KitsAndParts.Com Forum

hfs3 · 2010-04-05 14:11:25

OK, got the toroid kit & various sizes of magnet wire. I am attempting to design a power transformer toroid to power the isolated section of a logging voltmeter. I will be experimenting with cores and winding ratios to get the desired result. Since I've never tried this before I am wondering if anyone can tell me about pitfalls, problems, and preferred methods. Of course I will be hand winding, and one question is- how to keep things in place as you wind those many many turns around the very small bobbin. I guess the combo of thumb pressure & tape may help. Is there any type of dope or fingernail polish that won't eat off the coating, but will neatly hold things in place?

I apologize if this is off the topic of RF, but the members of this board are probably well versed in toroids and their construction. Any help will be appreciated.

Thanks,
Harry
(used to be KC4RVK- lapsed)

W4GNS · 2010-04-05 18:13:07

Most comments on the dope/finger nail polish are Don't do it, as if you make a mistake you will have a mess, and I think maybe the dope will affect the toroids also. No, you're not off topic

hfs3 wrote:
OK, got the toroid kit & various sizes of magnet wire. I am attempting to design a power transformer toroid to power the isolated section of a logging voltmeter. I will be experimenting with cores and winding ratios to get the desired result. Since I've never tried this before I am wondering if anyone can tell me about pitfalls, problems, and preferred methods. Of course I will be hand winding, and one question is- how to keep things in place as you wind those many many turns around the very small bobbin. I guess the combo of thumb pressure & tape may help. Is there any type of dope or fingernail polish that won't eat off the coating, but will neatly hold things in place?

I apologize if this is off the topic of RF, but the members of this board are probably well versed in toroids and their construction. Any help will be appreciated.

Thanks,
Harry
(used to be KC4RVK- lapsed)

wa2mze · 2010-04-05 18:41:51

If you HAVE to seal the windings with something, use WAX. Beeswax is the best, or just drip a candle on it.

W4GNS · 2010-04-05 22:30:13

Harry, I'm sure you saw this page, but I'll throw it at you anyway, also Diz has a turns calculator that you can download thats very handy, it also is on this page http://kitsandparts.com/howtowindtoroidswithoutpain.php

hfs3 wrote:
OK, got the toroid kit & various sizes of magnet wire. I am attempting to design a power transformer toroid to power the isolated section of a logging voltmeter. I will be experimenting with cores and winding ratios to get the desired result. Since I've never tried this before I am wondering if anyone can tell me about pitfalls, problems, and preferred methods. Of course I will be hand winding, and one question is- how to keep things in place as you wind those many many turns around the very small bobbin. I guess the combo of thumb pressure & tape may help. Is there any type of dope or fingernail polish that won't eat off the coating, but will neatly hold things in place?

I apologize if this is off the topic of RF, but the members of this board are probably well versed in toroids and their construction. Any help will be appreciated.

Thanks,
Harry
(used to be KC4RVK- lapsed)

hfs3 · 2010-04-06 08:02:50

Thanks to all for the suggestions. I hadn't seen the reference page, it's exactly what I was looking for. I had already taken a blind shot and I found it's not as bad as I anticipated. I guess there are only a few ways to wind wire on a toroid. Actually I find it's oddly soothing, I suppose kind of like knitting, and of course it gets easier as you go, as the unwound part of the wire gets shorter. Also, I found that the stiffness of the wire (AWG 34 in my case) pretty much keeps it in place, so I'll forego any coating, except maybe some tape over the whole thing when it's done. OK, back to winding, 100 turns so far on the primary, about 200 more to go for the rest of the primary & the secondary. Again, thanks for the good advice and 73's to all.
Harry

AD6KA · 2012-06-08 00:32:36

I find that toroids rarely have to be "sealed" or "glued",
if you know how to install them properly and tightly to the PC board.

And if you feel that you absolutely MUST do it
(have microphonics in a VFO due to a loose toroid)..
Do it AFTER you have everything on the PC board installed,
aligned, and working properly.
Then use something permanent like hot glue.
Again, only if you are dead sure everything is %100 FB.

Dave · 2012-10-10 14:10:59

A couple of things I found with toroids is you gotta be careful when measuring with a LC meter, particularly the pic chip variety, they use a low test frequency and the core just might not see it, giving you a false reading, I prefer a dip meter and frequency counter or a receiver.

I sometimes use a dab of bees wax or a minute dab of polystyrene cement on the first and last turn only, preferably on the inside, polystyrene cement looks much better than a clump of melted beeswax, whether right or wrong it never gave me any problems.

Dave

Last edited by Dave (2012-10-10 14:11:42)

wa2mze · 2012-11-21 21:03:47

Dave wrote:
A couple of things I found with toroids is you gotta be careful when measuring with a LC meter, particularly the pic chip variety, they use a low test frequency and the core just might not see it, giving you a false reading, I prefer a dip meter and frequency counter or a receiver.

I sometimes use a dab of bees wax or a minute dab of polystyrene cement on the first and last turn only, preferably on the inside, polystyrene cement looks much better than a clump of melted beeswax, whether right or wrong it never gave me any problems.

Dave

A light spray of clear Krylon should work too.

KitsAndParts.Com Forum

#1 2010-04-05 14:11:25

Newby Question re toroid winding

#2 2010-04-05 18:13:07

Re: Newby Question re toroid winding

hfs3 wrote:

#3 2010-04-05 18:41:51

Re: Newby Question re toroid winding

#4 2010-04-05 22:30:13

Re: Newby Question re toroid winding

hfs3 wrote:

#5 2010-04-06 08:02:50

Re: Newby Question re toroid winding

#6 2012-06-08 00:32:36

Re: Newby Question re toroid winding

#7 2012-10-10 14:10:59

Re: Newby Question re toroid winding

#8 2012-11-21 21:03:47

Re: Newby Question re toroid winding

Dave wrote:

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