Bedini Ferris Wheel Regauging Motor

[hherby]

Paul, I just went back through my notes from the conference and I think you got it!
my notes do show P channel. So unless I wrote it down wrong you just solved my major hurdle. I don't have any P-channel so looks like I'll be a few weeks out.

Thank's
Les

I reviewed my pictures from the conference and JB was using a pair of IRFP260's in the comparator cap dumper.

Comparator was an LM741CN

Alex

[minoly]

With no other instruction, I just decided to start adding different air coils. I should have done this long ago. if anyone is still having problems getting more out of the 3GT or even just running a single coil off of the Bedini Cole switch on a monopole wheel - just start trying out different coils in parallel with the main power coil but away from the wheel, add a core, remove the core - it does not take long to get the hang of the tuning.

Patrick

[Les_K]

Hi Les,

I just finished watching #28 and printed off the circuit that Ron posted earlier in this thread.

It is not clear to me that the mod adding N-channel mosfets is correct. At present, I think that the mosfets are leaching energy from the battery continuously.

I stumbled across this problem myself just a while ago. N-channel mosfets have an internal diode from source (anode) to drain (cathode) which appears to allow current to flow continuously if you hook the drain to the battery -ve.

Here is a simulation of the simple circuit that I ran into trouble with:

simple lamp circuit

and here is a simulation of important bits of your circuit:

abridged pulser

I thought that I saw JB draw p-channel fets on the video, but I need to view it again.

pt

Paul, I just went back through my notes from the conference and I think you got it!
my notes do show P channel. So unless I wrote it down wrong you just solved my major hurdle. I don't have any P-channel so looks like I'll be a few weeks out.

Thank's
Les

[pault]

mosfet mod in question

Well after running this circuit for a few months now I have to say it makes a real lousy battery charger. The SCR circuit of John k. out does it by miles. Anyone got any ideas?

Les

Hi Les,

I just finished watching #28 and printed off the circuit that Ron posted earlier in this thread.

It is not clear to me that the mod adding N-channel mosfets is correct. At present, I think that the mosfets are leaching energy from the battery continuously.

I stumbled across this problem myself just a while ago. N-channel mosfets have an internal diode from source (anode) to drain (cathode) which appears to allow current to flow continuously if you hook the drain to the battery -ve.

Here is a simulation of the simple circuit that I ran into trouble with:

simple lamp circuit

and here is a simulation of important bits of your circuit:

abridged pulser

I thought that I saw JB draw p-channel fets on the video, but I need to view it again.

pt

[Les_K]

Did I miss a post some where? 3 times per second still sounds too fast.

It was mentioned here several times and also on the video series.

looks like you did a lot of work while you were under the weather.

I did most just before, but couldn't post. of course I had a little time to think about the results...

aside from doubling the voltage, it seems there should be a minimum joule/dump depending on the impedance and size of the battery bank you are dumping to as well.

This is an excellent observation, I wish JB could answer this one. There are aspects of this I do not understand. However I can say from my knowledge (so far as it goes) that I can see the slope of the discharge on my scope. This gives me an idea of what is happening. But JB said at the conference that he was trying to follow the voltage all the way to the top of the capacitor no matter what speed it was running. and at a certain point in time he wanted to dump the most possible current in terms of joules he could to the battery. since his model could not get there like the big wheel he then had to add the extra Air core coil to shift the impedance around. (as a side note and who knows why I never thought of it before...DUH! If you have a ferris wheel see if your outside coils are warm and the main coil is cold. That's what mine are.) So there is much about this that I am still trying to understand.


Do you notice any ability to control where along the "motors" wave form the comparator dumps at?
thanks
Patrick

The comparator circuit does three things at the same time as JB explained at the conference. it is looking at the output battery, it's looking at the capacitor in terms of voltage, and it's looking at the frequency of the wheel. the step is being controlled by each magnet thats passing, thats the frequency. the hall is triggering the bipolar circuit but but the magnetic field is generating the pulse. the comparator is detecting the magnetic passages of the coil inductance wise. It is actually the Zeners causing the switching to take place so those have to be considered very carefully. on my test machine and on my Ferris wheel, I can set the the pulse width with the hall magnets by moving them closer or farther from the hall. I also have an adjustment to move the hall forward and backward in relation to the rotating wheel. In essence a dwell if you will. So like I told John at the conference this machine is sophisticated elegance because it looks so simple a six year old could build it but the complexity of what is going on to make it work is going to baffle us all for years to come. A thorough class on tuning would be a significant leap for this technology.


