Thanks again Mac!! These tables are so valuable. One question though..
What exactly am i looking for in an incidental ground? 1 of the legs making contact where they shouldn't? An overlap in my wraps? Thanks again
Short answer: in your case M, and for most of us including me (when I think I have, rather than having observed it)…Not terminating tightly opposed to the legs' exit path at rotation.
The most commonly occurring, not an electrical expert by any means, I'd say:
1. Positive short at termination (leg hanger);
2. Positive
slipping at termination;
3. Positive short on cup assembly wall;
4. Coil short on cup assembly wall;
5. Crossed leg, neg. short (no load, more obvious);
6. End turn overlap, or discontinuity (
hot leg);
7. Turn discontinuity (for m.c.,
hot turns);
8. Various other nightmares we haven't dreamed of; and,
9. Top cap short.
The last being very common if you don't locate the coil as per the techniques suggested since the Metalhed's thread (at the bottom of the slot). We have that covered, thankfully. And largely
hot legs too if the microcoil is correctly oriented and test fired before wicking, you have a pretty good chance of catching this and identifying any other problem (including a
hot leg by checking each out as batt is pulsed) before the tank is used. This includes
overlaps which are manually introduced but really do show up when you do the final test burn, and we should detect them there. Use power more approximating what you intend to use at least briefly. A hot leg or turn should clear by compressing the coil. They don't and perhaps there's contact towards termination.
So what does that leave? Problems with termination. And these are harder to detect. The first though should be checked all the time and that is the leg hanger. It can show anytime and should be suspected any time there is any variation in res. You really need to look at each of these. And if you're not using some type of magnification, you're likely to miss most of them. Particularly the ones down the cup. It can be just a little flash near the grommet at low power even though the rest of the coil glows normal. The little hidden ones like that are often leg hangers. Sometime a slight bend above the termination point that barely grazes the cup wall. Those get you scratching your head wondering why resistance changes.
A variation of the hanger is a pos slightly slipping out of termination. If it tested correctly at set, the pos end turn is now possibly loose turn too, as some of the tension in that leg has been released. This requires lookin' under the hood and test fire if you suspect it. If you keep thinkin' you missed the button, you might have one. Pretty soon flooding. If you pull as you snip 'em they can snap back under the grommet. Too much tension as you twirl 'em and I've had one insert itself into the grommet with intermittent and no termination. Being sure that legs are bound
but secured by the grommet is essential, not forgetting that bulging can affect airflow.
One of the likeliest causes of m.c. discontinuity is coil
skewing and severely handicaps efficiency. And it happens in the set. It can only be corrected by resetting the alignment and tension of the legs at termination. So a pain. But it goes like this. Your coil is fine. You've pushed grommet in part or all and you push in the pin for final termination. Boom, too hard. That's all it takes to pull the pos. out or both and skew the coil. That's why I referred to it as the
trigger pull. These last few steps of making sure the legs are tightly tensioned and exiting
in the direction of exit of rotation from the coil to termination are critical to prevent the incidental contact of cross or side shorting.
We're talking mm here but that's all it takes to be off to have that contact. Why I've been emphasizing tightening the build with forceps as you terminate. Yes, definitely as beck reminded a few posts back, kink that neg leg up to stabilize the coil immediately, first step. Then patiently set in the grommet, at least in part, until you get a feel for what that does to your coil orientation.
There's always a slight twist in the wire resulting from the wind. Sometimes it presents as you set. It may take a slight relocation of the neg, pos or both under the grommet in one direction or another
and re-tentioning to get it to set straight. Here's where a tension wind helps because it's going to try to return at this point to the position in was wound as you make this adjustment, rather than tweak with the flathead, pull, tweak some more, etc., etc.
Often the inclination is to just try to force the skew out with pulse, compression and adjustment of the coil position. I've done it both ways. I don't think the forced set is as durable. I may be wrong on this but I'm going by the impression that they tend to gunk sooner. I labored with that for a while. Why do some coils get consistently uniformly charred? I don't believe that coils wound and installed in a more natural tensioned state with less handling, torching or forcing are as prone vs. the minimal uniform micro-surfaced annealing and cohesion that forms when you pulse. Having to force shape and position to overcome skew, rather than leg alignment and tensioning kind of blows the build.
Finally, the main cause of all of these things is…using a 510 bottom air clearomizer tank, since skewing that silly grommet can ruin your set every time you put that thing on or take it off. And skewing of either the pin, grommet or both is typically what happens. A reason I was concerned that recent substitute grommets and the new Kanger silicone both have more slip with moisture than the original with its rougher composite texture. However, having the coil fairly balanced fighting to retain it's shape and legs tightly tensioned at opposite 180 deg. is going to resist this change. And if there is some skew, the build more likely to tolerate it without too adverse an effect. Slam your 510 on your mod, all bets are off.
Why for me it's a love-hate relationship with the KPT. It has its limitations. But we have an advantage if we pay attention to the geometry of the thing. Like playing pool, you gots to know where to hit the bumpers (and when you don't), when to hit it tight or softly let it down low and there's no
English where the legs are concerned.
Some thoughts M. Any suggestions, improvements, errors detected, etc. will be noted and appreciated.
Good luck.
