Bedini Ferris Wheel Regauging Motor

[Les_K]

Ok, Got a basic comparator circuit running. Had to go back to the circuit on page 47. Figured out how to change the Transistor and SCR over to fets. I then looked at the h11d1 and discovered it was pulling something like 30ma.
Finally remembered a little electronics back in the old days called darlington pairs.
With a MPSao6 in a darlington with the opto I was able to get the current way way down. I then attacked the Zeners and got them very close to the knee. so I am using a very small amount of power. I was very surprised to find out that I could get a very low current with a larger 3watt 5929 than with a smaller 1 watt zener. Been a long time since I did much analog so it has been a real brain worker.... the circuit is not what I would call stable though. It seems to drift a bit has some misfires and sometimes turns off and starts charging the cap before it is discharged to the battery voltage. Typically about 2 volts of the battery though. Anyway just an update.

The main thing I wanted to ask though, (If your still around and watching John) is that I remembered that the wooden wheel at the conference had the outside coils with something like 3000 turns of #20 wire at 19 ohms. and the aircore had something 1100 turns. But I don't remember any of the rest of the numbers on the coils. I am (Can you believe it) thinking of another machine and would like to try the three ceramic setup. Could you tell us a little more about those coils John?

Thanks
Les

[graphitebone]

catching up

just waiting on a few more parts.

[Les_K]

just waiting on a few more parts.

Nice work.
I have noticed the three transistors and JB had them on his at the conference, could you tell me a little about that? What transistors are you using etc?

Thanks
Les

[Ron Chase]

Bedini/Cole Circuit

Hi Les,

This schematic should answer most of your questions.

Ron

[Les_K]

Wow, Very nice. I was wondering if it was the BD243,s and 44's He uses those a lot in his patents. I didn't see much here about that part is there another place where this was discussed somewhere?

Les

[Ron Chase]

Bd243,244

Les,

I'm sure it must have been discussed elsewhere but I don't know where. A lot of the circuit I posted was figured out by Brent and Scott on this thread.
We worked on it and eventually got it right. It runs our big wheels nicely. My 5 foot wheel only draws 750mA. I'm still not happy with the charging but there are many variables to ponder.

Ron

[Les_K]

The charging is interesting. I had three 20AH batteries in series on the back end the were less than 11 volts. in 20 minutes they were fully charged and cold boiling. 1.2 amps on the wheel. Can I do it again........?

This is a very tricky machine when tuning is involved. but when it hits...Wham!

By the way I was looking at the schematic and This drawing is really nice. I have been looking around for something what did you use to draw it up with?

Les

[nvisser]

Ron
Why will you use that high wattage resistors and parallel driver transistors if your wheel only draws 750ma. Surely the idea of that circuit is to supply the wheel with lots of current without overheating the components.
Vissie

[Ron Chase]

Misc.

The charging is interesting. I had three 20AH batteries in series on the back end the were less than 11 volts. in 20 minutes they were fully charged and cold boiling. 1.2 amps on the wheel. Can I do it again........?

This is a very tricky machine when tuning is involved. but when it hits...Wham!

By the way I was looking at the schematic and This drawing is really nice. I have been looking around for something what did you use to draw it up with?

Les

Hi Les,

Thats impressive charging! Do you have a picture of your present machine you can post. What type of circuit are you using to dump to the batteries? What size are your coils? How do you tune? I've heard reference to using air coils for tuning but no details.

My coils are half the size of JB's ferris wheel coils but my charging is anemic. I'm clearly not tuned and I think the comparator cap dump circuit, I'm using is not quite right. See below. Brent and Scott get most of the credit for the circuit. I have no idea if this circuit is what JB is really using on his ferris wheel or not but it does function and is very finicky.

I have used AutoCad forever so over time, I've built up a symbols library for schematics but its not the best for electronics. There are much better CAD programs out there for schematics (google Electronic CAD). I mainly use AutoCad for simple mechanical drawings. I converted the AutoCad file to PDF for posting.

