Tesla Coil (Variac) 002

[IAbominator]

Great video but Why do u need money to make you tube videos?

[kubikop]

@IAbominator I cant afford my hobbies so I can not make videos of them...... No one gives anything anyway... ;-)

[Xu53r1X]

ok so does a variac add to the ac current or just amplify/decrease it?

[gushhnet]

actually traic based dimmers won't give you a pure sine wave, so no, it's not the same effect. unless you were to have power factor correction on your device!

[BlenderFreak777]

I used a dimmer switch and the voltage stabilizer blew...idk, must not have had enough resistance or something...of course i had it hooked up to a vacuum cleaner motor lol

[Can101276]

We like to see the through testing, and comparing different (cheaper) alternatives. You are helping to educate us further in the alternative energy field.

Thanks and keep up the professional work!!

[kubikop]

Cheers, I do enjoy making videos if you could not tell.....

;-)

[Drevtoobe]

Hey Paul, an important question: When you turn the dimmer switch do you hear a low-level high-pitched singing coming from the light bulb? If you do the dimmer switch is triac-based, and it it is chopping up the sine wave to vary the power. That is radically different from the variac which outputs a smooth sine wave.

The triac-based output from the dimmer switch is "nasty" and it looks like someone took a meat cleaver to the sine wave.

[Drevtoobe]

The nasty "sharp edges" in the dimmer switch waveform will definitely not be friendly if you want to connect up a small transformer or a coil, etc.

Personally, I can be very sensitive to extraneous noise. I just built a new bedroom computer because I couldn't stand the noisy old PIII. If you set the light level to quite low with the dimmer switch, the screaming whine is like chalk on a blackboard for me. Nor can I tolerate 60 cycle (50!) hum from a TV.

Cheers! lol

[Drevtoobe]

I have never had a 230 volt shock, and the thought scares me! lol I have been shocked by 120 volts a quite few times though.

Pop quiz: How come the electricity in the UK is 230V vs. 120V in North America?

[kubikop]

Is it some think to do with 133Hz that Westinghouse used for efficiency reasons on his transformers?

I know that 240v bites when it touches you its a lesson you only need to learn a few times to always switch of before tampering...

What is it then?

[Drevtoobe]

I think that it's because with 240V wiring you can use thinner gauge wire and still carry the same amount of power as 120V wire. Hence it is cheaper to use 240V wiring. I never looked it up but either I was told it so long ago that I can't remember when or I am just deriving that after thinking about it. No brain atrophy here! lol

Make sure you have a load on the dimmer output when you scope it to see the real waveform.

Cheers.

[kubikop]

You were right its almost a sine wave at full power, but it has negative / positive dips / spikes where the top of the Sine should be... urrrh

Would a big capacitor fix this? Dont know really.

Maybe an AC to DC to true AC is needed then for the dimmer switch....

ps. 110v is more efficient though

[Drevtoobe]

Yes the triac just cuts off the top and bottom of the sine wave. The intended load is a light bulb so it doesn't really matter, if you don't mind the high pitched whine.

There is no real way to fix this, the variac is the real deal. Mind you it hums at 50 Hz. I can't be pleased.

[kubikop]

You can use a diode to change to DC, Then use a circuit to oscillate it. like a pulse motor??

There is always a way we only need to conceive it....

Paul...

[AdminOnDuty]

Actually the Triac will leave the tops and bottoms at full amplitude, but they change when (after zero) the current starts to flow. So typically they lengthen the zero time before turning on. Once on they stay on until the current drops to zero again (which it does 50 times a second in the UK). So just think of them as gated switches that only turn on for one half the cycle and then need re-gated.

Cheers,

[kubikop]

Could we Hook it up to A 400v Electrolytic Capacitor then?

I have 4 Large Ones I got out of a Motor Controller I Have been Saving for some project. They go off the scale on My Capacitance Meter even when In Parallel, or is it series to Quarter it can not remember now?

[AdminOnDuty]

kubikop asked:

> "Could we Hook it up to A 400v Electrolytic Capacitor then?"

If you're asking whether or not the Triac in your dimmer could withstand 400V or not, we would have to look at the model number on the Triac to see. For instance, the T410-400T which is a 4A Triac of the T4 series are rated at Vdrm and Vrrm voltages 600 to 800 depending on the model. The data sheet can be found at the ST website. I'll send you the link . Max amps must be less than 4A so a limiter must be in place

[kubikop]

I meant you could convert to DC using large Capacitors and a rectifier to produce Variable DC Output at High Amperages?

[kubikop]

Ill put it on my scope and tell you...

[Pirate88179]

Great idea with the variac and the dimmer switch. This should be interesting with your coil.

Bill

[kubikop]

Cheers, I think a lot of coilers use them...

Paul.

[BodkinsEnergy]

Nice is that the one from the tesla day?

It was on the table ye!

I had no idea what you do with it!

LOL, Cheers for the dimmer idea.

[kubikop]

Certianly is, it a cheap find....

[rlewis1946]

LOL - I forgot your mains are 240 and your lamp will take that voltage.... For a moment, I was afraid going past 120-125V would quickly burn out your lamp!

Thanks too for the calculations, that really helped me put the experiment and theory together!

Thanks for you videos, always informative.

RL - Atlanta GA, USA

[kubikop]

Glad they helped, I did not think any body word care that much as I was just using a dimmer on a 230v Lamp. But its all adding up to completing my Tesla Coil.....

Thanks.

Paul

[Demoman42]

That Transformer it's pretty cool yo!

[kubikop]

Cheers, managed to pick it up for £20!