Can you stack, or daisy chain many transformers for high voltage?

If you can get the right components, even a small Cockcroft-Walton generator can produce very high voltages.

AWOL:
If you can get the right components, even a small Cockcroft-Walton generator can produce very high voltages.

The problem with them is that long ones take forever to charge up and even short ones produce no current at all. Even getting a milliamp of steady output is a challenge.

And yet, there's probably one in that laser printer at the end of your desk.

carl1864:
I'm guessing there is some limiting factor, since I don't ever see small tesla coils making 10 foot sparks.

It's very hard to build a high-voltage transformer. Sparks go right through insulators at high voltages and tend to set things on fire.

Winding an iron transformer for high voltage is pretty much doomed to failure.

The secondary transformer in a Tesla Coil isn't a simple transformer. It works by magnetic resonance, you have to send magnetic impulses into it at the resonant frequency of the coil and get it to oscillate (magnetically). This amplifies the magnetic fields and makes higher and higher voltages in the capacitor at the top as they collapse into it. Optimizing them is a bit of a black art

AWOL:
Cockcroft-Walton generator

I saw that one in London two weeks ago...

AWOL:
And yet, there's probably one in that laser printer at the end of your desk.

True, but that one only has to charge up some dust, not produce big sparks.

You're going to be disappointed if you think you can connect 20 capacitors/diodes in a chain and produce an electricity show to impress girls with.

(I know I was... :wink:

PS: Last year I became the proud owner of one of these: microBrute DRSSTC Tesla Coil Kit - YouTube

There used to be a good mechanical model of the CW in the London Science Museum, using ball-bearings and channels with one-way traps, showing the balls gaining PE as they worked up the columns.

Do they still fire-up the big one? I haven't been there for years.
The last really big CW I saw was in Paris, in the science museum in the Grand Palais.
They did a neat demo of how lightning conductors work, with a model house and some ether.

AWOL:
Do they still fire-up the big one? I haven't been there for years.

Nothing in there looked like it could be "fired up".

It wasn't the science museum I remember as a kid.

fungus:
You're going to be disappointed if you think you can connect 20 capacitors/diodes in a chain and produce an electricity show to impress girls with.

Are girls impressed with this kind of thing? or have I just been chasing the wrong ones? :slight_smile:

Hi, with respect to the diagram showing the possible and not possible configuration of transformers.
The "possible" config should be considered with some very important parameters.

As you add secondaries in series you increase not only output voltage, but voltage difference between primary and secondary windings, and secondary windings and earth.
The transformers may not have been built to these increased voltage stresses.

Tom..... :slight_smile:

A very long time ago, I visited the HT lab at Leeds University.
I can't remember what voltage the primary transformer stepped up ordinary mains to, but the 1MV output secondary stood on a three metre tall stack of ceramic insulators, the base of which stood in an oil bath.

@TomGeorge: Yes, you are right. My answer just covered the basic reason why daisy chaining is imposible, not practical implications of it.
The problem you mention can be overcome by each of the transformers having a second secondary(!) with the same voltage as the primary feeding the next transformer.

@AWOL: I have installed a number of these: http://www.tercosweden.com/wp-content/uploads/2009/07/HV-20110222-lowres.pdf

To really impress the girls you need a Z-Machine:
http://www.sandia.gov/z-machine/

KeithRB:
To really impress the girls you need a Z-Machine:

Drat, to think of all the money I wasted taking them out to movies, dinners and the theater when all I need was one of those. :slight_smile:

I'm sure there's a way to get "Large Hardon Collider" into this thread, but I can't think of it.

You just did. :slight_smile:

fungus, we will assume that that was a typo.

Daisy-chaining transformers just increases the losses, so isn't useful unless you need
the intermediate voltage as well. Good mains transformers are 80% to 98% efficicient (the
highest efficiciencies being for large power-distribution network transformers).

In power distribution there are often several stages of transformer daisy chained because
different parts of the network run at different voltages (2.75MV for national grids, 110kV
for underground cables, 11kV for overhead poles to rural users and city blocks, 240/220/110V for domestic consumers. But if you just want to change voltage at one location a single
transformer is cheapest to make and cheapest to run.

fungus:
PS: Last year I became the proud owner of one of these: microBrute DRSSTC Tesla Coil Kit - YouTube

Even normal ignition coil sparks scare the bejeusus of me, your completely 'nuckin futs' 8)