what is tri inductor

 

We ask people to start new threads when their questions are different from the topic of an existing thread - http://forum.allaboutcircuits.com/showthread.php?t=42026

 

I believe you are thinking of tri-filar.
It is how the inductor is built.

Here is a link to wikipedia's entry on bi-filar. Tri-filar is mentioned at the end of the first paragraph.

http://en.wikipedia.org/wiki/Bifilar_coil

 

You hear the term bifilar coil and trifilar coil bandied about by people trying to sell over-unity equipment (IE, perpetual motion devices). They do this because they sound technical and aren't well understood. Because of the blatant attempts at trying to use this site for promotions of devices meant to cheat people out of their money both perpetual motion and over unity (producing more energy than has been input) have been banned from this site.

Having said that, the device is real and it exists. I'm not sure what it's use is, but Dr. Tesla came up with enough good ideas to take it seriously. I suspect it is used to make a resonant circuit with no real components other than wire, but over time much better ways have been invented to do the same thing, such as crystals.