@TimWilliams I have a new MOT and I converted it to a choke but I'm only getting a reading of 0.100 mH after wrapping 10 times (10awg). It has a 2.7mm air gap that I made using an epoxy and some acrylic shims. Is an LCR meter going to give me an accurate reading on such a large inductor?
In L/sqrt(N), L is inductance which I have measured. So what does L/sqrt(N) equate to? Seems like a super easy equation to find N but I'm just not getting where to plug in the desired inductance of, say. 2mH.
@PSTechPaul Please help explain your calculations for max possible induction. You write, "You can get an idea of maximum inductance by winding a single turn and measuring it. That will give you L/sqrt(N), where N is number of turns. Max turns is area of opening / cross sectional area of wire." I have run a single turn in the empty MOT and get 5 uH.
Thanks for sticking with me through my shortcomings. I'm hopeful that it's much closer to the smoother DC goal than I had thought. BTW...the shunts were definitely removed. I'll gather my new components and a scope and have another go at it.
Thanks @PStechPaul . The disassembly info is helpful. I went after the MOT coils with a drill which caused some damage on the laminations. I also went too far cutting the weld to separate the E and required some grinding to smooth the surfaces. I am at a point where I think I'll hit "reset". I'll get another MOT and do a better job building the choke. When I first drew the schematic, I included the GND connections but realized that was not how I installed it.
@PSTechPaul What are magnetic shunts? Please advise. I told Amazon what happened to my scope and they actually refunded my money so I can get another one.
@PSTechPaul I think I misunderstood your install description for the choke. I did not connect anything to the negative side of the capacitor. I connected the 2 canisters (plus to minus) in series and then connected the bridge and heater at the "Top" capacitor on the positive.
@TimWilliams Thanks for that. I realize that my first attempt leaves much to be desired. It has some nice holes that run through but I just didn't have the hardware. I'm about an hour drive to a decent hardware store so I try to give things a run through before honing in on the details.
@Kartman Is there any way to tell if it's saturating? Besides just seeing if a choke with more windings and a higher mH value works better. Not trying to be a wise a&&...part of me would just love to put this project to bed. The other part really wants to see a near DC waveform as a result of all this effort.
@Neil_UK That's me! I guess my choice of a gap-fill (2-sided tape) may be a problem. It felt genius at the time ;) Also, my choice of winding wire seems to have been a bad one.
@PSTechPaul I cut open the welds and separated the E from the I. Then I used two-sided 3M tape as a spacer and a large vise grip clamp to let this set up overnight. The gap looks fine at ~1mm. I bundled everything together with nylon zip ties. They are situated as to not pass through the core area to maximize the volume for wrapping. Then I started with some lighter wire (14 ga) and passed through about 10 times. This gave an inductance of 0.3mH on the LCR meter. I removed the 14 ga and proceeded with the 10 AWG coil. I'll post a picture soon.
Anyone have a way of testing an inductor during the winding? I don't want to clip the wire if it needs more turns but how else can I get a good measurement? Splicing on a high voltage application seems not so great.
Discussion on question by Daniel Van …
Discussion on question by Daniel Van …