Ron

[Ron Chase]

Ron
Why will you use that high wattage resistors and parallel driver transistors if your wheel only draws 750ma. Surely the idea of that circuit is to supply the wheel with lots of current without overheating the components.
Vissie

Hi Vissie,

You are right. The resistors do not have to be 5W and depending on the size and number of coils you can reduce the number of parallel transistors. The circuit as shown will drive JB's big 14 foot ferris wheel and can also be used to drive a good sized window motor.

My coils are half the size of JB's so at 750mA current draw, I could easily use just one set of switching transistors and also lower current rated transisors.

I tend to over design because often I will use the same circuit I've hand built to run other devices with possibly greater current requirements.

Thanks for your input, Ron

[Les_K]

Hi Les,

Thats impressive charging! Do you have a picture of your present machine you can post. What type of circuit are you using to dump to the batteries? What size are your coils? How do you tune? I've heard reference to using air coils for tuning but no details.

My coils are half the size of JB's ferris wheel coils but my charging is anemic. I'm clearly not tuned and I think the comparator cap dump circuit, I'm using is not quite right. See below. Brent and Scott get most of the credit for the circuit. I have no idea if this circuit is what JB is really using on his ferris wheel or not but it does function and is very finicky.

I have used AutoCad forever so over time, I've built up a symbols library for schematics but its not the best for electronics. There are much better CAD programs out there for schematics (google Electronic CAD). I mainly use AutoCad for simple mechanical drawings. I converted the AutoCad file to PDF for posting.

Ron

My machine has not changed much since the pictures I posted earlier.
I am pretty much out of space to add more here as well.
It is still using the circuit John K. posted a while back.

The tuning was not so hard. I used some masking tape on the top of the coils to show where the edge of the magnets should be. So when the magnet over the center coil was lined up with the edge of the tape, I could adjust the right and left coils until each of those magnets edges were lined up to each piece of tape. This got me very close and then to verify that I had it I gave the wheel a little spin. It acted like the coils and magnets were not present there was no cogging whatsoever. Getting the hall aligned was a whole different ball game. fortunately I had made that with a casing that had micro adjustable screws. But the key point was to get it to kick backwards then kick forward. after that it was just slight changes.

The air-core coils were at the conference on the machines there. in that case JB had a different setup on the magnets. with no neo's. And Erik's machine had huge magnets in close proximity. I noticed on my machine as I added Neo's on the back of the ceramics that the current would go down and the charging would go up as I stacked thin neo's on top of each other. I ran out of them but I think I could have improved on my machine with one more layer of them on the back of the ceramics. Anyway I don't know but I think the AirCore's were to compensate for something related to this.

If you look back to my posts on my build I have very small wire for my coils. It was all I had at the time. Boy I would like to make a big coil!

One other thing about your schematic for the pulser. It is different than mine. but the important thing is how it looks on the scope. Over the last few days because of what I learned on the Monopole group I have been testing the output. I almost ruined a new battery because as soon as the cap is dumped the comparator has to switch. if it stays things do not work so well. So take a look at the cap dump to the batt and see how it is working.
Mine was a bit finicky at first as well now it's running rock solid. The right hysteresis is important and it looks like you have no feedback on the op-amp. I am using a comparator. TLV3702IP. Mine is running under 3ma. so I only have one resistor over 1/4 watt. on the back side where you are using a BD243C I am using an MPSA06 in darlington with the H11D1. But My circuit is only running on a 12 volt system at present.
So you might have a better choice there. Maybe I need to clean up my draft and send it to you so you can make a nice schematic for us...

Les

[Ron Chase]

Schematic

My machine has not changed much since the pictures I posted earlier.
I am pretty much out of space to add more here as well.
It is still using the circuit John K. posted a while back.

