Litz wire size for coils

[Darin]

I think I got the wrong wire. I thought I ordered Teflon but ended up being 330/46 nylon and was my mistake I went back and checked so no one to blame but me.
The inductance on this wire is very high, 15 turns on a 8" round 3DSS coil is reading over 1H not mH on my meter.
Anyone else tried nylon litz ? Is this common for this type wire

Back to looking for wire.

[baum7154]

I don't think 15 turns on an 8" 3DSS should be 1 Henry or even 300uh. Can you verify another coil of known inductance to see if the test is having problems? Also make sure the test coil is not near any metal especially a sheet of metal or even a sheet of aluminum foil. Metals in close proximity to the coil will raise inductance significantly. The nylon insulation will only affect increased capacitance versus Teflon.

Regards,

Dan

[Altra]

Nylon or polyurethane is the normal insulation for the individual strands on litz wire. Some is the served with a outer wrap of paper or cotton. Never heard of Teflon litz wire? You need to really heat up the wire to melt the nylon insulation so the solder will bond to the copper. Your high inductance reading sounds like a solder problem.

Add:
Here is some nice litz on ebay that is 25/38awg equivilent to 24awg. He sells by the pound which is a deal


http://www.ebay.com/itm/121651507085...%3AMEBIDX%3AIT

Litz reference guide
http://www.mwswire.com/pdf_files/mws...6_17_18_19.pdf

[Darin]

This is the wire I have.
I tested a 8" 3DSS coil I would a while back with my meter and it reads .294mH I cant remember how many turns it has and the tag I had on it came off and got lost but I think it was around 32 or 33. It was wound with solid copper telephone wire.
I will wind this again when I get home and check everything really good and see what happens.


http://www.ebay.com/itm/160506531193...%3AMEBIDX%3AIT

Thanks for the help guys.

[Darin]

I rewound the 8" 3DSS round mono coil with the 330/46 LITZ from the start to make sure I had everything right. Using my Vici 9808 meter this is what I get.

Resistance 1.642 M ( it will only start ready set at 20M )
Capacitance 4.99nF ( meter set at 20nF )
Inductance .97H (meter set at 2H , will not read set on mH )

I measured a 7" 3DSS round mono coil wound with solid copper telephone wire in the same spot with the same meter. The best I can tell trying to count the turns it looks like 34 turns. I lost the tag that was on it.

Resistance 2.2 ohm ( meter set at 200 ohm )
Capacitance 17.84uF ( meter set at 20uF )
Inductance 2.94 mH ( meter set at 2mH )

Any ideas what I have ?

Thanks again
Darin

[Darin]

baum7154,
is this the type wire you are using to make you 3Dss coils ?

http://www.powerwerx.com/wire-cable/...nded-wire.html

If I remember right you used 26 awg is that correct ?
And would the same size wire to make coils to search for small gold to nuggets be ideal for making coils for surf pro for the beach on coins and jewelry

[baum7154]

baum7154,
is this the type wire you are using to make you 3Dss coils ?

http://www.powerwerx.com/wire-cable/...nded-wire.html

If I remember right you used 26 awg is that correct ?
And would the same size wire to make coils to search for small gold to nuggets be ideal for making coils for surf pro for the beach on coins and jewelry

----------------
I used 24 AWG 19 strand silver plated, 600 volt PTFE aka Teflon insulated wire to make coils that are capable of sampling down to 7us and possibly even lower. This is well in excess of what is required on the beaches. From what I have seen on the forums beach sample delays are more like 12 to 20us. The advantage of 24 AWG is a bit more coil current and when used as a twisted pair feed it is a bit more robust. The wire in the link above is exactly the type I use.

Dan

[green]

I rewound the 8" 3DSS round mono coil with the 330/46 LITZ from the start to make sure I had everything right. Using my Vici 9808 meter this is what I get.

Resistance 1.642 M ( it will only start ready set at 20M )
Capacitance 4.99nF ( meter set at 20nF )
Inductance .97H (meter set at 2H , will not read set on mH )

I measured a 7" 3DSS round mono coil wound with solid copper telephone wire in the same spot with the same meter. The best I can tell trying to count the turns it looks like 34 turns. I lost the tag that was on it.

