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Transformer Rewind

spike47

Member
Hi
I am going to rewind a small transformer, the size of the wire it had on was 0.06mm x 9 strands in a bunch, now I can't find that size anywere and if I did I would need 9 bobins of that size, I would lke to know what single strand size wire I could use that would carry the same current !.

cheers
Spike
 
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Pommie

Well-Known Member
Most Helpful Member
To keep the same cross section area, you need to multiply the diameter (0.06) by √6 which is 0.147. However, with 6 strands you will get more skin effect so it'll need to be slightly thicker. Maybe something like 36 SWG(0.193mm).

Mike.
Edit, what is the transformer to be used for?
Edit2, misread your post as 6 strands, for 9 replace √6 with √9. So still ~0.2mm wire or 36SWG.
 
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JimB

Super Moderator
Most Helpful Member
, the size of the wire it had on was 0.06mm x 9 strands in a bunch
When you say "in a bunch", do you mean that the strands were bound together with fine silk or cotton?

Also, for very fine wires in a multi group like nine individual strands, you may be better searching for "Litz Wire", but beware it may be expensive.

JimB
 

spike47

Member
To keep the same cross section area, you need to multiply the diameter (0.06) by √6 which is 0.147. However, with 6 strands you will get more skin effect so it'll need to be slightly thicker. Maybe something like 36 SWG(0.193mm).

Mike.
Edit, what is the transformer to be used for?
Edit2, misread your post as 6 strands, for 9 replace √6 with √9. So still ~0.2mm wire or 36SWG.
Hi
Thanks for your reply, I didn't think it as a case of multiplying all the cross sections, ie 4x2.5mm2 cable is not the same has 1x10mm2 !.
Spike
 

spike47

Member
When you say "in a bunch", do you mean that the strands were bound together with fine silk or cotton?

Also, for very fine wires in a multi group like nine individual strands, you may be better searching for "Litz Wire", but beware it may be expensive.

JimB
Hi
Thanks for your reply, one of the secondary coils on the Transformer has a multi wire wound coil made up from 9x 0.06mm dia wire soldered at the ends, each strand is of course insulated ( laquered) .
cheers
Spike
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Hi
Thanks for your reply, one of the secondary coils on the Transformer has a multi wire wound coil made up from 9x 0.06mm dia wire soldered at the ends, each strand is of course insulated ( laquered) .
cheers
Spike
You're still telling us nothing - what type of transformer is it, and exactly what is it going to be used for.
 

spike47

Member
You're still telling us nothing - what type of transformer is it, and exactly what is it going to be used for.
Hi
Thanks for your reply, it is going to be used has a sort of "Megger" testing at 420v , am not realy wanting to know what the wire will be used for, I just need to know a average load for 9x0.06mm dia soldered together each end and (each strand is insulated and Laquered) , then to convert that to a single strand !.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Hi
Thanks for your reply, it is going to be used has a sort of "Megger" testing at 420v , am not realy wanting to know what the wire will be used for, I just need to know a average load for 9x0.06mm dia soldered together each end and (each strand is insulated and Laquered) , then to convert that to a single strand !.
You're still telling us very little - is it a low frequency transformer, or a high frequency transformer? - if it's high frequency then you probably need Litz wire, as already suggested, which is why it was used originally.
 

spike47

Member
To keep the same cross section area, you need to multiply the diameter (0.06) by √6 which is 0.147. However, with 6 strands you will get more skin effect so it'll need to be slightly thicker. Maybe something like 36 SWG(0.193mm).

Mike.
Edit, what is the transformer to be used for?
Edit2, misread your post as 6 strands, for 9 replace √6 with √9. So still ~0.2mm wire or 36SWG.
A=πr2=
3.14x0.03x0.03=0.0028mm2 x 9 = 0.0252mm2 !

Spike
 

Pommie

Well-Known Member
Most Helpful Member
Multiplying your wire diameter by 3 (=√9) gives 0.09 radius. Pi * 0.09² gives 0.025mm². I admit, 0.2mm diameter is (slightly) more than 0.18mm (twice radius) to allow for a slight (or maybe huge, depending on frequency) skin effect might be excessive but seemed prudent.

Mike.
 
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spike47

Member
TT1418 Rev 27.09.21 edited PS 2.jpg
 

spike47

Member
Primary: – 110 – 240 V

Secondary S3 – 420 V @ 3 mA

Secondary S1 – 6 V @ 32 A

Secondary S2 – 13.2 V @ 400 mA
 
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