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ron_o
Moderator



United Kingdom
1052 Posts

Posted - March 02 2013 :  16:42:35  Show Profile Send ron_o a Private Message  Reply with Quote
Ok , i will make sure its a "comfy" one , it just might be a bumpy road , lol

ron
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The_Architect
Average Member



USA
327 Posts

Posted - March 02 2013 :  16:48:31  Show Profile  Visit The_Architect's Homepage Send The_Architect a Private Message  Reply with Quote
include me in that seat saving :)

Violence is the last refuge of the incompetent
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Luciano
Average Member



213 Posts

Posted - March 07 2013 :  17:59:32  Show Profile Send Luciano a Private Message  Reply with Quote
Great information here...

As i said, i am going to get myself 2 of these:

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2 banks, 7x2,5 volts at 2600 farrad per cap
If i am correct this will give me around 371.4 farads
(I did the calc here: You must be logged in to see this link.)

with rons formula a couple of pages above i also calculated it would run my system for 50 minutes.
(if assumed consumption is 6 watts - will probably be much less.)


I want to use the 2 banks with a ssg / adams type motor/generator instead of run and charge battery.

of course it sounds great to replace the batteries with capbanks, but maybe its not as easy as it sounds.


In this particular case, there is no special loading circuit there only a couple of diodes. (the circuit is in a diagram on the page i posted above.)

I read somewhere when caps are hooked in series like this, you would need a circuit to watch the load of each cap, so one in the middle for instance would not overload.
example: You must be logged in to see this link.
they sell ciruitry to protect caps. do i need something of the kind for those banks? actually that circuit consumes in heat all the extra energy once the caps are full. there is one circuit for each cap in the bank.


or should i use a charge regulator similar to the ones used for windmills or solar panels?
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I know i should not charge the banks with more than 7x2.5 = 17.5 volts.
If I put a bridge rectifier AND a lets say 10000 microfarrad 16v cap on the ssg loading output. would that be safe? i assume that this would "kill" the high voltage spikes. (but i could be wrong of course)




The cap bank will give 17volts... my system should run on 12-14 volts.
can i somehow limit the output voltage of the caps to 12 volts easily or do I need a transformer?
a bit like a dc/dc converter i would use in a car to power a laptop or some other appliance.
(acutally i allready have a maplin dc/dc converter you can use for 12/24 volts in and switch the output to: 3,6,9 or 12v)
Would I need this or is it irrelevant?


Could i use an automatic battery swapper circuit? similar to the daftman circuit?
or would it harm the caps?

Those are the first questions i have but there surely will be others when i get the devices.

Thanks for any suggestions.

Luc

Edited by - Luciano on March 07 2013 18:03:44
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ron_o
Moderator



United Kingdom
1052 Posts

Posted - March 07 2013 :  19:26:01  Show Profile Send ron_o a Private Message  Reply with Quote
Hi Luciano

It would be wise to limit the usable voltage to 2 volts per capacitor ( restrict the charging voltage to 12 volts ) using a current limited power supply

A balancing circuit is essential

The output voltage from the caps is DC a AC transformer will not work , you could use a low loss voltage regulator ( but this wastes power or a switching regulator , again power is wasted ) If you restrict the caps to a maximum charge of 12 to 14 volts you will not have to worry about the output.

You would need to filter and smooth the output from your generator , crowbar overvoltage protection could be used to "kill" any "dangerous" voltage spikes BUT it would need resetting. An inductor / capacitor combimation would help with this

ron
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The_Architect
Average Member



USA
327 Posts

Posted - March 08 2013 :  15:34:52  Show Profile  Visit The_Architect's Homepage Send The_Architect a Private Message  Reply with Quote
ok so here is my question concerning diodes since they, as Ron_O pointed out to me, have capacitance, (and that is probably going to have something to do with the breakdown reverse voltage I am guessing)



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ok so two questions. can I increase the distance or add something to the area between the plates in an air core capacitor, and increase the voltage they can handle, and increase the size of the plates or amount of plate (or both) to increase the amount of Farards they can store before discharging?

and question two, can I use the diodes in the epoxy, and get them to maintain the combined voltage or are they still only able to handle the voltage of one of them and applying more will cause a cascade failure? (if this will work then the epoxy would be getting embedded in to a core of a heat sink to hopefully allow them to stay cooler and last longer.)

