[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Air cored Tesla coils for high voltage?



Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi,

If you made it like a "continuous" DRSSTC driven by say a small motor H-bridge IC. There is a "chance" you could make it "lighter"... The coupling would probably have to be more optimal (0.6) which could be a problem... An epoxy impregnated air core like the GMHEICSLR would be nice since the epoxy solves a lot of HV clearance issues.

I have a design for a few amp little charged pumped H-Bridge that is very small and light. About the size of a quarter using surface mount ICs and such. I could dig it up... I think it could run at 100kHz++ It would need primary current feedback added and brought to the input... The rail voltage would be pretty low which might be a problem... Best to go for high battery voltage at lower current in that case.

Nice to know this thread is about Tesla coils ;-))

Cheers,

        Terry


At 06:00 AM 7/2/2005, you wrote:


 So my question could you make the transformers to
power a tesla coil be air cored?

Yes. It's possible to make completely air-cored solid state Tesla coils. There is no HV transformer needed- the coil itself is the step-up transformer and it could run directly off 30V DC. The high frequency inverter that drives it can be very small and light too.


However, they may not be the best solution. An air cored transformer needs to be resonant, and that implies higher current flow for the same output. A Q of 6 is usual, and that means the wire is carrying 6 times more current than a non-resonant transformer or C-W multiplier would. So it needs to be thicker, hence heavier, if it's not to burn out.

Ferrite transformers will work well even if non-resonant. So, while ferrites are heavy, I would bet they would save more than their own weight in copper. These are calculations _you_ will have to do if you're interested in getting an autonomous lifter off the ground ;)

But I notice that military and space HV supplies- where weight really counts- are all made with a HF inverter driving a ferrite transformer that drives a C-W multiplier stack.


 Then another question is could you make the toroid on
the tesla coil be lightweight?

You don't always need one. Sometimes the self capacitance of the coil is enough, if not you can add a series string of small ceramic disc caps. If you use a ferrite transformer then you definitely don't need one ;)


Steve Conner