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I'm making a mono coil for a minelab detector and need to know if i can solder two lengths of Litz wire together to get the right reading I need to make the coil work?
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If your careful not to short out the coil doing it. I would "loop out" the little bit that you solder together and cover with a little bit of glue. If it was me I would solder the individual wires together and not just all together to make the parallel resistance better/overall resistance lower.Originally posted by delete52 View Post -
Hi What size coil you like to make for your ML in mono,I may be able to help?the number of turns per size is critical as per size,else it wont start up especially on PI ML machines.Comment
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litz wire
Hi thanks for the replies. The coil i would like to make is a 16" mono. I know the coil should be around 0.5 Ohms and around 300uH for it to work. I should have enough wire to make the coil if i can join the two lengths together. Also what is the foam that is used for the filler or what would you suggest to use? Thanks for any help much appreciated.Comment
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Hi, Ideally the individual strands should be joined and insulated individually but you will probably get away with joining the bundles I have done it with tinned wire before and got away with it and the foam ideally is PE foam, polystyrene foam or you can use polyurethane spray in foam from hardware stores, and try for .4 ohms and 300 uh.Originally posted by delete52 View Post
Regards, Ian.Comment
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Hi,I agree with Ians advice.Ive tried with multistrand an it worked but again not ideal if your seeking optimal.How many turns at 16inch are you contemplate using.Ive used from 22t an dewound one turn at a time towards .5ohm,but coils have fired up ok at this size from .7ohm,even to 1.2ohm.but sensitivity takes a hit at higher resistances an size.
Shielding becomes a critical factor also,an your method when completing your coil.Comment
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litz wire
Hi I would like to get the best that i can from the coil so i will individual join the strands. There should be enough wire to get about 30 turns when i join them. I will do what was suggested and try winding the wire and see what the reading are and unwind one turn at a time to get the right readings hopefully. That will be step 1. Thanks to everyone for your help.Comment
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Hi delete52,
It's a long learning curve but eventually you will get there where in Aus. are you I am in S.A. wait until you try DD's that's a challenge.
Regards, Ian.Comment
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litz wire
Hi A mate gave me a 11" minelab dd coil that didn't work so i pulled it apart and one of the wires was broken off. I was surprised to see a resistor on one of the wires so dose that mean that a resistor can be used to get the right ohms reading?
ThanksComment
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Resistor,what is the value of this in Ohms? What are the other specs. you measure for each loop of the DD. also what wire did you find inside,multistrand? an of course the shielding would be the typical graphite paper sheet that minelab uses in their coils.true! Thanks,U got a pic for what you found?Comment
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Gday Rov The Resistor value in Ohms after i unsoldered it was 0.6 Ohms. Also with the resistor out the uH was 500 uh with resistor back in the reading was 300uH. I think the 0.5 Ohms stayed the same resistor in or out i didn't write it down. I didn't measure each loop of wire. The two loops of wire one was litz multistrand the other one was signal strand very thin wire that's the one that broke of. To hard to count how many turns there were. Shielding was like you said graphite paper. Also had a earth wire taped to the graphite paper. I didn't take a photo of it before i fixed it and glued it back together didn't think of it. Hope this makes sense to you. I don't know much about making coil yet still thinking about making one. I do have 14" DD coiltec coil that is a bit noisy I should cut it open and see if it is a easy fix as well if i do i will take a photo of it and put it on here.
Thanks mate.Comment
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You may want to check this link out about Graphite Paper!
Regards,Originally posted by Cyclonite View Post
RobertComment
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Litz Wire
Litz Wire Manufacturer and Information
LITZ-WIRE.com (see Litz Wire Images below):
http://www.litz-wire.com/
I have made a PDF-File of there Technical Information added as Attachment, which can also be found here on there WebSite in HTML-Format:
Litz Wire Technical Information:
http://www.litz-wire.com/technical.html
Interesting however, is a Table that shows the recommended Frequency VS. Wire Gauges. It seemingly looks like they recommend far thinner Wire Strands than you would expect from the depth of Skineffect Penetration for a given Frequency range for a Single Wire Strand.
Skin Effect Calculations:
http://www.sigcon.com/Pubs/news/skineffect.htm
But probably the explanation lies here:
Skin Effect and Cable Impedance:For the stranded and Litz wires we need to take the stranding and the effect of inter-strand contacts or insulation into account.
http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/audio/skineffect/page1.html
Regards,
Robert
Attachment:
Litz Wire Technical Information.pdfComment
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This is what I found on YouTube on MineLabe's Search Coil. Here you can clearly see the Graphite Paper Shielding:Originally posted by delete52 View Post
Inside a MineLab Metal Detector Coil for P.I (2m36s):
http://www.youtube.com/watch?v=BY7WFyCVO_A
Also, one more YouTube Video on "How to Repair Faulty Metal Detector Coils":
How to Repair Faulty Metal Detector Coils (5m42s):
http://www.youtube.com/watch?v=0Owrk...eature=related
Enjoy!
RobertComment
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Yes from some of my old radio days,Litz wire was Square for max surface area coverage in multistrand an cotton covered. very nice to see these pics. Now some of the later day detractors to what litz wires mean physical can see!the range of difference,all under the term Litz wires an know.
Coil winding an development may have taken a bit of a retarded trend to what it once was,with such a narrow focus on just the generic wires we use today an poor use of science an understanding.Wish you all well anyway with your various coil developments.
regards RovComment
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