Edited by - The_Architect on March 08 2013 15:50:18
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ron_o
Moderator



United Kingdom
1052 Posts

Posted - March 08 2013 :  17:41:59  Show Profile Send ron_o a Private Message  Reply with Quote
Hi The_Architect

Question 1 :- Yes , increasing the distance between the plates will increase the working voltage . Yes again , a suitable dielectric will both increase the capacitance and increase the working voltage ( you may even be able to reduce the gap between the plates which will of course also increase the capacitance )
The quantity of charge ( per capacitor as energy ) is a function of voltage and capacitance , however a natural leakage of charge to the surrounding will occur , obviously this leakage increases with potential.

Question 2:- new working voltage = number of rectifiers x working voltage of 1 rectifier ( in your example 60,000 volts )

Epoxy resin may not be able to withstand the 60,000 volts ( may need corona dope )

The edges of your capaciror plates need to be very smooth and rounded ( polished finish if possible )

Depending upon capacitance required ( normally picofarads ) it might be possible to use a series combination of comercial high voltage caps ( again corona dope would be useful )

Not exactly sure why you want to have a variable capacitor , if its to vary voltage it's far easier to vary the input voltage to the multiplier circuit/array

Also remember that every doubling stage reduces the output current by apptox one half


Equations:-

Approx Capacitance ( pF ) = 0.2249 x area of one side of one plate / distance between plates

all measurements in inches


dielectric constants

air = 1
high voltage transformer oil approx 2.5
mica = 6
glass ( non-leaded ) 4.5 - 7 ( depends upon grade/type )
plexiglass = 4
dry paper = 2

so for example your capacitor measured 100 pF with air as the dielectric then by using mica as the dilectric the capacitance would become 600pF ,dry paper = 200 pF

ron

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The_Architect
Average Member



USA
327 Posts

Posted - March 08 2013 :  23:26:47  Show Profile  Visit The_Architect's Homepage Send The_Architect a Private Message  Reply with Quote
thanks. I will look further into that, the rounded smooth nature should be very easy, as I polish metal plate all the time for my goggles :) on the flats though, should those be mechanically smooth, like when something is lapped flat? or just a very low degree of any angles like when you take something rough and buff it with rouge? I guess I can do some testing as I have a pretty good free source for brass, bronze and copper sheet.

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ron_o
Moderator



United Kingdom
1052 Posts

Posted - March 09 2013 :  14:44:51  Show Profile Send ron_o a Private Message  Reply with Quote
As the potential on the plates increases so does the "leakage" of charge to the surrounding so smoother the better , also use circular plates ( or as circular as possible ) no sharp points etc

ron
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The_Architect
Average Member



USA
327 Posts

Posted - March 10 2013 :  04:43:02  Show Profile  Visit The_Architect's Homepage Send The_Architect a Private Message  Reply with Quote
ok I will :) I will post some pics some where on the build so others hopefully can use the info to make their own builds a little better either by following my successes or by avoiding any of my failures :)

Violence is the last refuge of the incompetent
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oh and looking at MG chemical's site, it seems that xylene or xylol is used for thinning the corona dope they sell currently, Reason I find this useful is that I have plenty of it around, and plan on thinning the dope down so I can place my cap plates on a computer fan and spin them down the way you see Jeri Ellesworth doing here at time point 2:45
You must be logged in to see this link. to make sure I have a uniform coating per layer, so I can more effectively control this build up :)

Edited by - The_Architect on March 10 2013 05:02:07
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ron_o
Moderator



United Kingdom
1052 Posts

Posted - March 10 2013 :  17:40:35  Show Profile Send ron_o a Private Message  Reply with Quote
Hi Architect

Yes , you will obtain a very uniform coating using the "spinning wheel" application method.

