I just received two torroidal power transformer kits... yes KITS, from Torroid Corp of Maryland. They give you a pre-wound primary, and instructions for putting your own secondary(ies) winding(s) onto the core. No wire supplied for the secondary since that's load dependent. Instructions are very complete, and there's tables to help you ensure that your secondary will actually fit. Mylar tape to insulate the finished winding(S) also included.There are multiple core sizes available; you pick that when you order. Price for an 80VA core was $30.There is a 250v RMS voltage limitation between any two windings.
I have used the kits from both Plitron and TCM and they are both very good, BUT they are still relatively expensive and if you want a B+ winding there are a LOTof turns to put on. It is much cheaper to tear the secondary off an existingtoroid and wind a new one on although it can require a little cut and try workto figure out how many winds are on the primary.
Each kit contains:Transformer Kits Datasheet * A toroidal core of grain oriented steel * Mylar taped for insulation of secondary windings put on by the customer * Built-in thermal fuse rated at 130C * Manual with step-by-step instructions on how to design and wind the secondary windings. * Metal washer and 2 rubber pads for mounting the transformer * Guide to calculate proper wire size and length required to generate your calculated output data.
As much as I love DIY, and as much as I love transformers, I still would not buy that kit.Why?For one, it's always a little spooky when you mess with the mainsTwo, power transformers are cheapThree, you can wind a good transformer with that kit, but it will not be dipped in epoxy.You need to pull a vacuum on a transformer to get rid of moisture that will corrode wire and insulation, then you need to do a modern varnish impreg, then you need to bake it.Also, you want the power trans to have a company attached to it so you can sue them when your UL Listed xfmr burns up and takes down your apt complex.Do you have renters insurance?For just pennies more, Geico Direct can set you up....