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06-10-2021, 05:12 PM
I used to work in the lighting ballast industry. I wound my own inductors for prototypes & had Heyboer wind & varnish small batches for me once something was finalized. They were 10-15 miles away, and they were kind
enough to give me a tour when I picked up the finished items.
The tour & my inductor design experience got me interested in transformer design, the partial construction of two winding machines, and the hoarding of laminations.
I thought finding bobbins was frustrating...but paper tube was even worse. The insulation companies I reached out to had a US$200 minimum for each type/size of paper tube...so that was a good reason to not complain about bobbins...when I could find the size I wanted.
It is easier to pass hipot/dielectric withstand requirements with polymer bobbins...and (more of a power transformer issue than output), higher temperature ratings that polymers can achieve push paper insulation out of the competition.
I have also disassembled many shorted power transformers...can't prove what failed before what burned, but the books point to insulation system failure (probably localized corona).
I have enough trouble finishing projects, but I know someone who had bobbins 3D printed...I don't know & he didn't care about any 'ratings' for the printed bobbin... he was making an electromagnet for some home project.
Murray
enough to give me a tour when I picked up the finished items.
The tour & my inductor design experience got me interested in transformer design, the partial construction of two winding machines, and the hoarding of laminations.
I thought finding bobbins was frustrating...but paper tube was even worse. The insulation companies I reached out to had a US$200 minimum for each type/size of paper tube...so that was a good reason to not complain about bobbins...when I could find the size I wanted.
It is easier to pass hipot/dielectric withstand requirements with polymer bobbins...and (more of a power transformer issue than output), higher temperature ratings that polymers can achieve push paper insulation out of the competition.
I have also disassembled many shorted power transformers...can't prove what failed before what burned, but the books point to insulation system failure (probably localized corona).
I have enough trouble finishing projects, but I know someone who had bobbins 3D printed...I don't know & he didn't care about any 'ratings' for the printed bobbin... he was making an electromagnet for some home project.
Murray
