Author Topic: SSG modes COP (Read 21711 times)

MarkE · « **Reply #15 on:** November 06, 2014, 02:59:23 AM »

Where's your coil?

TinselKoala · « **Reply #16 on:** November 06, 2014, 12:23:23 PM »

Very nicely done!

I don't know what the LED will do in place of the diode, though; I got better performance (according to my definition of "better" i.e. lower voltage operation) when I changed from the 1n4148 / 1n914 type switching diode to the 1n5817 Schottky.

Also, try the LED across the coil in both orientations. In either orientation, if there is too much voltage on the input this LED will light up, but when the device is working "properly" (again, by my definition) this LED will only show tiny flashes.

My coil measures about 11 mH and 36 ohms DC resistance. Around 900 turns of #33 on a small bobbin, air core of course.

PhiChaser · « **Reply #17 on:** November 06, 2014, 03:46:40 PM »

The coil I have tried is quite a bit larger I think; 30mm diameter,25mm tall, 62.5mH and 51.6ohms resistance (500+turns of 32? no idea... came out of a shake flashlight). I will post a shot when I get it working properly. Without any battery I can put a neo in the coil and get the main LED to flash when I pull it out of the coil, if done quickly the second LED will eventually start a low flicker.
Some things that I have found interesting; I can get the (main LED) flash if connecting the coil to both ends of the positive rail. I can also get the flash when connecting the coil from the neg input to the pos output (but not the other way around).
I might end up putting that diode back in... I don't have any Schottky diodes.

Phi Chaser

EDIT: For lack of pnp transistors I built another using three parallel caps (2220uf total) and a spot where I can test 'stuff'. I did find a germanium pnp transistor and it let one of the LEDs stay lit for a little while... Uploaded a pic of my second build.
Should this pendulum circuit be a new thread d'ya think?

TinselKoala · « **Reply #18 on:** November 07, 2014, 07:56:11 AM »

The shake flashlight coil is kind of large in inner diameter isn't it? And I found that my build works best with a coil that is nearer 10 or 11 mH and 30-40 ohms. I made a bigger one, around 75 ohms, and it works to pulse OK once the pendulum is swinging, but can barely trigger, so it is very difficult to self start. The one in the videos is closer, and I made a third one that is even closer to 10 mH and 30 ohms and it seems to work the best.
I think that for the pendulum you may want to wind a coil of smaller inside diameter, to focus the field more tightly over the end. The original Nuts&Volts article specified a bobbin, and I actually found the spec sheet for the exact bobbin. I made my own of almost the same size out of a section of phenolic tube 1/4 inch ID and some end plates cut from thin plastic or phenolic sheet.

Bobbin spec drawing below: (inch dimensions, sorry)

PhiChaser · « **Reply #19 on:** November 07, 2014, 09:02:08 AM »

Yep, the inside of my coil is about 1/2" (inches, mms, whatever works!), I took a closer look and it is probably closer to 1000 turns. The neo fits neatly inside the coil so I figured it would probably work okay for the pendulum...
Thanks for the dimensions on the coil you are using, I will see about winding something that has a smaller inside diameter (closer to the specs) and see if that works better.
Hopefully I can figure out some sort of stand to hang the weight and mount the coil on so I can actually 'watch' it working...
I need to order some parts or go find another 'something' to take apart for pieces'; seems like all I have are npn transistors and I'm running low on caps...
PC

TinselKoala · « **Reply #20 on:** November 07, 2014, 03:54:10 PM »

I got my BC556B PNPs from a seller called "thaishine" on Ebay, I've dealt with them several times and am quite happy. Free shipping to US addresses, four days from order to delivery in my mailbox. $3.49 for 50 transistors, delivered! They also respond to emails right away for confirmation, etc.
Search for
"ebay thaishine bc556b"

If you are outside the USA or can wait longer, I see listings for 50 at under two dollars, with a dollar shipping, coming from mainland China or Hong Kong.

Yep, you are going to need a suspension for your pendulum to see the real operation of the circuit, or make a small rotor to try it as a rotary pulse motor. You could probably make a linear version too, with the right magnets and suspension.

synchro1 · « **Reply #21 on:** November 07, 2014, 04:26:53 PM »

One strand for output from a bifilar power coil, looped back to source, should produce some valuable coasting time.

conradelektro · « **Reply #22 on:** November 07, 2014, 05:14:15 PM »

@TinselKoala: I watched your pendulum videos and wonder, why the pendulum stays exactly above the coil.

