Bedini Schoolgirl

[Guruji]

multicoil sings

Hi theremart thanks for response.I stayed with the schematic that had posted sephirot in Bedini SG forum page21.I had a 680ohm resistor to the primary coil and changed it to 100ohm as shown in the multicoil schematic that was shown here.So I should leave the primary 680ohms then?
Thanks

[ren]

Hi Guruji,

Im a little confused, you say your are adding 680 ohms to your primary? No resistance should be added to the primary, the primary is the winding which power flows through upon switch closure.

If you mean secondary, which is the trigger wire, then 680 ohm is the base resistance. If your coil is a little smaller then I would suggest 100 ohms to start with. If it is a tiny coil (400 or less turns) then 10- 50 ohms until you get the feel of it. Once you establish a good ohm range wire in a suitable resistor and use a smaller pot for your tuning.

@kickbak. How are you measuring the 4 volts out off the second coil. Or more importantly how is that coil configured? Use something a little stiffer for your coils. PVC works good. Or craft MDF sheets.

[theremart]

RE: 680 ohms

I would like to see your schematic, I just looked at mine it it has 22 ohms at the base with a light for a resistor.

I agree with Ren, 680 is HIGH...

[kick-bak]

@kickbak. How are you measuring the 4 volts out off the second coil. Or more importantly how is that coil configured? Use something a little stiffer for your coils. PVC works good. Or craft MDF sheets.

Second coil is power only with its own transistor. both transistors use common Base and Emitter connections. Diodes off the Collectors join and connect to a analog volt meter from Jaycar so 4 volts would be the total output of both coils. Single coil setup gave me 2.5 volts.

Voltage across the Emitter and Collector of the second coil reads 19 volts ac yet when I connect a neon across there the neon lights up thought these things only lit above 90v?

Voltage across the Emitter and Collector of the bifilar coil reads 17 volts ac and when a noen is connected across there it don't light up 'much confusion'
The coils were quickly made with about 350 turns each, have since beefed up the coil end caps with perspex but the second coil has a few loose windings and is a little pear shaped and hiss's when the SG is running. If I connect the neon across E/C the hissing stops. I suspect the coil is vibrating and will be making a new set of coils soon.

Jaycar supply only 100g spools of 0.6 wire and 25g spools of 0.4 wire so my coils are made up of joined pieces and this wire is a buggar to solder. Have now just bought a 4kg roll of 0.6 and a 3kg spool of 0.4 so will now be able to make decent sized coils.

The spaghetti pic shows a spare transistor in the breadboard. The other transistor is out of shot

[Guruji]

multicoil

Hi guys thanks for help yes with 10ohms to trigger turned.
The thing is that the variable resistor is useless.Cause for rotor to spin I have to turn the variabe resistor to 0.If I turn it a bit it slows down and stops.
Why is this?
What is it's purpose the VR?
Thanks

[EgmQC]

Hi Mart,

Is there a calculation you use to do this or just a guestimate.

Cheers,

Steve

Hi Steve,

To match the coil with the battery you use the C20 rules , so if the C20 rules tell you that you can at max use 0.4 amp then your coil should have a impedance of 30ohm (12v/30 Omh = 0.4 amp). Im maybe wrong but its the way i understand it.

Best Regards,
Eric

[theremart]

Interesting..

Hi Steve,

To match the coil with the battery you use the C20 rules , so if the C20 rules tell you that you can at max use 0.4 amp then your coil should have a impedance of 30ohm (12v/30 Omh = 0.4 amp). Im maybe wrong but its the way i understand it.

Best Regards,
Eric

Yikes....

I have 200 amp hour batteries.... I need 5 amp resistance? I don't intend on using 10 Amps

That would make alot of sense...

[dambit]

Hi Steve,

To match the coil with the battery you use the C20 rules , so if the C20 rules tell you that you can at max use 0.4 amp then your coil should have a impedance of 30ohm (12v/30 Omh = 0.4 amp). Im maybe wrong but its the way i understand it.

Best Regards,
Eric

Hi Eric,

That's a pretty high value. My largest coils only have an impedance of approx 1 to 3 ohms. Also which winding are we talking about, the trigger winding or all of them? I might do some tests by placing a resistor between the power coil and the transistor connection, because the trigger coil already has its own ones for tuning.

I have interpreted you equation as follows.

Ah rating divided by 20 equals C20 rating.
Battery voltage divided by C20 rating equals coil impedance value.

Cheers,

Steve

[dambit]

Yikes....

I have 200 amp hour batteries.... I need 5 amp resistance? I don't intend on using 10 Amps

That would make alot of sense...

Hi Mart,

According to Erics equation, if you have a 12V 200 Ah battery than your coil impedance should be 1.2 ohms.

Cheers,

Steve.

[EgmQC]

Yikes....

I have 200 amp hour batteries.... I need 5 amp resistance? I don't intend on using 10 Amps

That would make alot of sense...

Hi theremart,

Realy nice question, i realy dont know what to answer, like i said i think its the way to match the impedance of the coil with the battery but im not 100% sure.Maybe someone with a better knowledge than me can answer that question because if the output in radiant need to match boths impedance, if one is lower than the other, i dont know if the charging side will have enought, i use currently only small battery (SLA 12V 8amp) so i cant test it right now. If someone can confirm the way to match the coil impedance with the battery that will be nice if im wrong.

Best Regards,
Eric

[dambit]

Hi all,

I just added a resistor to increase the resistance in my coil and the voltage spikes halved in size. I only used a 3 ohm resistor and placed it between the power coil and its connection to the transistor. Not sure if this was the way to do it, but I tried anyway.

Cheers,

Steve.

[EgmQC]

Hi all,

I just added a resistor to increase the resistance in my coil and the voltage spikes halved in size. I only used a 3 ohm resistor and placed it between the power coil and its connection to the transistor. Not sure if this was the way to do it, but I tried anyway.

Cheers,

Steve.

Do it charge the battery at the same speed ? if the answer is yes then its not the spike who charge the battery but something else.

Best Regards,
Eric

[dambit]

Hi Eric,

Not sure, I will test that out.

I thought that the spike is what triggers the radiant when it hits the electrolyte in the battery and that the larger the spike the larger the radiant.

Cheers,

Steve.

[EgmQC]

Hi Eric,

Not sure, I will test that out.

I thought that the spike is what triggers the radiant when it hits the electrolyte in the battery and that the larger the spike the larger the radiant.

Cheers,

Steve.

Its what it should do too but maybe its not that too, who know .

Best Regards,
Eric

[dambit]

It is frustrating not having anything to effectively measure the radiant.

I agree with you that spike isn't the only thing chargeing the battery, but it's all we can measure at the moment.

Cheers,

Steve.