Question on SSG operation

[faramog]

Built my first SGG:
Coil is 24 & 20 swg aprrox 480 turns and steel nails as the core
25 inch Bike wheele with 16 neodymium magnest attached (quite small though - a mixture of circular 10x3 and rectangular 10x5x5

Seems to work but my charge battery is sooo dead (voltage circa 8.5V) taking a while.

Lots of questions, but three to start with

1. To get operation the base resistor pot is fully off (ie 0 ohms and effectively I have had to reduce the base restistor to 7.5 ohms). Clearly not quite right as the current draw is circa 400 ma

2. Magnets - I can fnd no guidelines on magnet size or strength. When I had 8 magnets there was not enough to maintain operation, but 16 works. Am I right is saying that strionger magnets would aid operation ?

3. Although I have cleaned and regreased the hum bearings there is an obvious friction. Freewheel roll time is a max of 2.5 minutes. It seems that lower friction helps (obviously). In this is there an optimum separation of the energised coil as its noticable there is a magnetic drag.

cant resist...Any views on the best transistors (or FETS). I have seen comments that 2n3055 is basic and not the best ?

many thanks
G

[Farmhand]

Hi faramog,
Sounds like your main issue could be magnets, my wheel is 27 inch with 18 magnets 40mm x 25 mm x 10 mm, ceramic is probably better, because neo's could be too strong if they are big, the spacing between the coil core and magnets is kinda dependant on the supply voltage you use, about 6-8-10 mm all work for me. It may be a good idea to get it running first with a ok battery on the charge side.

The SSG Starters Guide was a great help to me. Just google it, its a pdf, easy to download there is part one and part two.

Cheers .

Oh the friction you see when freewheeling will not be a problem once you are able to tune the Device to electro-magnetic equilibrium, I think is the term.

[blackchisel97]

Built my first SGG:
Coil is 24 & 20 swg aprrox 480 turns and steel nails as the core
25 inch Bike wheele with 16 neodymium magnest attached (quite small though - a mixture of circular 10x3 and rectangular 10x5x5

Seems to work but my charge battery is sooo dead (voltage circa 8.5V) taking a while.

Lots of questions, but three to start with

1. To get operation the base resistor pot is fully off (ie 0 ohms and effectively I have had to reduce the base restistor to 7.5 ohms). Clearly not quite right as the current draw is circa 400 ma

2. Magnets - I can fnd no guidelines on magnet size or strength. When I had 8 magnets there was not enough to maintain operation, but 16 works. Am I right is saying that strionger magnets would aid operation ?

3. Although I have cleaned and regreased the hum bearings there is an obvious friction. Freewheel roll time is a max of 2.5 minutes. It seems that lower friction helps (obviously). In this is there an optimum separation of the energised coil as its noticable there is a magnetic drag.

cant resist...Any views on the best transistors (or FETS). I have seen comments that 2n3055 is basic and not the best ?

many thanks
G

First of all, neodymium magnets are not suitable for SSG. They are too strong and will saturate iron core. 2" x 7/8" x 3/8" or 1/2" will work just fine.
Neodymium can be used with air coils, without core.

Your coil should be ok.

Base resistor should be around 500 - 600 Ohms. 1 kOhm pot will do the job. You can also connect a small "grain of wheat" bulb (50 -100mA) in series with pot and transistor base. Since the resistance of the filament increases with more current flowing through, it will help tuning. You want the bulb to barely glow not bright.

Ceramic magnets as I said earlier will work. Even round 1" craft magnets will.
Most important is equal spacing your magnets, so you have to calculate (quite easy on bicycle wheel). Don't put too many. Magnets not suppose to be closer than 1.5 -2 magnet widths from each other. 16 will do.

Aim for highest freewheel you can get. 2.5 min isn't bad. There are lubricants which will help (teflon based) but bicycle bearing are far from good. Don't worry, it will work despite that.

Experiment with coil gap as well as a "sweet spot". There may be more than one. Try to tune for highest rpm while having lowest input current at the same time. In other words - don't go for highest speed but keep an eye for both. You'll notice your wheel suddenly getting up speed while increasing pot resistance. Also keep an eye on the bulb - great help.

Best transistors for any J.Bedini stuff are MJL21194 but 3055 will work too.

I hope this helps


Vtech

[Farmhand]

With a bike wheel you may be able to space the magnets by the spoke positions to ensure even spacing like blackchisel97 says.

