Torroid Transformer question


Author Message
Godoh
Senior Member

Joined: 26/09/2020
Location: Australia
Posts: 119
Posted: 06:20am 18 Oct 2021      

I bought a dead 8kw Powerjack inverter. It had been butchered by the previous owner when he tried to repair it. So I pulled the Transformers out ( 2 of them) and used them in two new 8010 based inverters.
I noticed that the transformer in one that I use all the time was running hot.
So I had a look and found that there was a steel band around the outside of the torroid, I removed it and also put some small blocks of perspex under the bottom of the transformer to allow better airflow.
This seems to have fixed the heat problem.
My question is does anyone know why powerjack would put an insulated steel band around the transformers in the first place. To me it seems like adding a shorted turn to the transformer and also a way of preventing heat dissipation from the windings.
Maybe it is so that the two transformers would not get tangled up magnetically but I am sure that some of you cluey folk will know.
Pete

Mixtel90

Guru

Joined: 05/10/2019
Location: United Kingdom
Posts: 1526
Posted: 07:38am 18 Oct 2021      

Does this help?

I suspect you are seeing what is labelled as a GOSS band, wrapped round the outside of the windings. The ends are shorted, but it isn't a shorted turn. It reduces stray flux.

Godoh
Senior Member

Joined: 26/09/2020
Location: Australia
Posts: 119
Posted: 08:58pm 18 Oct 2021      

Thanks Mick, I had a bit of a search and read, it seems that shielding is used on things like audio gear to prevent hum etc.
It makes the transformer run a lot cooler without it. So GOSS band begone.
Thanks for the reply
Pete