OUR Iron wire Tesla coil initiative.

[Itsu]

Thanks Itsu.

A misplaced Decimal point makes a huge difference....

The Lathe does not have a 1 Metre long lead screw so I shall have to think about down sizing. My other problem is that I don't have a FG that goes into the MHz range. Is there a way of manipulating the coil into the KHz range?

Cheers Graham.

Graham,

with this 1mm pitch and the 160m length of wire, we can not increase the inductance (thus lowering the resonance frequency) to get below 1MHz.
Not even if we decrease the pitch to the 0.71mm diameter of the wire used.

So what's left is to add (increase) the parallel capacitance, like by adding a top load.

Using the above linked Java calculator shows that adding a 10cm diameter sphere as top load will decrease the resonance frequency to below 1MHz, like 987kHz.

But it could be that using iron wire will already show a decreased resonance frequency without any added capacitance.

Itsu

[partzman]

Graham,

with this 1mm pitch and the 160m length of wire, we can not increase the inductance (thus lowering the resonance frequency) to get below 1MHz.
Not even if we decrease the pitch to the 0.71mm diameter of the wire used.

So what's left is to add (increase) the parallel capacitance, like by adding a top load.

Using the above linked Java calculator shows that adding a 10cm diameter sphere as top load will decrease the resonance frequency to below 1MHz, like 987kHz.

But it could be that using iron wire will already show a decreased resonance frequency without any added capacitance.

Itsu

Well, if permissible, you could add a ground plane inside the rigid pvc consisting of a slit conductive tube that fits tightly inside diameter of the pipe.  Rigid pvc has a dielectric constant of 3-4 so this added capacitance could drop the resonance frequency to a more desirable level.

Pm

[Verpies]

Rigid pvc has a dielectric constant of 3-4 so this added capacitance could drop the resonance frequency to a more desirable level.

What about the dielectric loss and its effect on Q ?

[partzman]

What about the dielectric loss and its effect on Q ?

Are you sure about dielectric loss?  My present work involves the investigation of the so-called displacement current in a dielectric.  I am not finished at this point so will not say what I have discovered at this time, but I would recommend that one takes a close look at a simple parallel resonant network during the first cycle start-up!  What is the source of the capacitor 'displacement' current in this observation?
Pm

[Itsu]

Graham,

We could settle for a 100cm long tube with a 1mm pitch, we will and up with 1000 turns, each of 15.4cm length for a total of 154m.

The inductance (copper) will cause the resonance frequency probably to be higher than 1MHz (unknown for iron), so i could do the measurements.

I can order this 0.71mm diameter iron enameled wire together with a similar diameter copper wire from your supplier (Wires.co.uk).

Itsu

[Grumage]

Graham,

We could settle for a 100cm long tube with a 1mm pitch, we will and up with 1000 turns, each of 15.4cm length for a total of 154m.

The inductance (copper) will cause the resonance frequency probably to be higher than 1MHz (unknown for iron), so i could do the measurements.

I can order this 0.71mm diameter iron enameled wire together with a similar diameter copper wire from your supplier (Wires.co.uk).

Itsu

Hi Itsu.

As stated previously my ' screw cutting ' lathe is not long enough, in the bed to accommodate a 1 Metre tube. I could definitely make a 500 mm long one though. However....

I wonder if before committing to a build we should try a  ' quick and dirty ' simple test? Wind say between 10 & 20 turns of both Copper & Iron wire and do an inductance test first?

Cheers Graham.

[Itsu]

Graham,

OK, i understood that you could manage a 1m tube, but not more.

Agreed, i will order some of that wire and make some inductance measurements.

Itsu