The tuning was not so hard. I used some masking tape on the top of the coils to show where the edge of the magnets should be. So when the magnet over the center coil was lined up with the edge of the tape, I could adjust the right and left coils until each of those magnets edges were lined up to each piece of tape. This got me very close and then to verify that I had it I gave the wheel a little spin. It acted like the coils and magnets were not present there was no cogging whatsoever. Getting the hall aligned was a whole different ball game. fortunately I had made that with a casing that had micro adjustable screws. But the key point was to get it to kick backwards then kick forward. after that it was just slight changes.

The air-core coils were at the conference on the machines there. in that case JB had a different setup on the magnets. with no neo's. And Erik's machine had huge magnets in close proximity. I noticed on my machine as I added Neo's on the back of the ceramics that the current would go down and the charging would go up as I stacked thin neo's on top of each other. I ran out of them but I think I could have improved on my machine with one more layer of them on the back of the ceramics. Anyway I don't know but I think the AirCore's were to compensate for something related to this.

If you look back to my posts on my build I have very small wire for my coils. It was all I had at the time. Boy I would like to make a big coil!

One other thing about your schematic for the pulser. It is different than mine. but the important thing is how it looks on the scope. Over the last few days because of what I learned on the Monopole group I have been testing the output. I almost ruined a new battery because as soon as the cap is dumped the comparator has to switch. if it stays things do not work so well. So take a look at the cap dump to the batt and see how it is working.
Mine was a bit finicky at first as well now it's running rock solid. The right hysteresis is important and it looks like you have no feedback on the op-amp. I am using a comparator. TLV3702IP. Mine is running under 3ma. so I only have one resistor over 1/4 watt. on the back side where you are using a BD243C I am using an MPSA06 in darlington with the H11D1. But My circuit is only running on a 12 volt system at present.
So you might have a better choice there. Maybe I need to clean up my draft and send it to you so you can make a nice schematic for us...

Les

Hi Les,

I'd be happy to draw up a schematic of what you have. It goes pretty quick.

I'm running 36V on my wheel and there is a slight warming of resistors but not enough to warrant using 5W resistors. However the bigger wattage resistors did save my bacon one time when I inadvertantly ran the wheel without the coils hooked up. Some of them got quite warm!

The comparator is definitely not turning off after it turns on initially. I can see that with my scope so I will look into providing some feedback. Thanks. I also thought a 10K pullup resistor on pin 6 might stabilize it a bit. We'll see!

I have good adjustment range with my timing wheel and hall effect sensor.

Thanks for the info on the air core's.

I have my outside coils offset from the magnets but, I'm not confident they are in the correct positions. I haven't so far been able to get much kickback. The left slave coil is 1/2" in towards the center coil and the right slave coil is 1/4" away to the right of the center coil based on the postings on this thread but I was never confident in those figures. I've moved them around a bit but so far no dramatic improvments. When you positioned the masking tape on your coils what measurments did you use for the edges of the magnets relative to the coils?

Thanks, Ron

[Les_K]

Ok this is hard to do verbally. A picture really is worth a 1000......
Starting on the right coil standing in front of the wheel so that it is turning counter clockwise.

The right side coil: looking at the coil, the core part. I start from the outside edge (furthest out from the center coil) then come in 1/8th inch.

The left side coil: looking at the coil, the core part of course. start from the outside edge (furthest out from the center coil) then come in 3/4 inch.

Center coil: Slice down the center.

Hope that helps!

Now here is the best resolution I could get for the schematic. I hope you can see the components etc.

[Les_K]

Ok that didn't so so well.....
Here is another maybe that will work better. I am using a 1n5347 3 watt for D2.

Les

[Ron Chase]

Les,
Thanks for the info on the coils. I'll re-align with those locations.

I started on the schematic and I have a few questions.

1. Zener value-D3
2. LED part #-D4
3. Opto coupler part # (H11D1 ?)
4. Q1 part#
5. Q2 and Q3 JFET part#

Thanks, Ron