http://www.toroid.com
Here you can also get prewound/insulated primaries and wind your own secondary(s) for a particular application
Here you can also get prewound/insulated primaries and wind your own secondary(s) for a particular application
Anyone try to wind there own toroid with Alpha-Core
They have core with pre-winding primary from 46VA (12$) to 2600VA (85$)
They have core with pre-winding primary from 46VA (12$) to 2600VA (85$)
Also,
http://www.victoriamagnetics.com/
They stock 80 VCT toroidals intended for Leach Amp projects (120v Prim.), but offer anything else you need.
..Todd
http://www.victoriamagnetics.com/
They stock 80 VCT toroidals intended for Leach Amp projects (120v Prim.), but offer anything else you need.
..Todd
actually, toroids are pretty forgiving for handwinding technique. the only place you run into trouble for sloppy windings is at higher frequencies, where you have to contend with inter-turn capacitances. you might want to dip your finished transformer in lacquer or rubber tool handle coating to reduce magnetically induced wire "buzz". all you really need to do for calculation is figure out the required turns ratio, and figure out your correct secondary wire size. you can use just about any type of wire you want for the secondary. i prefer teflon insulated when i can afford it, the insulation is thinner than PVC insulation, so you can get higher turn densities (not as high as enameled wire though), and will not cause shorted windings if A> run too hot, or B> the equipment takes a lightning hit (common here in Colorado).
i've hand wound many toroids for many different uses, and they are much easier to wind than EI core transformers (unless you have an EI core that comes apart so you can take the bobbin out). if somebody wants to build a toroid from scratch, i recommend using the toroid from a computer monitor or TV deflection yoke. they're not as compact as a commercial power toroid (they're kind of funnel shaped, instead of flat), but if you get an old dead TV or monitor, they're free...... and yes they CAN be used for 50/60hz, after all most TVs and computer monitors use 50 or 60hz vertical sweep. make sure to cover the core with some type of insulation, such as tape if you use varnished magnet wire. ferrite is a ceramic, and magnet wire enamel scrapes off easily. also isolate your primary and secondary with at least 2000V worth of insulation, if you use something like black tape, the package should tell you what the voltage rating of the tape is per layer (i don't recommend black tape because it dries out and gets brittle eventually, but i am using it as an example).
i've hand wound many toroids for many different uses, and they are much easier to wind than EI core transformers (unless you have an EI core that comes apart so you can take the bobbin out). if somebody wants to build a toroid from scratch, i recommend using the toroid from a computer monitor or TV deflection yoke. they're not as compact as a commercial power toroid (they're kind of funnel shaped, instead of flat), but if you get an old dead TV or monitor, they're free...... and yes they CAN be used for 50/60hz, after all most TVs and computer monitors use 50 or 60hz vertical sweep. make sure to cover the core with some type of insulation, such as tape if you use varnished magnet wire. ferrite is a ceramic, and magnet wire enamel scrapes off easily. also isolate your primary and secondary with at least 2000V worth of insulation, if you use something like black tape, the package should tell you what the voltage rating of the tape is per layer (i don't recommend black tape because it dries out and gets brittle eventually, but i am using it as an example).
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