Resistance 2.2 ohm ( meter set at 200 ohm )
Capacitance 17.84uF ( meter set at 20uF )
Inductance 2.94 mH ( meter set at 2mH )

Any ideas what I have ?

Thanks again
Darin

1.642 M. Bad connection or broken wire.

[baum7154]

I rewound the 8" 3DSS round mono coil with the 330/46 LITZ from the start to make sure I had everything right. Using my Vici 9808 meter this is what I get.

Resistance 1.642 M ( it will only start ready set at 20M )
Capacitance 4.99nF ( meter set at 20nF )
Inductance .97H (meter set at 2H , will not read set on mH )

I measured a 7" 3DSS round mono coil wound with solid copper telephone wire in the same spot with the same meter. The best I can tell trying to count the turns it looks like 34 turns. I lost the tag that was on it.

Resistance 2.2 ohm ( meter set at 200 ohm )
Capacitance 17.84uF ( meter set at 20uF )
Inductance 2.94 mH ( meter set at 2mH )

Any ideas what I have ?

Thanks again
Darin

```````````````````````````
I see that the meter you are using is a VOM with L and C functions too. However it only has a 2mh lowest scale on inductance. Capacitance cannot be measured on a coil as it has to be calculated from SRF and inductance. The 2mh scale is questionable for measuring coil inductances in the typical range of 300 micro henries (uh). It is about 1000 times less resolution for what is needed. Have you had success in measuring search coil inductance with this meter before? If so was it close to the calculated coil inductance for the number of turns?

As a benchmark, an 8" 3DSS round coil with 32 turns should have about 325 to 350uh of inductance if wound with 24 awg wire on a 1 inch wide form with 0.4" deep slots.
Dan

[Darin]

----------------
I used 24 AWG 19 strand silver plated, 600 volt PTFE aka Teflon insulated wire to make coils that are capable of sampling down to 7us and possibly even lower. This is well in excess of what is required on the beaches. From what I have seen on the forums beach sample delays are more like 12 to 20us. The advantage of 24 AWG is a bit more coil current and when used as a twisted pair feed it is a bit more robust. The wire in the link above is exactly the type I use.

Dan

Thanks baum7154,
Then I would be safe making coils for both detectors ( MPP for gold & SM pro for beach ) with this 24 awg like you used ?

[Darin]

```````````````````````````
I see that the meter you are using is a VOM with L and C functions too. However it only has a 2mh lowest scale on inductance. Capacitance cannot be measured on a coil as it has to be calculated from SRF and inductance. The 2mh scale is questionable for measuring coil inductances in the typical range of 300 micro henries (uh). It is about 1000 times less resolution for what is needed. Have you had success in measuring search coil inductance with this meter before? If so was it close to the calculated coil inductance for the number of turns?

As a benchmark, an 8" 3DSS round coil with 32 turns should have about 325 to 350uh of inductance if wound with 24 awg wire on a 1 inch wide form with 0.4" deep slots.
Dan

Maybe I should tell you I just started trying to learn electronics / detectors last year as if it is not abvious. I have only tried a few coils I have made with the telephone wire and it seems that the inductance was under what the coil calculator said ( instead of 300uh my meter set at 2mH would read .250 to 290 depending on the coil ). Most where round bunch coils. I figured it was the wire I used as I know it not the best to use I just had it laying around.
What meter do I need to measure inductance ?

Thanks again for your help

Darin

[Darin]

1.642 M. Bad connection or broken wire.

I wondered the same thing as I tried a continuity test with my meter and get no sound.

[Darin]

I wondered the same thing as I tried a continuity test with my meter and get no sound.

I just tried a continuity test on a 12" piece of this litz wire with no sound at all. I tried to measure resistance on the same 12" wire and it will not give a reading unless the meter is set on 200M.

[green]

I just tried a continuity test on a 12" piece of this litz wire with no sound at all. I tried to measure resistance on the same 12" wire and it will not give a reading unless the meter is set on 200M.

Does the insulation melt back when you solder the strands together?

[baum7154]

Are you sure you are getting the super thin insulation off of each tiny wire using heat and solder adhesion?

Dan