Thats what I did, but depending on the wheel it may not be practical, I think the wheel rim should be non magnetic.

[blackchisel97]

With a bike wheel you may be able to space the magnets by the spoke positions to ensure even spacing like blackchisel97 says.

Thats what I did, but depending on the wheel it may not be practical, I think the wheel rim should be non magnetic.

Yes! Plastic from BMS bike or similar would be ideal but aluminum will work fine. Another important thing is wheel supports. They shouldn't be made of metal. It will interfere with passing magnets. Wood or plastic is recommended.


Vtech

[faramog]

Thanks for the quick feedback. I ordered Neodiumium as that was what was recommended on some posting somewhere (not this site). Pending obtaining weaker magnets I will remove the core and re-check.

The SSG guide is useful - wish I had found it before.... Will modify and see where I get to tomorrow

Thanks

[blackchisel97]

More on SSG

There is also another thread which has alot of useful info - http://www.energeticforum.com/renewa...bedini-sg.html


Vtech

[john_g]

Can you help?

Hi

I was playing around last night with a SSG using a 3055 but I removed the pot as I suspected it had a snag and tried running the SSG. It ran be it slow, using a 12V lead acid battery. Using an oscilloscope to check the wave forms etc, I noticed that the collector voltage was 28V from collector to batt -ve, and the + lead to the power coil to the batt -ve was + 3.5 volts. To me, I stand corrected, it seemed odd, so I disconnected the leads from the batt to check the batt voltage which was 10.6 volts - then the oscilloscope probe flashed and started to smoke from the ground lead. So, is it a no no to use the oscilloscope to check battery terminal voltage (my new toy)? and any ideas about the high collector voltage?
Regards
John

[Zooty]

Most important is equal spacing your magnets, so you have to calculate (quite easy on bicycle wheel). Don't put too many. Magnets not suppose to be closer than 1.5 -2 magnet widths from each other. 16 will do.

I have to disagree with equal spacing but i agree that the magnets must be at least 1.5-2 magnets apart. The only benefit of equal spacing is the weight balancing of the wheel when it spins. They don't need to be perfectly spaced because the coil is triggered on a per magnet basis on the standard SSG setup. If the trigger coil was a separate coil then yes, the magnet alignment would be one of the most important factors.

[Farmhand]

Hi john,

so I disconnected the leads from the batt to check the batt voltage which was 10.6 volts - then the oscilloscope probe flashed and started to smoke from the ground lead. So, is it a no no to use the oscilloscope to check battery terminal voltage (my new toy)? and any ideas about the high collector voltage?

Was the SSG running when you disconnected the battery? It should be ok to use the scope probes on the battery if the scope is set correctly, I think.

IF you left the scope connected to the SSG output and disconnected the charging battery that could cause problems for the scope maybe.

I can't tell by your description which battery you mean charge or source?

It's odd that everyone missed your question it seems, but i'm sure thats all it was.

Cheers

[blackchisel97]

@John

Farmhand is right.
I hope your scope didn't suffer. Make sure you're on the right setting and use x10 probe if you have one. However, your probe could fry. 28V seems a bit high.
If you left your SSG running while disconnecting secondary or charging battery HV could damage more than just a probe. Re check transistor before letting run again.

hope this helps
Vtech

[john_g]

Thanks for reply

Farmhouse and Blackchisel97

Thanks for the reply. The batt was the source, which was disconnected from the SSG circuit at the time of probing and flash. Probe was at X10 - strange things happen.

Regards
John

[Farmhand]

Oh well that does seem strange. Is your scope ok thats the main thing! Hope so.

[blackchisel97]

Farmhouse and Blackchisel97

Thanks for the reply. The batt was the source, which was disconnected from the SSG circuit at the time of probing and flash. Probe was at X10 - strange things happen.

Regards
John

To me it sounds like your probe shorted to the ground. It did happen to me once. In such case your scope should be ok. but I would check the probe.


Vtech

[faramog]

update

Had some success (limited) and now obvious the neo's were saturating the core and nothing happened when the core was removed. I ordered some ceramics and they arrived. Put them on and wey hey ! Where I was getting unloaded spikes of circa 30v, I now got spikes somewhat over 120V. Unfortunately I burned 3 transistors before I realised that the zener protection (80V) across the Collector-Emitter was not connected properly.

Gotta get some more now !! and then we will see

G