job in South Africa that paid a $1 million American equivalent and I had to do the workload I do now I would probably cut the damn finger off myself with a dull kitchen knife. :woot:
 
Thats more than I make, but I am 10 mins down the road and its not difficult.
I have interviewed for engineers in the past, and came to the conclusion there arent any, at least good ones.
 
I would think that by South African standards $80K - $100K American would make cutting that bum finger off not that big of a deal. :p

Heck if I could get a job in South Africa that paid a $1 million American equivalent and I had to do the workload I do now I would probably cut the damn finger off myself with a dull kitchen knife. :woot:

Thinking along the lines of a sober Pal with a sterilized sharp wood chisel and a hefty hammer. And sterilized bandages and stuff at hand.

Luckily, I am not a bleeder, under normal circumstances. Better than taking a chance at State run hospitals here lately. Horror stories emerging daily about people going in for one problem.....and they cut/operated on the wrong thing.

They could cut my .....well you know....off.... and that would make me a tool less technician. That would be really bad for me :wideyed:

So I am not rushing into anything. Yet. Gotta keep going with the sets in the meantime while my bench partner is recovering from his Colon op today. At a Private Hospital.

The op went well...cut the bad part out. Now we wait for the results. I hope he is going to be OK.

No good two of us being man down at the same time. That would kill the TV repairs here. And probably the business too.

So, in the meantime, I carry the Fort. Sore/dislocated/broken finger or a combination of those.....I still get stuff done :). Albeit slower.

Regards,
tvtech
 
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