If you thin the dope down the ideal viscosity for application will be found when a steel ruler dipped into the solution and quickly removed and held at an angle of 45 degree allows a constant single flow off ( ie no curtaining ).
It's basically a Newtonian liquid so the temperature is unimportant with respect to this visosity check.

Homemade dope :- i found an article on the net some time ago in which an insulating dope was made by dissolving polystryene foam in Xylene and allowing it to stand for a while to allow the Titanium Dioxide ( white pigment , used to colour foam ) to phase out.
I did of course have to give it a try and found it to work very well , you need to use the low density type foam , the high density ( hard / tough ) grade seems to almost resist the xylene ( so i tried acetone , acetone/xylene , butyl acetate all "poor" , however i found that carbon tetrachloride and methylene chloride were excellent solvents but the speed at which these solvents "flash off" / evaporate made it very difficult to obtain a uniform coating )

I still have about a gallon of the xylene based one left !

BTY because it "dries" by solvent evaporation it also redissolves in xylene which can either be considered a good or bad thing

ron
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The_Architect
Average Member



USA
327 Posts

Posted - March 10 2013 :  21:22:42  Show Profile  Visit The_Architect's Homepage Send The_Architect a Private Message  Reply with Quote
very interesting. are you sure the "hard" foam was polystyrene based? I have seen a LOT that were based on urethane and polyethylene, that looked almost identical to styrofoam. I love the "make it at home approach though :) I will have to look into this, I am guessing that any styrene product and not just foam would work too, as I can obtain plenty of clear styrene sheet to dissolve in xylene :)

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The_Architect
Average Member



USA
327 Posts

Posted - March 11 2013 :  17:20:21  Show Profile  Visit The_Architect's Homepage Send The_Architect a Private Message  Reply with Quote
something else I was wondering, is how effective using oxide layers to produce dielectric effects would be. I know that the reason metals like titanium can be colored to specific colors is due to the oxide build up is very specific based on the amount of voltage applied, once an area is built up to the max the voltage can push through, the electrons seek a lower resistance area that has thinner oxide coating to pass through, until the whole item is evenly coated. I have some titanium CP2 grade sheet, that was nearly as cheap as the aluminum I get for the same thickness, so if this is something worthy of looking into I may have to hit up the guy I got it from for more of it :)

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ron_o
Moderator



United Kingdom
1052 Posts

Posted - March 13 2013 :  16:18:25  Show Profile Send ron_o a Private Message  Reply with Quote
Ti02 has some very intresting properties , for example it can be used to make a solar cell that produces electricity

Thats a good point about the foam ( to be honest it never dawned on me at the time ) . I had managed to "obtain" about a 45 gallon barrel of clean but broken foam pieces ( the despatch department at work had been saving them for me ) so at the time i guess it was dissolve / won't dissolve ( some of the pieces that would not dissolve got "hit" with stronger solvents )

I guess the oxide on the titanium sheet could be intresting but i dont know the dielectric strength

ron
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Luciano
Average Member



213 Posts

Posted - March 15 2013 :  17:09:31  Show Profile Send Luciano a Private Message  Reply with Quote
Thanks for your suggestions ron.
what I will do to get more familiar with supercaps, i will get a 7x 10 farad bank, (the 10 farad are about 1$) and once i get it working, only then i will get the big one, 7x2600

(Sorry for late reply i was out of town)
Luc


quote:
Originally posted by ron_o

Hi Luciano

It would be wise to limit the usable voltage to 2 volts per capacitor ( restrict the charging voltage to 12 volts ) using a current limited power supply

A balancing circuit is essential

The output voltage from the caps is DC a AC transformer will not work , you could use a low loss voltage regulator ( but this wastes power or a switching regulator , again power is wasted ) If you restrict the caps to a maximum charge of 12 to 14 volts you will not have to worry about the output.