So all I can really say Patrick is that those are excellent, astute, questions, That I am far from qualified to answer. I have done my best so hopefully that will help.

Les

[minoly]

Hi all,
I have been ill the last few days so sorry I didn't get back sooner.
Since I posted this I built a test bed and did some experimenting.
I am using a 5" MDF wheel with four ceramic magnets. It runs at about 2300rpm.
I had a coil that was four strands one of which was Iron. I used the comparator circuit and that was very nice to see improvements changes etc. as I played with the machine.
The output cap was dumping at about 8 times a second. I then reversed one strand on the coil so current was flowing reverse of the other strands and it all but quit running.
I then added resistors starting at 100 ohms until I got to about 10k at which time it was dumping at just over 11 hz. Then I took a ceramic magnet and held it around the coil moving all over the windings. No change. North or south no difference. on the end of the coil even touching the end of the core no difference. Then I took a piece of Iron that came out of a hard drive and did the same thing nothing until I touched the back of the core. It all but killed the machine. I think the dump was probably about 1 every ten seconds and RPM's dropped like a rock.

I concluded from this that I had way to much iron core for the windings that were only 120ft. And it was using 500ma. I made a new coil same core size but doubled the wire length. As you would imagine the input went down. It now ran at 370ma. BUT.... The cap dump was now at 18.6htz. Whoa! more out less in! I can conclude that I have been running way to much Iron for the windings.

The next thing I did was add some capacitance across the R5 and R6 resistors. this allowed the fet's to stay on long enough for one pulse of the coil to pass to the battery before starting to charge the main cap again. This charging seems a significant improvement over just the cap dump by itself.

Also I went from 120uf on the main cap to about 680uf which dropped the dump frequency to about 4 times a second. This also seems to have helped the charging. Takes longer to charge but seems to be a much deeper charge. Or the battery can sustain for a much longer period under load.

Right now I think the comparator circuit is a wonderful tool for tuning. While watching the frequency of the cap dump on the scope you can immediately see your results.

Now I am looking at what JB said, that the charge should be twice the battery voltage. So in my silly mind I calculate it this way. I subtract the bottom of the dump. which is typically about 14 or 15 volts. (you have to be at least 2 volts over the battery to get it to take a charge.) then I add 24 volts. so I am dumping the cap when it reaches about 38 to 42 volts. I'll need to order more caps so I can try 24- 30 volts and see what that does and stay in the three times a second range.



Les

Did I miss a post some where? 3 times per second still sounds too fast.

looks like you did a lot of work while you were under the weather.

aside from doubling the voltage, it seems there should be a minimum joule/dump depending on the impedance and size of the battery bank you are dumping to as well.

Do you notice any ability to control where along the "motors" wave form the comparator dumps at?

thanks
Patrick

[Les_K]

Update SCR vs Comparator

Hi all,
I have been ill the last few days so sorry I didn't get back sooner.
Since I posted this I built a test bed and did some experimenting.
I am using a 5" MDF wheel with four ceramic magnets. It runs at about 2300rpm.
I had a coil that was four strands one of which was Iron. I used the comparator circuit and that was very nice to see improvements changes etc. as I played with the machine.
The output cap was dumping at about 8 times a second. I then reversed one strand on the coil so current was flowing reverse of the other strands and it all but quit running.
I then added resistors starting at 100 ohms until I got to about 10k at which time it was dumping at just over 11 hz. Then I took a ceramic magnet and held it around the coil moving all over the windings. No change. North or south no difference. on the end of the coil even touching the end of the core no difference. Then I took a piece of Iron that came out of a hard drive and did the same thing nothing until I touched the back of the core. It all but killed the machine. I think the dump was probably about 1 every ten seconds and RPM's dropped like a rock.

