Bedini Ferris Wheel Regauging Motor

[Ron Chase]

Hi Brent,

The resistor values that you have in place now are for smaller wheels. The values that Alex suggested in post #1589 will work for your 6' wheel. I've included a picture of my motor board with the higher value resistors 3.3K and 2.7K both 5W and I have no resistor heating problems on my 5' wheel. The board layout is very close to what you and Scott and I worked out, much thanks to JB for letting the conference participants take a peek under the hood.

You will probably want to add an additional set of transistors to help carry the load and maybe take a look at some base resistors to balance out how hard the transistors turn on. Are they beta matched?

When I first fired up my wheel I felt like the transistors were staying on too long so I reduced the timing pulse width by moving the hall switch away radially from the center of the timing magnets. It helped with the current draw and I still had plenty of adjustment for RPM.

Thanks again for sharing, Ron

Give me a call if you have time

[BrentA929]

Bedini/Cole circuit issues

@All,

Not much to report, other than some frustrations with the Bedini/Cole circuit...

We can't seem to get a grasp of why the resistors are getting so HOT (200+ degrees) and why when a neon is attached across the transistors, one side will flash! Do these issues have something to do with each other?


Here is a video showing what is going on...Bedini/Cole circuit issues video


Real hard to run any prolonged tests until we can figure this out! HELP!



Thanks, Brent


P.S. Oh and BTW, the circuit doesn't get even remotely warm on a smaller coil nor do the neons flash. What are we missing? Bigger switch? More transistors?

[Les_K]

NIKOLA TESLA - Google Patents

I checked this earlier and you had posted some other stuff and I was interrupted and had to leave for a while now the other info on the coils has vanished. What happened?

Les

[nvisser]

NIKOLA TESLA - Google Patents

[Les_K]

Pancake coils

Ok John,
I think I am seeing a little about this now
Hey john i was just thinking about your earlier post about aircore
pancake coils

Air core vs iron core. Air core has little or
no drag at startup then builds cogging as it speeds
up. This is why aircore with big BIG honking neo's
is popular with windmills. But also the power output
is low until you get to a higher rpm correct?

Now I have zero experience with pancake coils.
I know that in terms of drawing in the surrounding energy
they were used by tesla. But could you or anyone suggest
where I might get or read more information about this.
Pancake coils are always a topic but I don't think I'm getting the whole
piece of pie on the subject.

Thanks
Les

[wheatbelt.radio]

crap can somebody delete that pointless spam :P

[wheatbelt.radio]

o-m-g

they are 21193

cant believe i didnt notice before, i wonder if that means reverse they pull negative through the coil instead of positive,

better try too decode the new datasheet... some input on that would be great if anyone is familiar ?

[wheatbelt.radio]

im wondering if i need a larger trigger strand too force these transistors on - being that the power strands are only 8 - 12 ohms - and the same length as the trigger

but i really dont think its self oscillating because i remove the magnet wheel from the vicinity, then switch the power off and on -

and immediately its powering the coil - so i adjust the 20k POT from min too max and it just varies the current consumption on the analogue gauge - never drops too zero untill i switch it off again.

[wheatbelt.radio]

trannys blow

http://www.imagehosting.nu/images/ssg.jpg

Gday,

simple test rig, ive tried plenty of arrangements and most work, however not easy finding an effective combination for battery charging

i thought i had a coil geometry pretty well sorted, with the usual transistors, 3055s, tip31's mje 2995's, however non want too pump enough juice through the coils so i got some bedini specials, the TO-340 = MJL21194

the only previous TO-340's ive tried are from my old subwoofer, and they work great, best of the bunch... but these new MJL21194's ... cant get them "working" at all, they seem too be working like a linear - always on switch... like a dimmer switch for a light bulb, they dont react too the trigger, they are always on and dont turn off - just turn down with the pot - but i hear nothing - usually they scream when in self oscillation mode, and you can stop the oscillation by fiddling with the POT, but its just a dimmer... @-(

and ive pulled out many old coils of all shapes sizes that worked great with other ssg's... but i cant get these MJL's working on anything at all...

and they are from ebay, but from the US and full price ?... so... does my description ring any bells ?

today my perfect spools are running @ 8 ohm and @ 12 ohms

2 strand each,, + trigger, wound together

[BrentA929]

Bedini GT3

@John B,

We have done the quartz light test...

Why do you think our resistors are getting so HOT? Any ideas? Are 2-watt resistors enough for our 6' build? Is that what you have on the 12 footer?


@Mark P,

Looks like you are making some head way! Your build is really professionally done!!!


@Eric N,

Thanks for your input! You don't realize how many times I have read and re-read what JB says, but I appreciate your insight!


@Alex,

Thanks for the information. One thing that you have to keep in mind with the comparator circuit, is that there is always charging battery voltage across the dumping cap. So, you will never be able to dump all the energy from the cap, but we don't know if what we are seeing is adequate. We are still experimenting!


Thanks to all, Brent

[hherby]

We just wanted to give everyone a quick update on where we are at with the comparator circuit. We have been playing with it while we wait for a few components for the motor drive circuit. We have the capacitor dumping a lot better. We have been playing around with capacitor values. Here's a quick video:

Bedini Cap Dump Comparator Circuit

We aren't sure if we have it all worked out completely, but we feel we are getting pretty close. We have it dumping down to about 17V for the 12V system we are testing on. Thank you again JB for explaining this circuit at the conference. We could have never gotten this far without you!

