Quote from: itsu on November 03, 2013, 07:22:48 AM
Concerning the dampening material, i guess the electrical plastic tape is not ideal, so i will change it to paper on the other yoke.

I don't know if paper is less dampening than vinyl.  However glass or mica sheet definitely are.

Quote from: itsu on November 02, 2013, 01:41:46 PM
the other yoke halves ring like a bell (3.842KHz) when tapped.

The cleanest way to determine the fundamental acoustic standing wave frequency of the entire core is to vibrate the ferrite mechanically without the magnetic effects getting in the way of measurement. 
This method also ensures that the vibrations are longitudinal (along the circumference of the core).  See the diagram below:

I would recommend using a piezo disk such as this one, but the problem with it is that you'd need a step-up transformer to connect it to your signal generator, because those piezos like to be powered with a 200V AC signal. 
Maybe a good piezo disk from a Russian battery powered Jack Frost postcard would work right out of the box - Russians like to make their stuff big and sturdy

Quote from: NickZ on November 03, 2013, 08:56:28 AM
  Guys:
   I've spent the last several days trying out different mosfets, resistors, caps, etz...
I've had nothing but problems, for some unknown reasons.  I've blown most every Fet that I have. And the dead Fet pile is growing bigger...
  I don't know if it's because I've placed about 6 more winds of wire on the secondary output coils, or what. But, I've had the Fets blow up like a firecraker, right in my face.  Ha!!!

  So, it's possible that I'm having similar problems like Itsu is seeing, with too much current being drawn, but the light bulbs, even a 25watt one will not light, and the Fets go up in smoke, in two seconds. I've been keeping my finger on them, but they blow, anyway. Just like as if the device were in short circuit.
  Anyways, that's what I've been up to. I hope that some of you are having better luck.

  Geo:  Please re-make your yoke device, and show us some clear close up pictures of the oscillator, so that we can try to replicate it to the T. 
   Were you able to get a meter that reads amps yet?  If not, maybe borrow one?
  Plus, we really need to know if these devices are more than just an inverter, and what news you have concerning the feed back and self charging aspect. Are you getting anywhere with that.
                 Thanks,
                             NickZ

Nick,

Steer away from TO220 devices. The TO247 package mosfet will serve you better for this Royer application. Go for at least 200V devices with a current rating of at least 50A. The other important build point is to keep your gate leads really short, so try mounting the mosfets end to end so that the leads are facing. This will allow you to interconnect with the shortest connections possible. Make sure you fit either 15V or 18V zeners between gate and source leads with a 5W rating. Also, fit fast diodes across drain and source leads. This should at least prevent smoke for operating voltages up to 24V. Rather than using just one capacitor, its better to parallel several smaller value devices to the same value as the one separate cap, as Geo shows in his videos.

Hi all,

Quote from: NickZ on November 03, 2013, 08:56:28 AM
  Guys:
   I've spent the last several days trying out different mosfets, resistors, caps, etz...
I've had nothing but problems, for some unknown reasons.  I've blown most every Fet that I have. And the dead Fet pile is growing bigger...
  I don't know if it's because I've placed about 6 more winds of wire on the secondary output coils, or what. But, I've had the Fets blow up like a firecraker, right in my face.  Ha!!!

  So, it's possible that I'm having similar problems like Itsu is seeing, with too much current being drawn, but the light bulbs, even a 25watt one will not light, and the Fets go up in smoke, in two seconds. I've been keeping my finger on them, but they blow, anyway. Just like as if the device were in short circuit.
  Anyways, that's what I've been up to. I hope that some of you are having better luck.

  Geo:  Please re-make your yoke device, and show us some clear close up pictures of the oscillator, so that we can try to replicate it to the T. 
   Were you able to get a meter that reads amps yet?  If not, maybe borrow one?
  Plus, we really need to know if these devices are more than just an inverter, and what news you have concerning the feed back and self charging aspect. Are you getting anywhere with that.
                 Thanks,
                             NickZ

@Nick

Been busy, with family and friends around, helping them with Flywheel Gens. As a start. oh well will get back to the bench and able to show and more.

Oh yes, I also blown alot of  Fets too, As I said befor this devices is very very Sensitive. As again The Acoustics have odd behaviors even if the splits are far away from eachother, but when it peaks to a higher tone, it can also easily damage your circuit.
Yes I finaly got my amp meter and a and another meter for everything els.
To be honest, I'm not even putting to much time on that the Roundcore , sins busy on the RMG.
But, As I promised I will be rebuilding the original soon with the IRFZ34N mosfets. 1kohm 1/4 watt.

I think it's a bit more then your ordinary inverter, but it's hard to tune. As for the test you guyz did.
but happy to see you guyz working on it too and able to see some measurements.


   @Itsu

Thank you for posting your videos and replication of the Roundcore. Awesome to see that it's functioning as how i have it in some way. My IRFP260N's also get hot over time when using the core, as how one of the Fets  starts to get hot and the other one stays a bit cold, happens to me too. same for the IRFZ34N mosfets I used in the original testing on a 1kW halogen partially lit

Your test with the core you did with the Magnet was interesting , never thought of that but as I see it Influences the fields, you could let it stay in normal mode and then tweak it with the magnet into special I gues hehe, just a thought.

Yes I guess Higher Quality Mosfets should be tried here,  like 500V Fets low RDS or higher Voltages like 900Volts mentioned by Magpwr earlier.


@Verpies:

Yes that pic you posted with the two splitted core with Piezo Disk looks interesting, should be tested.


PS:
I will upload my RMG Schematic soon, it has interesting effects and how the Flyback 2split core is used here.


       Cheerz~

Hi guyz,

check out Igor's new test with Circuit, .
Most of it I resemble to my RMG circuit. awesome

http://www.youtube.com/watch?v=Zp9KgQPlP28

this should help you guyz with Ideas too.


Cheerz~