7 circuit Bedini SG

[TheStone16]

Hi All,

I been wondering, what are the difference of having one strand coil, and 7 strand coils with one trigger... does the fields in each strand add up? will create a bigger spike? but it will draw more current ?

Thanks.

[Tom C]

Hi All,

I been wondering, what are the difference of having one strand coil, and 7 strand coils with one trigger... does the fields in each strand add up? will create a bigger spike? but it will draw more current ?

Thanks.

there is only 1 trigger shared between all the transistor bases. esch strand pulls more current so you get a more powerful charger. more current bigger spike, but it is a non linear exponentisal increase.

Tom C

[brodonh]

Hi Tim C and all,

I want to switch my 16" bike wheel to super pole mags and can you say what is best superpole mag spacing?

Thanks.

bro d

[Gpilot]

I built a single circuit bu

[BobZilla]

Just a though here after looking at your original pictures,,,

You may be burning up components when you solder them in. Those huge gobs of solder do not cool as quickly as a joint would on a PCP and also being on a metal plate it is going to stay hot.

To improve on it you may consider drilling tiny pilot holes for your components to connect to. Put a tiny bit of solder in the hole then put the component leg on it while it is cool. Take your iron and touch the leg and the drop at the same time and it should slip right in with minimal heating of the component. This will also result in a more balanced circuit because excessive solder can change resistances.

Good luck ---Bob

[shadow44]

Hi gang! Better late then never! I have a lot of catching up to do. Today I built my first SG. I built it with the help of Johns Book #1. I did it exactly like he said. Cause he says "build it just like this". So I did. or at least as close as I could. I have a close up of the circuit so you can see what I did.

got it all hooked up, and spun the wheel the wrong way. Of course it dident run. then it dawned on me, so I spun it the other way. YeeHaw! she took right off! so to "test" the circuit, I pulled the pos off the charge battery. thats where it went wrong

the 2nd light from the right blinked a couple of times and went out. None of the others came on. I hooked it right back up and it still ran, but slower. so I did a finger temp test on the transistors. 2 on the left were HOT! the others were cold. everything is per spec as far as I can see. So i did some testing, I have no idea how to test BJT's but the values seem consistent except the 2nd one from the left. I put in new diode, no change, new resistor, no change. removed the neon bulb, no change.

eplanation of the picture:
"top of the coil" comes in on the right with the trigger wire coming in through the hole, connected to the resistors. Bottom of the coil connected to the transistors, with the trigger wire coming in thru the hole on the left, connected to the?collector? the pin on the left when upside down
The rest is visible as far as how its assembled.

So what went wrong?

I have got a few days to reflect, as I have to wait on Mouser to ship me new transistors

Any help would be appreciated

pics wont upload. Follow link below.

Also posted here my new SG !! ran then quit.. what did I do wrong?

[alfinip2000]

shadow44, double check your transistor.. it seem it burn away,don't ever release charging battery while SG running, it would end up burn all of your transistor..or weaken it
Cheers,
Alfin

[knagtegl]

Shadow44,

The thing you are doing wrong I think is that if I look at the picture, all your collectors are connected through the cooling plate, you should isolate them ore use separate plates for each transistor.
And of course never ever run without a charge battery, better to short the output then to run it open.
The collector of the transistors is on the middle pin but also on the plate at the back of the transistor, maybe not everyone knows this.

Good luck, It looks good,

Karel

[shadow44]

yes it would appear that way. They are actually unsupported hangin in mid-air. The resistors have sufficient strength to just hold it out about .5 inch above the transistors.

[shadow44]

shadow44, double check your transistor.. it seem it burn away,don't ever release charging battery while SG running, it would end up burn all of your transistor..or weaken it
Cheers,
Alfin

alfinip2000 I looked up testing a trans, and all I found was using a cap tester on your multimeter. My multimeter is a 20 yr old Fluke, and dont have a cap tester. Is there another way to test the transistors?

[shadow44]

Oops you ain't suppose to unhook those charge terminals unless your bulbs can handle the radiant and or you are running 500 miliamps or less on the input. First thing I did was check the parts you talked about and then replaced the transistor, well I tested mine first.

You mean you unhooked the pos before your ever got a charge voltage pumping the battery???

Nice copy of the JB bike wheel.

Mike

Yes I unhooked it... Should not have done that huh. I thought I had seen where that was how you tested the circuit, if they all lit up you had it right. the wheel was cranking pretty good, faster than I expected, so maybe it just burnt things. I'm so disappointed. Its going to be days before I can try it again....

Thanks for the compliment I have several days in making that wheel. Hours studying every word picture and detail. but it should be worth the effort when its done.

I need a way to test the transistors, I dont have a capacitor tester, just a Fluke 77 multimeter. maybe I could find a good one left, and get it running on it till I get my new ones.

[John_Koorn]

Shadow, you can use the ohms test on your meter. Measure between collector and emitter. If you get 0 ohms your transistor is blown.

John K.

[knagtegl]

Shadow44,

The reason why there is only one neon going on is that all your collectors are connected by the screws on your cooling pate.
The neon with the lowest voltage will light up and consume the radiant. If you disconnect that neon the next one in voltage will come on
I think, don't try because you never want your neon's on.

You can test a transistor with an ordinary ohm meter and measure the resistance between the base and collector and between the base
and emittor the should be around the same value in one direction and not giving a reading the other direction.

And the wheel should be running in both directions!

Karel

[shadow44]

Shadow, you can use the ohms test on your meter. Measure between collector and emitter. If you get 0 ohms your transistor is blown.

John K.

Yep. dead short on all of them. I dident pull them out yet, they are still soldered in. I'll take them out in a bit and double check. I was hopeing to find a good one and get it running on just 1 circuit till the new ones get here...

Thanks for your help.

[shadow44]

Shadow44,

The reason why there is only one neon going on is that all your collectors are connected by the screws on your cooling pate.
The neon with the lowest voltage will light up and consume the radiant. If you disconnect that neon the next one in voltage will come on
I think, don't try because you never want your neon's on.

You can test a transistor with an ordinary ohm meter and measure the resistance between the base and collector and between the base
and emittor the should be around the same value in one direction and not giving a reading the other direction.

And the wheel should be running in both directions!

Karel

Well your partially correct. there actually is an insulator. (used ones) under each trans. but I checked the resistance and all of the collectors have connection to the heat sink. I have new ones ordered, just had not got them yet and was impatient. so how hot should they get if I just let them "free air" cool? would they get too hot in a few minutes just to test it?