Original poster: Mddeming-at-aol-dot-com In a message dated 12/29/03 8:04:45 PM Eastern Standard Time, tesla-at-pupman-dot-com writes: You know, the primary doesn't *have* to be, ummm, circular...;) Octagonal might be nice. Dan K. Hi Dan, True, but every sharp (small-radius) corner is an opportunity for corona losses. Matt D.