Went out of town for a few days & there's 4 new pages.
Someone had checked the resistance on the US NiFe version "Reactor Wire" I've been working & it measured significantly lower then predicted based on specs. I had never noticed this, but then again I never checked resistance on a straight unoxidized wire. It's been bugging the crap out of me ever since as to whether or not the calculated/predicted resistance value for an alloy is based on fully oxidized wire or ?. I strongly suspect it
is based on fully oxidized. I've noticed with all the NiFe builds I've been doing that the Ω always come out almost dead on with Steam engines predictions +-.01-.02Ω max and that's within variations of various device ohm reading accuracy + the various static resistance of the atty's themselves. I need to qualify that statement by saying the accurate Steam Engine predictions are predicated on final Ω reading after oxidizing the coils (bright glow, middle out). I just did some builds before going out of town to check accuracy of wire vs specs & steam engine predictions. First build was US NiFe "Reactor Wire" on a Stillare RDA with nice brass posts. 26ga 2.5mm x 6.5 wrap dual. Per steam engine it should be just a smidge under .13Ω I pre torched the coils as usual to oxidize & then installed.
http://www.steam-engine.org/coil.asp?si=false&a=true&mat=reactor&s=dp&r=0.125&hfnw=40&awg=26&id=2.54
After dry burn & cool down it reads .13 on the DNA-40 (original late style with big screen).
Keep in mind the best ohm meter i have is the DNA-40. So given my limited equipment I decided to do a back to back test of 27ga NiFe Reactor Wire vs the 27ga Genuine Kanthal Nifethal from a sample I have. First I measured each wire with a high quality micrometer with resolution of .00005". Reactor 27 = .01410" & Nifethal 52 = .01405" Super thin advantage goes to Nifethal since thinner should equal more res.
Next I decided to do a single coil build for each alloy designed on steam engine & I would install them one at a time using the same posts on the same atty & same DNA 40
First build is Reactor 27ga I used a 2mm mandrel on coil master, but it does spring a little so measured actual .083" at just over 8.5 wraps (8.71) Steam engine predicts .35Ω
http://www.steam-engine.org/coil.as...r&r=0.35&hfnw=40&awg=27&id=2.1082&ws=0.009906
This is contact coil & first click on DNA-40 reads .23?? (See profile pic) Wow that's way low. much lower then predicted on steam engine & much lower then the discrepancy measured on the straight unoxidized piece I mentioned in the beginning. I haven't been noticing this because my standard practice has been to
torch the coils before installing on the atty. And unlike the straight unoxidized piece this is a contact coil so any shorts across coils will show. A few pulses strums & wiggles later it's firing nice and even middle out, then take it off & give it 5 min. to cool, reinstall & now it reads .36Ω! Considering for this experiment I'm building on a Tobh RDA clone there could easily be .01Ω res in the atty. Either way it's consistent with what I've been seeing in that once oxidized it's almost spot on with Steam engine.
Now for the 27ga Nifethal 52 Steam engine predicts a full extra wrap 9.5 vs 8.5 (all else same) will result in a lower build at .33Ω
http://www.steam-engine.org/coil.as...2&r=0.33&hfnw=40&awg=27&id=2.1082&ws=0.009906
First click on DNA = .27 yikes that's .05 higher then the Reactor, but I know the unoxidized reading is not a trust worthy indicator so lets see. Dry pulse, wiggle, strum bla bla take it off let it cool 5 min like before then reinstall & DNA now reads .32Ω just a snicker under Steam engines prediction.
To sum up my crude experiment:
Reactor 27 = just slightly higher then Steam engine prediction @ .36 with 8.5+ wraps after being oxidized.
Nifethal 27 = slightly lower then predicted on S.E. @ .32 with 9.5+ wraps
Nifethal 27 mics slightly smaller @.01405" vs Reactor 27 at .01410"
The NiFe wires I have been working with must be oxidized to achieve a stable & predicted resistance at least with contact coils.
I will do another experiment with spaced coils, but preliminary suspicion is that spaced unoxidized will also result in lower then predicted resistance until it's been oxidized.