You would need to filter and smooth the output from your generator , crowbar overvoltage protection could be used to "kill" any "dangerous" voltage spikes BUT it would need resetting. An inductor / capacitor combimation would help with this

ron


Edited by - Luciano on March 15 2013 17:10:39
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ron_o
Moderator



United Kingdom
1052 Posts

Posted - March 17 2013 :  18:58:54  Show Profile Send ron_o a Private Message  Reply with Quote
Hi Luc

Thats probally the best way , even a 10 Farad bank can pack quite a "punch". Do you still intend to run a window motor with it ?

ron
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Luciano
Average Member



213 Posts

Posted - March 18 2013 :  01:35:48  Show Profile Send Luciano a Private Message  Reply with Quote
Yes but its not really a window motor. its something between adams and muller.
the idea was to use something like a battery switcher to automatically switch between run and charge bank. and see for how long i can get it to run.

But my main problem for the moment are the run coils. I've been fighting with them for days.
winding and rewinding. and... getting very strange effects. Like with 6 coils hooked up and only 2 positioned i get 1300 rpm with 400 mA draw (the other 4 are just sitting there and pulsing into nowhere). But when i start positioning the other 4 coils the rpm and draw go down. (i would have expected at least the rpm to go up) so I end up with 800 rpm and 45 mA draw.
(I will make a video and post it under "pulse motors" as soon as I have finished rewinding the new series of 6 coils with a different core diameter)
Luc
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ron_o
Moderator



United Kingdom
1052 Posts

Posted - March 18 2013 :  16:12:43  Show Profile Send ron_o a Private Message  Reply with Quote
Hi Luc

Magnetic fields between the coil can interact , this can give "strange" effects also have you got your coils phased correctly?

I will wait for you video.

ron
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flanabee
New Member



USA
9 Posts

Posted - March 19 2013 :  13:13:54  Show Profile Send flanabee a Private Message  Reply with Quote
Found a supplier of air caps in the USA. 'orenelliotproducts.com' They make custom units too!

Edited by - flanabee on March 19 2013 13:14:56
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ron_o
Moderator



United Kingdom
1052 Posts

Posted - March 20 2013 :  18:09:59  Show Profile Send ron_o a Private Message  Reply with Quote
Capacitors , a practical guide ( in several postings # 9 )

Some time ago the subject of voltage balancing on series connected capacitor was briefly mentioned without any equation or example , so its time to put things right !

Series Capacitors : Voltage Balancing

All capacitors have a tolerance in their stated capacitance , the worst type being electrolytic capacitors where a tolerance of + / - 20% is not uncommon.

When capacitors are connected in series and a voltage is applied the capacitors act as voltage dividers , now in an ideal world all capacitors would have a capacitance that was exactly what was stated on the label , this however is far from true and this variation in capacitance results in an inbalance in the voltage across each of the series connected capacitors.

If we consider the "worst case" example lets say that capacitor "A" is + 20% overvalue and capacitor "B" is - 20% undervalue. Both capacitors have a working voltage of 450 volts and in this example the applied voltage ( across the series connected caps ) is 900 volts

Equation:-

Voltage across capacitor = Voltage applied x Maximum tolerance / ( Maximum tolerance + ( n-1 )) x Minimum tolerance

where n = number of series connected capacitors

Example :-

voltage across capacitor = 900 x 1.2 / ( 1.2 + ( 2 - 1 )) x 0.8

voltage across capacitor = 1080 / 2.2 x 0.8 = 511 volts

So the capacitor with the lower tolerance ( "B" ) has 511 volts across it whilst capacitor "A" has ( 900 - 511 ) 389 volts across it.

Obviously this is not safe and breaknown in capacitor "B" will occur and hence the voltage needs to be balanced to prevent this happening ( see part 10 )

ron



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Luciano
Average Member



213 Posts

Posted - March 22 2013 :  00:54:12  Show Profile Send Luciano a Private Message  Reply with Quote
so if i understand correctly, we should always choose capacitors more than 20% over the expected voltage?
I am speaking of stand alone caps.
Example:
the cap at the "entrance" of my circuit is 100yF - 25volts.
I am running at 12 volts (fully charged battery can output up to 14) so thats ok.

