so far a flightless bird

[kennygee]

I really want to get off the ground with the SSG. I need help with my skate size model: Do they really work with a MPS8099 transistor? I am not getting enough current through the main coil to keep the system running. My coil is 1 5/16” in height and I have 548 loops of #26 and #22 magnet wire. The main coil resistance is 3.4 ohms and the trigger coil is 8.4 ohms. All components are per the “Complete Beginner’s Handbook”. I am using four – ½” diameter ceramic magnets on a skate wheel. I tried the larger transistor MJL21194G, in hopes of getting more current to flow through the mail coil, and that did not work either. Thoughts/advice?

[Brodie Gwilliam]

21194 should work...do you have core in coil??? those magnets might be a little on small side, whats your resistance on your base? you might need to start pretty low like 50 ohms at first just to make sure , and giver a good quick spin just to make sure... coil will probably have to be pretty close to wheel on it(2-4mm).... you should hear it starting to fire when its working, although with small magnets like that it might not continue to run

[kennygee]

Yes my core is 13mm diameter and packed with 1/16 " wires. My base resistance is according to the Handbook at 680 ohms. I can try bigger ceramic magnets, or I can switch to neo magnets. I understand that neo mags might overwhelm the system. What does the system sound like when it starts to "fire"?

[Brodie Gwilliam]

like a humming or buzzing.... bigger ceramics or lower base resistance should work.... I would lower it to 50-100 ohms just to get started. .. it should run easier at that, and you can later tune or higher the base resistance once you got it working

[Tom C]

your build does not sound like a standard build per the SG beginners book. your magnets are too small and weak for the core. wrong size wire and no Bike wheel. what makes the SG run is induced current in the trigger winding. so your magnets arenot creating a change in flux in the core. you will be happy with the SG if built exactly as JB describes it, otherwise it may just bring frustration, like you are experiencing now...... get yourself some bigger magnets and a bike wheel.... and build a coil with 20 and 23 wire, 470 ohm resistors, mjl21194 transistors....

Tom C

[Aaron Murakami]

I really want to get off the ground with the SSG. I need help with my skate size model: Do they really work with a MPS8099 transistor? I am not getting enough current through the main coil to keep the system running. My coil is 1 5/16” in height and I have 548 loops of #26 and #22 magnet wire. The main coil resistance is 3.4 ohms and the trigger coil is 8.4 ohms. All components are per the “Complete Beginner’s Handbook”. I am using four – ½” diameter ceramic magnets on a skate wheel. I tried the larger transistor MJL21194G, in hopes of getting more current to flow through the mail coil, and that did not work either. Thoughts/advice?

Hi Kenny,

As Tom said, it sounds non-standard.

What you are describing is more like the original basic school girl based on the diagram that John put on Keelynet years ago.

The size of your coil is small, but you should be able to get it to work for the roller skate wheel if that is what you're using.

Yes, that small coil with one power and one trigger winding WILL definitely work with a mps8099, that is what I used for my first Bedini SG build with my pink roller skate wheel.

Here is my first build (the wheel, frame, etc... is the same), but I did use a 2n3055 here way after, but originally it did have an mps8099 and like a 680 ohm base resistor I believe. I also used a 1n914 diode in the original build.



That coil you see has #26 trigger and #23 power windings. It has about 600 turns and the coil is about the same size as yours.

What battery are you running your circuit on? My first battery was a 9v alkaline radio battery and it did work. But at minimum, I'd use a 6v 1.7ah sealed gel cell or 12v would be better like a 7ah sealed battery. Don't worry about charging anything on that small of coil, you won't blow up your transistor by not having it hooked to an output battery.

Assuming your circuit is built right regardless of the npn transistor, you can take the advice you see here and try a lower ohm resistor at the base just to get it spinning to make sure it works.

I hope some of that helps.

[kennygee]

Hi Tom,
I am starting with the school-girl size then will elevate to the bicycle size. I am the guy living in the middle east and the components and right size wire are a little of a challenge to obtain, but I am slowly finding resources. Once I get this running then I will work on the larger one. I like your idea of larger magnets. That plus lower base resistance ought to get me there. thanks.

[kennygee]

Thanks Aaron. Yes I am working on the original basic school girl model and using a 9V Duracell Alkaline. I will try 6v and 12V batteries.

[Brodie Gwilliam]

it will be easier to get running if you start with a 12v on primary side forsure, but higher ya go on primary the more chance you have for blowing transistors up if no charge battery is hooked up

[kennygee]

Hi Brodie,
Thank you for the advice. I will bump up slowly and see how it goes.

[kennygee]

Thank you to those who helped me find success on my skate wheel size model. It runs pretty good.