Can my step-up/down transformer be repaired?

[martin18]

Hello there, I brought a 5000W step up/down transformer with me for my appliances when I moved back from the US earlier this year. I'm living in an old house, don't think the wiring is up to much, and from the beginning the transformer would trip the circuit board switch, though I could just flip it back on and it would work (sometimes after a few tries at flipping).

The other day, though, there was a loud bang and not only did the circuit trip but the transformer stopped working. It's strange because there is a red power light on the transformer yet there is no power going to the appliances plugged into it. The transformer has a circuit breaker rather than a fuse, and pressing the breaker does nothing.

Wondering what is wrong with it and whether it could potentially be repaired given that it wasn't exactly cheap? Or am I just going to have to bite the bullet and get a new one?

Thanks for any advice you can give!

 

[Pete999]

Hello there, I brought a 5000W step up/down transformer with me for my appliances when I moved back from the US earlier this year. I'm living in an old house, don't think the wiring is up to much, and from the beginning the transformer would trip the circuit board switch, though I could just flip it back on and it would work (sometimes after a few tries at flipping).

The other day, though, there was a loud bang and not only did the circuit trip but the transformer stopped working. It's strange because there is a red power light on the transformer yet there is no power going to the appliances plugged into it. The transformer has a circuit breaker rather than a fuse, and pressing the breaker does nothing.

Wondering what is wrong with it and whether it could potentially be repaired given that it wasn't exactly cheap? Or am I just going to have to bite the bullet and get a new one?

Thanks for any advice you can give!

MAKER AND DETAILS NEEDED or pic sorry for the caps

 

[martin18]

MAKER AND DETAILS NEEDED or pic sorry for the caps

Thanks for asking Pete

https://www.amazon.com/gp/product/B07MP1NVH1/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[DPG]

If it went with a big bang then the chances are the switching transistors inside the unit have gone pop. This would be terminal unless you are experienced at repairing this kind of thing.

 

[pc1966]

As above, a bang normally means very bad news.

That is very small for a "real" 5kVA transformer so it is almost certainly a switching converter and they tend to fail with a bang and I doubt you could get it repaired for anything under half its price as a starting point (even assuming they can get a service manual for it). Working on SMPSU is hazardous, so unless someone is really competent (electrically speaking) and adequately prepared for such high voltage / high energy work it is not something to do.

So really you are looking at a new unit I'm afraid

 

[martin18]

If it went with a big bang then the chances are the switching transistors inside the unit have gone pop. This would be terminal unless you are experienced at repairing this kind of thing.

Thanks DPG, it was a big bang so I imagine that's it. Just out of interest, what would have caused this? Why didn't the circuit breaker protect the transformer?

 

[DPG]

Thanks DPG, it was a big bang so I imagine that's it. Just out of interest, what would have caused this? Why didn't the circuit breaker protect the transformer?

Overload, or just a random occurrence which can happen with these type (switching regulator) of devices. They aren't actually transformers in the conventional sense.

The circuit breaker may not have actually seen an overload if it was a circuit fault.

 

[pc1966]

Unfortunately semiconductors are very small inside, so they have a limited ability to get rid of large amounts of heat quickly. Basically they are faster "fuses" than most fuses are!

You get special very-fast acting fuses to protect semiconductors, but even then you don't always stop damage but you do stop a fire or explosive ending (if very high power system).

Circuit breakers let through a lot more energy than fuses usually do, so they are utterly useless to stop semiconductor damage. But more often than not it is the semiconductor failing due to voltage stress or similar that is the reason so the breaker firing is more to stop a fire, etc.

 

[pc1966]

If you have a spare half hour this might be of a little interest:

 

[martin18]

Unfortunately semiconductors are very small inside, so they have a limited ability to get rid of large amounts of heat quickly. Basically they are faster "fuses" than most fuses are!

You get special very-fast acting fuses to protect semiconductors, but even then you don't always stop damage but you do stop a fire or explosive ending (if very high power system).

Circuit breakers let through a lot more energy than fuses usually do, so they are utterly useless to stop semiconductor damage. But more often than not it is the semiconductor failing due to voltage stress or similar that is the reason so the breaker firing is more to stop a fire, etc.

Thanks so much to you all. Given that I have to buy a new one and I'm not leaving this old house any time soon, how can I protect it against this happening again, do you think? It'll be a 3kVA one this time, I think.