But if i do tests with 24 volts.. then i should switch to a 35 or 40 volts capacitor..
I understand.
Now my question: is there any drawback for my circuit (when running at 12 volts only) if i have lets say a 100yF - 40 volts cap instead of the 25 volts one?

Luc

Edited by - Luciano on March 22 2013 00:54:50
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ron_o
Moderator



United Kingdom
1052 Posts

Posted - March 22 2013 :  18:10:10  Show Profile Send ron_o a Private Message  Reply with Quote
Hi Luciano

The choice of a capacitors working/rated voltage depends upon the application. It is reasonable to assume that if as in your example above where a maximum of 14 volts exists that a capacitor with a working voltage of 25 volts is a very safe choice.
Likewise in a circuit where a maximum of 24 volts is present a capacitor with a working voltage of 35 or 40 volts is ok
to use.

Now to your question .... the answer is dependant upon the quality of the capacitor , all electrolytic capacitors require a certain voltage across them to maintain the oxide film which forms the dielectric between the plates that form the capacitor ( this is one of the reasons why capacitors have voltage "ranges" ). A good quality capacitor would normally be ok BUT the 25 volt option would be the obvious choice. A cheap capacitor might not be able to maintain the dielectric and the uF value will be less.

ron

Edited by - ron_o on March 22 2013 18:30:16
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ron_o
Moderator



United Kingdom
1052 Posts

Posted - March 22 2013 :  18:29:09  Show Profile Send ron_o a Private Message  Reply with Quote
Carrying on from a question raised by Luciano regarding capacitor working voltage.

Lets look at a transformer / bridge rectifier / capacitor combination

Lets say the transformer is rated at 24 volts AC , what voltage capacitor should be used ?

All transformers show a variation in output voltage as the load is increased or removed ( this is known as "regulation")
depending upon the "quality" of the transformer this can range from a couple of percent to 30 % ( or even more ! )
In the following example we will assume 20%

So maximum AC output = 24 x 1.2 = 28.8 volts

voltage "gain" from bridge rectifier = 28.2 x square root of 2 = 40.73 volts

If we also take into account possible variations in mains input voltage causing an additional increase in output voltage the nearest standard working range capacitor is 63 volts.

As a "rough" guide to required value of capacitance , work on an absolute minimum value of 1 uF per milliamp of required output current ( i personally work on approx 4.7 uF per milliamp of output current )

ron

Edited by - ron_o on March 22 2013 18:31:24
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Luciano
Average Member



213 Posts

Posted - April 12 2013 :  01:18:31  Show Profile Send Luciano a Private Message  Reply with Quote
thanx ron for those explanations. As I still have a couple of 40v 47000uF caps at home, that would mean that i could go up to 10 amps (if I understood your calculations correctly and using your specs of 4.7 uF per mA).

If I may I would like to ask another question, as I am just bringing some ideas to paper...

Its probably a very trivial question,
but i just do not know if i am thinking the right way.

Can i dump multiple capacitors into one single cap?

An easy example of what i mean (as english is not my mother tongue I sometimes formulate my questions in a strange manner):

Lets say I have 2 pickup coils, each one produces lets say 10 volts (to make calculations easy)

Each one is connected to a cap. ( one cap each)

Now using blocking diodes, can I dump both into a third cap?

The idea behind it is that i would like to try to hook up each pickup coil to a voltage comparator cap dump circuit. when the coils cap reaches a certain voltage, under the caps specs, it would dump the contents into the big cap that is connected to the load.
thats the principle. But with multiple coils it could be that 2 caps fire at the same time. So my question, would it be sufficient to add some blocking diodes to make sure the current can only flow into the third cap, OR is there more to it I would have to look into??

