unknown power inductor - Page 1
Forum section: electronics / repair

author: moose
author_rank: Contributor
timestamp: February 07, 2025, 07:18:10 am
content: HiI have 2 night lights that get charged wirelessly. The picture is of the transmiting inductors.The one on the right used to work until i opened the case!The one on the left still works and has the following values: marking A6C; 25mm dia 10mm high; 13ohms; 3.3mH; 18uF.Can anyone identify it so i can try & locate a replacement.thanks

author: WattsThat
author_rank: Frequent Contributor
timestamp: February 07, 2025, 07:51:24 am
content: You will not find that as a replacement part somewhere, it’s custom high volume low cost.Realistically, either fix what you have (which isn't difficult) or chuck it in the bin. Unless you cracked the core, what’s the issue? Just a broken wire? You can fix that…Worst case, you might have to rewind. All that takes is a core (which you have), magnet wire (that you might be able to reuse) and some polyester tape. It’s not brain surgery.

author: benj38
author_rank: Frequent Contributor
timestamp: February 07, 2025, 07:51:58 am
content: This is in all probability a custom wound coil, and not an of-the-shelf part, so finding this exact part is probably not an option.You should try to repair/rewind it yourself. Think of this coil as one half of a very inefficient transformer; as long as you get the number of turns right, or even just in the ballpark, I believe it would work fine.

author: moose
author_rank: Contributor
timestamp: February 07, 2025, 08:13:59 am
content: thanks benj & watts...i snapped about 5 wires when i opened the unit...i'll give it a bash in fixing it, failing which i'll rewire it.

author: Zero999
author_rank: Super Contributor
timestamp: February 07, 2025, 12:22:54 pm
content: I recommend replacing the wire and rewinding it.Unwind the coil onto a spool. Keep any broken parts. Now you can measure the length of the wire.Now, measure the thickness of the wire. If you don't have a micrometer, then wind some of it round a nail, so the turns butt up against each other, forming a single layer. If you wind 10 turns then measure how much room they take, then you can figure out how thick the wire is.Buy some new enameled wire of as closer thickness as possible.Now rewind it as neatly as possible.

author: moose
author_rank: Contributor
timestamp: February 08, 2025, 05:03:50 am
content: as a matter of curiosity...how would one go about actually looking for something similar? how would one even describe it so as to search and see if there is actually anything vaguely similar?eg is it a 'toroidal power inductor'? or a 'power tranmitting inductor' or...or...or...

author: benj38
author_rank: Frequent Contributor
timestamp: February 08, 2025, 08:56:26 am
content: Quote from: moose on February 08, 2025, 05:03:50 amThe term "Wireless Charging Transmitter Coil" is used by some manufacturers of similar things:https://www.vishay.com/en/inductors/wireless-charging/

author: moose
author_rank: Contributor
timestamp: March 09, 2025, 08:56:17 pm
content: To close off this thread....Thanks Benj & Zero for your suggestions.in the end, i unravelled all the wire of the wireless power inductor & added the up the various pieces - 18m of wire (give or take).Purchased 100m of 0.2mm transformer wire from aliexpress.Unwound 18m & made a mark then rewound it.Set up a jig using 2 solder roll holders...for the 100m roll i pushed a sponge against the roll to act as a brake.for the power inductor roll, i pushed a length of 6mm rod thru the central core hole to act as an axle.then i started winding & winding & winding...once i saw the mark, i could put some kapton tape around the inductor to prevent the wire from unravelling, then cut the wire & soldered the 2 ends to the board.Yes...it all works well!Would i do it again....yes, it wasn't that arduous a job.