Thane Heins Perepiteia.

[Kator01]

Hey Gyla,

using the secondary of a transformer ( both variac or fixed step-down-transformer )to drive the primary of another transformer is an absolute no-go.
I once was discussing this with a very experienced electronic specialist ( more than 40 years of experience in different electronic branches) because I was doing this and had such a strange behaviour that I asked this person for advice.
Please bear in mind : How can you ever know the behaviour of two coil´s reluctance/inductance in conjunction with each other ?
Looking a the schematic of such a design ( secondary to primary ) you have created a complicated bandfilter with unknown characteristics. No electronic specialist will do this with transformers driven at grid-frequency.
bandfilter-design is a very complicated subject in hf-electronics
As I said : absolute NO-GO !.

This is the reason I built a variable wien-oscillator ( 20 HZ to 20 KHz ) which drives a push-pull output-stage.
The supply-voltage for the output-stage can be varied between 12 and 100 volt. The output-impedance
is just ohmic an can be designed as low as 4-2 Ohms ( driving a speaker for example )

Only then you can be sure about any measurement-values belonging  only ( since there is no inductive backlash at the low-impedance emitter-output ) caused by the test-object ( bitoroid transformer in this case ).

The other possibility is to drive the primary directly from the grid and measure the amps/voltage and phase-angle
with a scope.
I even do not trust those powermeters you can by. I had used such a device by a professional electronic-company here in germany and it had an 15 % error in amps, so it made me believe I had OU.
I measure the dc-output of a switched power-supply at a linear-ohmic load and was scratching my head because of the measure output-to input-ratio ( 120 % ).
Then I used an analogue-meter for the current-reading which made it clear where the error was.

Bet Regards

Kator01

[gyulasun]

Hey Gyla,

using the secondary of a transformer ( both variac or fixed step-down-transformer )to drive the primary of another transformer is an absolute no-go.
I once was discussing this with a very experienced electronic specialist ( more than 40 years of experience in different electronic branches) because I was doing this and had such a strange behaviour that I asked this person for advice.
Please bear in mind : How can you ever know the behaviour of two coil´s reluctance/inductance in conjunction with each other ?
...

Hi Kator01,

Thanks for the explanations I can accept them, the setup (mains --> variac --> down transformer --> bitoroid primary)  may cause problems but then the situation Thane may have used (mains --> variac --> bitoroid primary) can also be problematic in itself, at least according to your description above.

I based my advice on my practice of using a variac from the mains when findings faults in older CRT television receivers that was installed inside with a 1:1 isolating mains transformers to make it truly ground independent from the mains ground in a television studio. And I never ever found any problem when controlling the variac and feeding the isolation mains transformer's primary input with the variac turned down even to 50-60V AC temporarily, this lower AC voltage always nicely appeared at the isolation taransformer's secondary and then feed the switched mode power supply mains input in the television set.
This is why I though of giving a simple solution for changing the AC input voltage to the bitoroid primary input. 
I do think if variac is used in itself only for getting the low voltage AC of 2-3 Volts to drive the bitoroid's primary, then it is a situation I would avoid by all means for reasons I explained in my previous mail. 

Best Regards,
Gyula

[Kator01]

Hi Gyula,

yes I agree, if you have just an application to test output-voltage in this 1:1 transformer-setup you described. But if it comes to power-factor, phase-angles between current and voltage then it is a no-go.

can accept them, the setup (mains --> variac --> down transformer --> bitoroid primary)  may cause problems but then the situation Thane may have used (mains --> variac --> bitoroid primary) can also be problematic in itself, at least according to your description above.

Yes, that its what I mean. But I simply do not know the supply-source-type thane was using in this demo.

So we have to wait until thane or gotoluc come forward with an explanation, especially if this big toroid is a standard-transformer and how he attached the primary-core to the main-core.

Best Regards

Kator01

[CRANKYpants]

FYI LADIES AND GENTS,

I POSTED THE TOROID VIDEO IN REFERENCE TO A TOPIC OF CONVERSATION EARLIER ON IN THIS THREAD. UNFORTUNATELY I DON'T HAVE TIME TO GET INVOLVED IN AN INDEPTH DISCUSSION DUE TO A PROTOTYPE WHICH I AM TRYING TO GET FINISHED AND THE FACT THAT I DON'T HAVE A COMPUTER RIGHT NOW.

I HOPE THE VIDEO WILL INSPIRE OTHERS WHO ARE CONSIDERING BUILDING A BI-TOROID - THERE IS LOTS TO LEARN AND EXPERIMENT.

THAT TOROID HAS 5 X 1000 TURNS/SIDE AND THE ONLY DOWNSIDE WAS THE PRIMARY TO SECONDARY COUPLING WHICH CAUSED IT TO BE INEFFICIENT BUT STILL FUN. THANKS TO GOTOLUC FOR HELPING. 

CHEERS
Thane

[LarryC]

Hi Thane,

"IT IS SOMETHING I CONTRIBUTED TO - BUT THE TIMING IS OUT OF MY HANDS - I HAVE BEEN TOLD THAT DECEMBER 10 IS THE BIG DAY - SO WE HAVE TO WAIT AND SEE?"

My latest Popular Science has an article about a machine that they state 'MIGHT SAVE THE WORLD'. It is a home brewed fusion proof-of-concept device in Burnaby, British Columbia by Michel Laberge a French Canadian.

Is this the 'Big Day' device?

Regards. Larry