I have seen such circuits but most of them fire sequencially, or if a voltage comparator is used, its only a single cap firing into a battery, not many caps firing into a single one.
So do I have to watch for something special?
Or is the idea not very smart from the beginning?

thanks for any advice

Luc

Edited by - Luciano on April 12 2013 01:36:18
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ron_o
Moderator



United Kingdom
1052 Posts

Posted - April 13 2013 :  16:19:06  Show Profile Send ron_o a Private Message  Reply with Quote
Hi Luc

The uF per ma is normally used to ensure sufficient smoothing ( to reduce ripple ) in power supplies. Capacitors do have a maximum ripple value , this is obtained via manufactures data sheets.

My previous posting show calculation for amount of stored energy.

The bank of caps discharging into a single cap......... yes it can be done but here's the problem , electricity ( like all other forms of energy ) cannot flow upwards. So lets assume that the first cap is charged to 12 volts , for the second cap to discharge it must be at a voltage that is greater than 12 volts ( lets say its at 14 volts ) so the second cap can only discharge 2 volts BUT REMEMBER the first caps terminal voltage is also increasing ( due to the flow of charge ) so that original 2 volts difference might only now be say 1.2 volts. As the process continues the same happens over and over again.

You could use voltage comparators and blocking diodes but its still the same situation exists

Also take into account the time constant effect of the capacitor / load ( approx 63 % discharge in 1 time constant but it takes a further 4 time constant periods to elaspe to reach 99% discharge )

Can you afford this time delay , since it is directly related to rotor rpm ?

ron

Edited by - ron_o on April 13 2013 17:44:09
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Luciano
Average Member



213 Posts

Posted - April 14 2013 :  02:02:58  Show Profile Send Luciano a Private Message  Reply with Quote
Thank you ron
I had forgotten all about the time constants and the fact that the discharge will depend on the "charging status" of the cap being charged.

I think it actually depends on the rpm, the caps dimensioning and on the output of the coils.
Also the situation is probably different if there is a load or not as it will be draining the final cap.

As an alternative i have been also thinking of sequential dumps.
(1 little south magnet on the rotor that is all north)
each coil having a hall sensor triggering a transistor or mosfet that dumps the cap once per rpm.

But either method always brings me to the same question. To formulate it in a simplistic way:

How do i "group" (hookup) the output coming from the different coils/caps so i can run a single load?

My idea behind the cap dump is that the rotor and the pickup coils will not be influenced by the load (lenz etc..) as they will only see the cap loading behind the BR.
if the load is too big for the output (example a 60watt car headlight on a tiny machine that only produces lets say 2 watts) it will just not light up, but the motor should (at least in my mind - lol -) continue turning as if was only charging the caps.

I will get the parts for my voltage comparator next week, and conduct some low level experiments.
any ideas on how to hook up the different outputs are very welcome.

Luc
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ron_o
Moderator



United Kingdom
1052 Posts

Posted - April 14 2013 :  11:57:20  Show Profile Send ron_o a Private Message  Reply with Quote
Hi Luciano

I think i know what you are trying to achieve and both methods that you have already stated ( sequential cap "dumping" and a voltage comparator control ) will work ( a blocking diode per capacitor will also be required ).

The rpm , diameter of the rotor , active width/diameter of the magnet and the number of magnets will directly effect the size/value of both inductor and capacitor ( this is to allow sufficient time for the inductor to charge and then discharge into the capacitor ). I have worked out a timing equation that will give you some idea as to possible inductor/capacitor time constants


"FLY-BY" CALCULATIONS ( for sensor / coil on - off times )

Total off time = 60 x ( rotor diameter x Pi - ( 1 magnet diameter x number of magnets)) / ( rpm x rotor dia x Pi )

Total on time = 60 x diameter of 1 magnet x number of magnets / rpm x rotor diameter x Pi

Times are in seconds

Note.... magnets in the above equations are mounted equidistant about the circumference of the rotor

Note.... rotor diameter:- this is to include the thickness of the magnets if they are mounted/attached to the edge of the rotor

Percentage Duty Cycle( on ) = ( Total on time / ( total on time + total off time ) ) x 100

