From: mystuffs@orwell.net (Metlicka Marc)
Date: Sun, 24 Feb 2002 17:54:07 -0500
Subject: Re: [TSSP] Marc's flat coil
Bart, You are right, the measured wire is .0137", but i bought it as heavy build? Guess i got short changed on that on, ebay! The outside diameter is 20" as measured with lathe calipers. Thank you for pointing this out, i'm sorry for any calculating troubles this may have caused. Take care, Marc "Barton B. Anderson" wrote: > > Hi Marc - > > Neet! Glad to see another flat coil being measured. Can you do me a > favor and check the outer diameter around the coil to ensure it's 20" > consistently around the coil? Also, have you measured the bare and > insulated wire diameter with a dial caliper? I'm finding it difficult > to figure out how to get 756 turns with heavy build (the total > insulated wire diameter should be somewhere around 0.0146". If it's > nearer to 0.0136", then it's single build). With this single build > value, the outer diameter calc's to 20.005" which matches your > measurement. > > Take care, > Bart > > Metlicka Marc wrote: > > > All, > > Flat coil update from Marc M.: > > > > I finished unwinding and rewinding the 20" OD coil, It is flat and > > has > > very little "lifted turns". > > I have so far (last night) checked some parameters and have gotten: > > > > 20" coil wound with 28g heavy build mag wire, all windings are > > tight, > > But in using duct tape as a holding surface, the coil looks kinda > > like a > > "brick wall" due to the tape overlaps. I don't think it will effect > > operation, But it may be note worthy? > > I have counted 756 turns from a 38" ID around a brass bolt, > > outward. > > Sooo: > > 756 turns > > 10" radius > > dc resistance checks at 125.46 ohms > > Inductance measures at 93.06mh @ 1khz > > series Q = 4.3 > > A quick check of selfC measures at 40pf from inside wire outward and > > > > 38pf from outside end inward (measured just for giggles) > > > > All measurements were made with an esi model 250 DE universal > > impedance > > bridge. > > All measurements were made with the coil 38" from the floor, > > positioned > > on an all wood bar stool, 5' clear space on all sides and a ceiling > > height of 7' 8". There are some heavy metal items against the wall > > and > > around the coil starting at 5' away (drill press, hobby lathe, > > "HUGE" > > heat sink on an ac drive leaning against wall) so if needed i will > > clear > > further. > > > > Tonight i will sweep for fo, double check selfC with my general > > radio > > capacitance bridge and do some playing around, also try to get Paula > > to > > count turns for accuracy (after counting the 3k coils turns twice > > for > > me, this may be difficult?), I will post results. > > > > Any further suggestions for testing will be greatly appreciated and > > I > > will promise to give 110% to get accurate results. > > > > Take care, > > Marc M.
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.