Builiding of a complete 6kW PV inverter with MPPT chargers

Author	Message
rogerdw Guru Joined: 22/10/2019 Location: Australia Posts: 881	Posted: 11:59pm 23 Feb 2024         -dex- said   I took a closer look at this large U-shaped transformer and it turned out to be an aluminum winding    I have to find another one. That's a shame. I remember the first time I found a transformer with aluminium wire and I was shocked. Felt ripped off because it's like they purposely colour the enamel to make it look like copper.   Quote   The first winding was covered with varnish and then wrapped twice with thin Kapton tape. I put quite a lot of it because the gaps are quite large, it takes a long time to dry, but I think it is enough to stiffen it. Now I winding the second layer. The target is 223 turns per layer It's looking good and I'm slowly warming to the idea of using varnish on all the windings. I've rarely seen any transformers I've unwound that had any epoxy resin  ...  so I just wound mine as neatly and tightly as possible. I guess it has two advantages  ...  adding to the insulation value  ...  and preventing buzz and hum. I did wonder if it contributed to heat build up  ...  but there are plenty of them out there working perfectly now  ...  so shouldn't be any issue. Besides most of the early SMA toroids were fully encapsulated and they were reliable enough. I think my biggest concern was if I did it wrong and had to unwind it  ...  then I was stuffed. Of course, now that it works I think I probably should have.