I know that the pendulum is suspended exactly above the coil. But the pendulum should try to avoid the coil, specially in push mode.

Or is the pendulum in attraction mode, which would always pull the swinging magnet over the centre of the coil core?

Great build!

I got the BC557B instead of the BC556B (which has a lower collector-base voltage -50V instead of -80V, and a lower collector-emitter voltage -45V instead of -65V, the rest of the spec is pretty much the same). Should it also work with the BC557B?

Greetings, Conrad

TinselKoala · « **Reply #23 on:** November 07, 2014, 10:52:15 PM »

Quote from: conradelektro on November 07, 2014, 05:14:15 PM

@TinselKoala: I watched your pendulum videos and wonder, why the pendulum stays exactly above the coil.

I know that the pendulum is suspended exactly above the coil. But the pendulum should try to avoid the coil, specially in push mode.

Or is the pendulum in attraction mode, which would always pull the swinging magnet over the centre of the coil core?

Great build!

I got the BC557B instead of the BC556B (which has a lower collector-base voltage -50V instead of -80V, and a lower collector-emitter voltage -45V instead of -65V, the rest of the spec is pretty much the same). Should it also work with the BC557B?

Greetings, Conrad

The pendulum is suspended by a "V" suspension so it only swings in one plane. It's hard to see this in the video, I'm sorry I didn't emphasise it. The two points at the top are 10 cm apart and the vertical height from suspension to magnet is 20 cm. I adjust spacing by raising/lowering the coil, which is just sitting on a plastic 1/4-20 flathead screw with a plastic nut under the coil. Screw head is glued to the baseboard, coil is raised and lowered by the nut. 3 or 4 mm space between magnet and top of coil. The system operates in repulsion, when the drive pulse happens it pushes the magnet away. The suspension's geometry is such that any disturbance winds up being coupled into the plane of the swing, so it doesn't have to be perfectly accurate in position above the magnet to self-start. As usual, try all four combos of magnet and coil polarity to get best performance with triggering and pulsing.

I guess that the BC557 transistor should work fine as well. The original circuit specified 2n4401 and 2n4403.

Thanks for checking it out! It is really a fascinating little toy, I have it running constantly on the light from the desk lamp which is on anyway. I stop it and let it selfstart every now and then. If it doesn't get a trigger pulse from the passing magnet, it pulses automatically every few seconds, which is how it self-starts.

ETA: If there is too much voltage supplied, the coil will stay on. Also the LED (in my build) should make only tiny, short, barely visible flashes when it is running properly. Also, try the LED both ways, see what happens.

conradelektro · « **Reply #24 on:** November 07, 2014, 11:43:49 PM »

Quote from: TinselKoala on November 07, 2014, 10:52:15 PM

The pendulum is suspended by a "V" suspension so it only swings in one plane.

@TinselKoala: Thank you for clarifying the suspension of the pendulum.

I see, the capacitor C2 1000µF provides a pulse every now and then for the self start.

I just have to build one. As you say, very very neat.

The circuit reminds me of the two transistor circuit for a pulse motor (which does not need any separate trigger means, because the Back-EMF of the drive coil provides the trigger):

https://www.youtube.com/watch?v=OqQSJjRJ6EQ

Greetings, Conrad

nilrehob · « **Reply #25 on:** January 04, 2015, 06:19:46 PM »

Experimental update at:
https://www.youtube.com/watch?v=7MhPPuYuGwc

/Hob

nilrehob · « **Reply #26 on:** January 04, 2015, 06:30:37 PM »

This is my multi-mode circuit I use for easier comparison:
https://2f0f5746-a-62cb3a1a-s-sites.googlegroups.com/site/nilrehob/home/documents/SSG modes COP experiment.png

/Hob

nilrehob · « **Reply #27 on:** January 04, 2015, 09:36:04 PM »

Below are the functions of the switches.

/Hob

TinselKoala · « **Reply #28 on:** January 04, 2015, 11:48:13 PM »

Quote from: nilrehob on January 04, 2015, 09:36:04 PM

Below are the functions of the switches.

/Hob

Very nice, I like your approach. Live comparisons are the best kind.

But which combination is the "OU" combo?

tinman · « **Reply #29 on:** January 05, 2015, 12:46:09 PM »

Quote from: TinselKoala on January 04, 2015, 11:48:13 PM

But which combination is the "OU" combo?

The one in Peters and Arrons book

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Author Topic: SSG modes COP (Read 21711 times)

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