@JB - Can you suggest any values for the capacitor in question on the video to try to get the best dump? Also, you suggested to try a 660 ohm resistor for the motor drive. Is that in place of the 220 and for the 36V 6ft wheel?

Thanks,
Scott

Hi Scott,
I'm sorry I don't have the time to quote references but I just wanted to relay a few thoughts.

A cap will dump something like 99.3% of it's energy in 5 time constants and 63% of it's energy in just 1 time constant. It seems to me that dumping the cap for 1 to 2 time constants will give you the most bang for your buck and also shorten the time it takes to charge it back to the dumping voltage. JB always talks about charging the cap to twice the charge battery voltage. Someone earlier in the thread (I believe vissie) did some calculations on the cap discharge on the 16GT and found it was not being discharged down to battery voltage. I believe JB was using this property to maximize energy transfer from the cap to the charge battery. So the discharge during the 1st time constant gives the charge battery a good hard slap. As the energy is proportional to the square of the voltage in the cap, the rate of transfer of energy from the cap to the charge battery decreases by the square of the voltage. The idea would be to balance the charge time to the discharge time to accomplish the highest rate of energy transfer. This would be something that would have to be tuned specifically for each machine and it's battery setup via Cap size and comparrator settings.

Comments welcome.

Thanks
Alex

[ErikN]

@Erik N,

After spending a couple of weeks working with JB side by side on getting your build working, are there any suggestions you can make for those of us that are working on the BFW? Do you think you could have done it without his help? Starting to wonder if we need to take a road trip! Ha!

Hi Brent & Scott,

Nice talking to you at the conference. It sure is nice to put faces to names.

As for suggestions, LISTEN (and/or reread) when John says something and don't take it out of context. For me, things don't always sink in right away, so I try to replay things in my head. Then I try to put my thinking cap on.

On tuning....If I were working with your large machine and 3 coils, I'd get it running with the primary coil first and note how fast the wheel turns. Then I'd add the second coil and see if it speeds up. Same with the 3rd coil.

Erik

[Rl2003]

Guy's

I am glad to see that someone else is still working on this project.
It has been awhile with little discussion, I have made a couple video's
and some changes to the GT3.

1) I added about 30lbs to the rotor. I had a old carbon fiber disk wheel
and filled it with a type of concrete. (quick setting) Seems to have a lot of
torque but I have not tested that yet. (balanced by adding small weights
to the back side)
2) I changed the timing wheel slot to about .03125 gap from over
double that. (Cap charging does not seem to be as fast as before.)
Still need some more testing to see what is better. But it does charge well for
the small amount of draw on the run batteries. 3.6 watts aprox.
3) Added an additional neo to the back of the ceramic. I think I will try
some bigger sizes on the back, but I need to order some that will fit. I
think that this needs some serious looking into. I was playing with another
project that uses ceramics, shielding and neo's and it is quite interesting.
You can see my short magnet video showing the difference.
4) I have the coils in series. The amp draw comes down quite a bit from
running all of them in parallel.
5) I have a much lager cap. 63v 22000uf. Quite a pop when discharging this
cap to steel. Makes a fine spot welder.

Some advice I would have for any one building or thinking of building this.
This is an excellent opportunity to learn a lot, and I am glad I have spent
the time to play with this.
I would make my slave coils as big as the master I made,
and the master twice the size. I would make the iron core of the coil
bigger, double the area size, and wider than the width of the ceramics that
you use.
Of course larger neos on the back of the
ceramic magnets. Make sure all of the magnets are as close to 22.5 deg.
from center to center. Runs better when it's right on.
I also moved the master coil about 2 degs. over from bottom dead center.

Here are my latest videos.
Mark P.

GT3 take 33 - YouTube

GT3 take 34 - YouTube

Ceramic Neo - YouTube

GT3 take 37 - YouTube

[txaggie00]

Cap Dump Comparator Circuit

We just wanted to give everyone a quick update on where we are at with the comparator circuit. We have been playing with it while we wait for a few components for the motor drive circuit. We have the capacitor dumping a lot better. We have been playing around with capacitor values. Here's a quick video:

Bedini Cap Dump Comparator Circuit

We aren't sure if we have it all worked out completely, but we feel we are getting pretty close. We have it dumping down to about 17V for the 12V system we are testing on. Thank you again JB for explaining this circuit at the conference. We could have never gotten this far without you!

@JB - Can you suggest any values for the capacitor in question on the video to try to get the best dump? Also, you suggested to try a 660 ohm resistor for the motor drive. Is that in place of the 220 and for the 36V 6ft wheel?

Thanks,
Scott

[BrentA929]

Video 2

Dave,

Good point!!!

Here is take two....Test 2 video


Thanks, Brent

Hey Brent,

Wouldn't it be more relevant to do the quartz light test using the same switch that you have driving your BFW?

I think the idea might have been to see if your transistors are switching on fully and that you are getting enough voltage to the coil. Just hook 12 volt batteries up in place of the 36 volt bank to see if you are getting enough of a voltage drop across your load.

Dave