I concluded from this that I had way to much iron core for the windings that were only 120ft. And it was using 500ma. I made a new coil same core size but doubled the wire length. As you would imagine the input went down. It now ran at 370ma. BUT.... The cap dump was now at 18.6htz. Whoa! more out less in! I can conclude that I have been running way to much Iron for the windings.

The next thing I did was add some capacitance across the R5 and R6 resistors. this allowed the fet's to stay on long enough for one pulse of the coil to pass to the battery before starting to charge the main cap again. This charging seems a significant improvement over just the cap dump by itself.

Also I went from 120uf on the main cap to about 680uf which dropped the dump frequency to about 4 times a second. This also seems to have helped the charging. Takes longer to charge but seems to be a much deeper charge. Or the battery can sustain for a much longer period under load.

Right now I think the comparator circuit is a wonderful tool for tuning. While watching the frequency of the cap dump on the scope you can immediately see your results.

Now I am looking at what JB said, that the charge should be twice the battery voltage. So in my silly mind I calculate it this way. I subtract the bottom of the dump. which is typically about 14 or 15 volts. (you have to be at least 2 volts over the battery to get it to take a charge.) then I add 24 volts. so I am dumping the cap when it reaches about 38 to 42 volts. I'll need to order more caps so I can try 24- 30 volts and see what that does and stay in the three times a second range.



Les

[Ron Chase]

Les,

I found John K's SCR circuit in his files on the monopole 2 users group.

Ron

[minoly]

Les I don't know that much about the cap dump, but are you employing the tuning air core on your machine?

do you mind describing the behavior of the cap dump. do you have a scope shot of the stair step dump?
what voltage does it climb to, what size cap, what voltage does the cap end at how long does it take to complete the dump, what is the freq of the dump, does it shut off hard etc...
I'm "currently" (lol) in the middle of watching EFV 28.
thanks,
Patrick

[Ron Chase]

Well after running this circuit for a few months now I have to say it makes a real lousy battery charger. The SCR circuit of John k. out does it by miles. Anyone got any ideas?

Les

Hi Les,

Over the holidays, I experimented with several variations of cap dump circuits and had the same experience as you. Do you have a copy of John K's circuit you can post?

My 5 foot wheel charges great in coil inductive pulse mode but, I would like to get it running in cap pulse mode to compare the difference between the two. As I understand it both modes charge well but create different structure on the battery plates.

Ron

[minoly]

Well after running this circuit for a few months now I have to say it makes a real lousy battery charger. The SCR circuit of John k. out does it by miles. Anyone got any ideas?

Les

Les I don't know that much about the cap dump, but are you employing the tuning air core on your machine?

do you mind describing the behavior of the cap dump. do you have a scope shot of the stair step dump?
what voltage does it climb to, what size cap, what voltage does the cap end at how long does it take to complete the dump, what is the freq of the dump, does it shut off hard etc...
I'm "currently" (lol) in the middle of watching EFV 28.
thanks,
Patrick

[Les_K]

SCR vs Cap dump

Well after running this circuit for a few months now I have to say it makes a real lousy battery charger. The SCR circuit of John k. out does it by miles. Anyone got any ideas?

Les

[Les_K]

Oops. The pinout on the comparator.
pin 1 - output
pin 8 - vcc
Pin 4 - gnd
pins 2 & 3 ok

Les

Sorry looking at the wrong schematic....

Never mind all is well....

Les

[Les_K]

Nice work Ron,
I think it's a good schematic to work from.
I noticed a ticking noise in the battery when this is running. I understand that's a good thing, but unless JB can comment who knows.....

Les

Oops. The pinout on the comparator.
pin 1 - output
pin 8 - vcc
Pin 4 - gnd
pins 2 & 3 ok

Les

[Les_K]

Hi Les,

Please check over this schematic and let me know if there are any errors.

Also, thanks again for the coil and magnet layout. Maybe I can make some changes this weekend and get rolling again.

Ron

Nice work Ron,
I think it's a good schematic to work from.
I noticed a ticking noise in the battery when this is running. I understand that's a good thing, but unless JB can comment who knows.....

Les