Pulse frequency ( Hertz ) = rpm x number of magnets / 60

Time for a magnet to pass a fixed stationary point ( i.e a Hall sensor )

Time (pass by ) = 60 x dia of 1 magnet / rpm x roror diameter x Pi

Also remember to include the switching devices internal resistance + the coils own resistance into the time constant calculation

A "slightly" off topic reply but hopefully it will be of use to you

ron
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Luciano
Average Member



213 Posts

Posted - April 17 2013 :  15:56:51  Show Profile Send Luciano a Private Message  Reply with Quote
Wow! Now if with that i dont succeed i should stop experimenting...
thats more help i ever expected.
Thanks a bunch.
This is really great!
Luc
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ron_o
Moderator



United Kingdom
1052 Posts

Posted - April 17 2013 :  16:37:06  Show Profile Send ron_o a Private Message  Reply with Quote
Hi Luciano

Glad it's of use to you , but please never give up / stop experimenting.

All the best

ron
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olddawgsrule
Advanced Member



USA
1434 Posts

Posted - September 17 2013 :  17:52:35  Show Profile  Visit olddawgsrule's Homepage Send olddawgsrule a Private Message  Reply with Quote
Ron, you answered Screamin' with the statement of being careful not to build a capacitor with his collection plates.
(You must be logged in to see this link.)

You gave me a unique perspective of capacitors and what they're potential is, yet I never understood how to build one.

It seems Screamin' may have done that unintentionally, if you hadn't intervened.

One more reason I am very happy you took this new posting!

Talk to me (us) about this a bit...
Building layers of recievers
With a singluar ground
Creates a capacitor
If placed accordingly
Which is once again like a battery...
But where does it store???
Can it store??

Far too many questions..
Far too many thoughts..




Old in age, not in mind, so
'Teach me something new'!

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ron_o
Moderator



United Kingdom
1052 Posts

Posted - September 18 2013 :  18:48:18  Show Profile Send ron_o a Private Message  Reply with Quote
Hi ODR

A capacitor consists of 2 or more conducting layers seperated by an insulator
The insulating material ( dielectric ) is actually where the charge is held.... ( yes air can hold a charge )

equation for capacitor plate size etc in an earlier posting

So back to Vern's project ( if you remember i stated to use one common earth point )

The gap between the metal roof tile and the receiving plate if small could form a capacitor
( experiments that Vern has carried out in the past have detected radio waves of low frequency so it was important to remind Vern ) and the insulated downlead could form a tuned circuit which would have a resonant frequency which could "bleed" off the energy required to grow the plants

I know i probally have now generated more questions but just ask them and we will work our way through them

ron
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olddawgsrule
Advanced Member



USA
1434 Posts

Posted - September 19 2013 :  16:19:43  Show Profile  Visit olddawgsrule's Homepage Send olddawgsrule a Private Message  Reply with Quote
That answers quite a few of the unasked.

I've always know not to have collector plates too close (mainly to avoid an arc), yet never thought of the possiblity of creating, an air capacitor (?).
Hadn't realized it could happen..
Didn't know it existed..

The immediate questions heads towards the Solar Panels.
Are they insulated/isolated enough not to create a form of this?






Old in age, not in mind, so
'Teach me something new'!

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ron_o
Moderator



United Kingdom
1052 Posts

Posted - September 19 2013 :  17:54:17  Show Profile Send ron_o a Private Message  Reply with Quote
Hi ODR

I honestly don't think you need to worry about that one. If any charge was ever generated it would bleed off naturally to earth via your connected equipment.

ron
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Luciano
Average Member



213 Posts

Posted - October 27 2013 :  09:51:35  Show Profile Send Luciano a Private Message  Reply with Quote
Hi ron,
need your wisdom again..
Just got myself some supercaps 100F .. (were rel. cheap so i couldnt resist)
putting them in a bank.. and using the balancing circuit lasersaber presented on his site..
You must be logged in to see this link.
just diodes and leds but it seems to work nicely.

