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Jul 20, 2019 at 2:14 comment added Jacob Pew @RussellMcMahon Ill definitely do it with one of them, I'm also interested in making a convection heater to melt metal with. Not sure what i would use it for yet, but it would be super cool.
Jul 20, 2019 at 0:31 comment added Russell McMahon @Pew_pew_w39 Take one of the spare Es, apply 6V to the mains primary (230 VAC winding in my case) and try it as an electromagnet. Using the original flat end lamination it has more holding power than I can budge. (I'm ~= 80 kg). Using a thick steel mower blade across the E it will support my weight. I haven't "calibrated" it yet. Using thin sheet steel the holding power is far lower. I didn't expect that even though I should have. (My version is going to get used by my High School Science teacher son).
Jul 19, 2019 at 14:41 comment added Jacob Pew @RussellMcMahon some of the larger what I am calling new (~2005 models) come with some nice sized small squirrel cage fans in them that I suspect will produce some nice air flow. In order to get transformers close enough to match without major modifications I have already torn open 10+ microwaves and salvaged all of the parts. I currently have more fans, motors, and microwave circuit boards than I know what to do with, but maybe one day they will be put to use. Today my plan is to make an intimate connection between the 2 and now there looks to be about a .5 mm gap between 1 of the outer legs.
Jul 19, 2019 at 14:15 vote accept Jacob Pew
Jul 19, 2019 at 12:28 comment added Russell McMahon ... You mention wire current rating but that is usually for an acceptable drop over distance. Using somewhat lighter wire for winding and then joining it to suitably thick cables MAY help. A fan also helps. Whether this allows low enough temperature operation is TBD :-)
Jul 19, 2019 at 12:28 comment added Russell McMahon You say "when I weld them together in EE formation. Having the core ends in flat intimate contact and THEN welding them will help minimise any airgap created by the EE arrangement. || MT primaries usually occupy a small part of the winding space (secondary and magnetic shunt takes the rest). You could consider two primaries in series and then add airgap (easily adjustable with plastic or card shims and clamp to hold Es together to get desired magnetisation. Volts per turn will be halved. |...
Jul 19, 2019 at 6:11 answer added Neil_UK timeline score: 0
Jul 19, 2019 at 6:01 comment added Solar Mike @Pew_pew_w39 the reason the wires that are rated for 50 or 60A are ok is because the rating is for an enclosed conduit, bundled with other wires etc and a limited temperature rise. Have the wire in open air and allow it to get appreciably warn and it can pass 100, 150 or possibly 200A without melting the insulation...
Jul 19, 2019 at 2:31 comment added Jacob Pew @KentAltobelli do you think a 555 timer would work for a duty cycle or should I consider trying a different component? I guess I could always use a stop watch, but designing something with integrated circuits sounds better.
Jul 19, 2019 at 2:19 comment added Kent Altobelli @solarmike transformers can't pass DC so it's not a question of the output being "okay with it," instead it's really an issue of the transformer being able to burn that DC safely after saturation. The permeability of the core dcreases rapidly after the knee in the magnetizing force vs flux density plot, so the primary windings will conduct more current since they effectively won't see a giant inductor there anymore
S Jul 19, 2019 at 2:00 history suggested TeilZeitGott CC BY-SA 4.0
corrected spellings, grammar and improved formatting overall
Jul 19, 2019 at 1:57 comment added Jacob Pew @SolarMike I think that was one of the first videos I watched. The problem with all of the videos i have seen is the wire they are re-winding with isn't rated for more than 50-60 A and I would like to have mine closer to 100. Maybe their setup is dividing the current through the transformers, but since the secondaries are in series with each other, they should share the same current. If there is a way to post a picture, I have two cores cut open and sitting like they will be when I weld them together in the EE formation.
Jul 19, 2019 at 1:52 review Suggested edits
S Jul 19, 2019 at 2:00
Jul 19, 2019 at 1:41 comment added Solar Mike @KentAltobelli dc welding is fine, so perhaps that could be an advantage...
Jul 19, 2019 at 1:18 comment added Kent Altobelli If driving from a 555, be very very very precise with the timing so you don't have an effective DC current. This will saturate and overheat your core after running for a little while, you can mitigate this by leaving a small gap when reconnecting your E-E's but at the cost of power output.
Jul 19, 2019 at 1:01 comment added Solar Mike There are youtube videos doing this with mots - can’t be hard... See m.youtube.com/watch?v=tIlaxy9nUVc
Jul 19, 2019 at 0:56 history edited Jacob Pew CC BY-SA 4.0
deleted 223 characters in body
Jul 19, 2019 at 0:49 vote accept Jacob Pew
Jul 19, 2019 at 14:15
Jul 19, 2019 at 0:40 comment added user80875 You should just ask a specific question and nor request "any help." Since there seems to be a fairly specific question in the midst of all of that commentary, I answered that and ignored the rest.
Jul 19, 2019 at 0:35 answer added user80875 timeline score: 0
Jul 19, 2019 at 0:26 history edited Harry Svensson CC BY-SA 4.0
added 5 characters in body
Jul 19, 2019 at 0:24 comment added Hearth MOT stands for Microwave Oven Transformer.
Jul 19, 2019 at 0:12 history edited Harry Svensson CC BY-SA 4.0
The first time you use a very weird abbreviation, spell it out and write in parenthesis. Or do what I did, first time you write it in text, write abbreviation in parenthesis. - This question needs to get tidied up more than I have energy for (some grammar and major formatting)
Jul 19, 2019 at 0:00 review First posts
Jul 19, 2019 at 7:21
Jul 18, 2019 at 23:59 history asked Jacob Pew CC BY-SA 4.0