Before i start building the "pack" i have 2 questions
I got some leds that have the same specs (typical voltage, amp draw etc) than those he uses.. but only 40 mcandelar instead of 16000 ... hope thats not critial.

But supposing the pack works, my question is.. will i be able to charge it via the bedini output of my motor?
after bridge rectifier and normal cap?
it says in the notice: pulse charging is not recomended. but does that only apply to non rectified current coming out of the bedini? (of course i will not overcharge them..)

ah yes and final question: to empty the supercap bank.. can you shorten it without damaging it?
when i pack normal strong caps away.. i usually shorten them with a screw driver so nothing will happen if i come to grabbing them quickly one day.

I like the idea of running my motor on supercaps.. its a 22 volts bank (like in the video).. and I think some good experiments can be done...

Luc

Edited by - Luciano on October 27 2013 09:54:40
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ron_o
Moderator



United Kingdom
1052 Posts

Posted - October 27 2013 :  20:17:30  Show Profile Send ron_o a Private Message  Reply with Quote
Hi Luc

The difference in light level output will not be a problem ( its only the electrical specs that need to be similar )

The output from the Bedini , once rectified ans smoothed should be fine ( smoothing cap should be at least one microfarad per milliampre of charge current to your supercap bank )

Capacitors should NEVER BE DISCHARGED BY DIRECTLY SHORTING THE TERMINALS , A SUITABLE POWER RESISTOR SHOULD BE USED.

BTW spot welding machines that use capacitor discharge do so through a step down transformer so the inductive nature of the windings restrict inrush ( discharge current from cap )current . Also this type of capacitor has a special construction / design

ron
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Luciano
Average Member



213 Posts

Posted - October 27 2013 :  23:57:10  Show Profile Send Luciano a Private Message  Reply with Quote
thank you for your reply... so I will start building..
as for the power resistor..what would be a suitable choice?
just thinking of building a little discharge box... the first thing that would come into my mind is hooking up two 60 watt car bulbs in series... they should drain those caps quite quickly.

as to shorting terminals, there is an experiment (similar to coil shorting) i successfully reproduced. (ok, they were only 10 microFarad.)
but it was quite impressive. hooked up to a 9 volt battery, they were at close to 50 volts after shorting..
here is the experiment realized by whoopy..

You must be logged in to see this link.

I promise i will never do it with the supercap bank!

Luc
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olddawgsrule
Advanced Member



USA
1434 Posts

Posted - October 28 2016 :  17:42:08  Show Profile  Visit olddawgsrule's Homepage Send olddawgsrule a Private Message  Reply with Quote


I have this love of capacitors and always wish to learn more.
Why then do we rely on batteries, when capacitors can do the same?
As the costs of batteries increases, and the cost of capacitors decreases, I wonder if we should be changing over?

With that said, I do understand the capability/draw difference between an AC/DC capacitor.
And given the use of an DC capacitor, how much difference is there really?



Old in age, not in mind, so
'Teach me something new'!

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49er
Administrator



USA
4442 Posts

Posted - October 29 2016 :  11:09:01  Show Profile Send 49er a Private Message  Reply with Quote
Hi ODR

I have seen a cap bank to start a car and it is as big as a car battery but that is all you could do, you can't watch tv for 4 hrs on that same charge. LOL

Doug
The sky is not the limit...There are footprints on the MOON.
Your only as DUMB as where your standing.
No matter where you go there you are.
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SKYPE doug.bennett49er
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ron_o
Moderator



United Kingdom
1052 Posts

Posted - November 04 2016 :  17:35:05  Show Profile Send ron_o a Private Message  Reply with Quote
Hi ODR
The problem with capacitors is ( at the moment ) is the the amount of charge stored
per unit volume.
Batteries such as lithum iron offer energy storage capacities many times greater than our
best supercaps , but i'm sure that this will not always be the case
Secondary batteries have their own problems .... Time to charge being the most
serious...it's a chemical reaction and is thus limited by reaction rates
capacitors do not suffer from this "problem

ron
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