How much juice to zap cobalts?

[Overdrive]

Hi, I'm in the process of redesigning/improving my Capacitive Discharge mag zapper. My question is does any one know how much voltage and capacitance (uF/mF) is really needed to do cobalts? Some of the manufacturers / reconditioners should have some knowledge of what it takes. Thanks in advance!

Best Regards

Overdrive

[eap9]

Can I use my ceramic magnet zapper for cobalt magnets?

[Foamy]

You're just not going to get any satisfaction with a homebuilt unit.
It's just better sending the motor to the people that have cobalt zappers,the cost is minimal.
This is a zapper (www.maginst.com/specifications/942A_Magnet_Charger.htm) similar to the one at Sonic Products (www.sonic-products.com),although I'm sure most everyone has one similar.
BTW they cost about $15K.
That's a lot of rezapping!

[Paul Ciccarello]

I could be wrong but 400 volts rings a bell.

Paul

[Overdrive]

Eap: Most likely not, I've surmised you need a much higher energy pulse to zap cobalts (which is why I'm trying to find out how high I have to go).

Foamy: Thanks for the input! However, I still think I may be able to get to the level needed to do 'em. While I claim no "working" knowledge in designing industrial CD zappers. My background in electronics has provided me the means to develope my current 80,000 uF(80 mF) 150vdc 210 Amp (32,000 watt) 5uSEC pulse CD zapper. I also acknowledge even that is "not enough". Which is why I'm posing this question. Once I get a feeling of what's needed, Then I'll figure out if I can afford the appropriate level of capacitance to do the job.

Paul: 400 Volts? Hmmm...Are you sure thats all? Does your memory remember anything about how much capacitance they were talking about? If it's not to much I *may* acually be able afford it.

Once again thanks in advance for any and all input on this.

Best Regards

Overdrive

[Monty @ B.O.W.]

Overdrive,
I've seen the zapper at sonic that Foamy refers to, and it discharges at approx. 2600 volts according to the meter mounted on the front. From the sound it makes, there's a healthy contactor in there!

More important than the voltage and capacitance, I believe, is making sure that losses due to inductance are limited. This means that the typical large coils wound around 2" diameter steel cores - standard fare on Trik Trax units, or my own B.O.W. zappers - just won't work because it takes too long for the voltage level to come up in the coils. The caps are discharged without ever getting to the necessary flux density. The Sonic zapper, and others I've had described to me (Alpha, Koford, Slick7) are all 'air coil' units. The can/magnet assy. is placed inside a coil that then recieves all the big power. The only inductive item in the package is the can itself.

Since all these machines are of large dimension (a cubic yard or more) I was surprised when informed that Mid Atlantic area racer Ted Backo has constructed one of breadbox size, rather more the size of my own ceramic-only machines. It was supposedly quite expensive, and I have no idea exactly how it works. I was assured, however that it DID work! Maybe someone from that area can add some info.

[Overdrive]

Monty, Hmmm...Very interesting. So far from what I've been able to gather, The CD units over 400 volts acually use a solid state switch (Relay / Contactor) call a Silicone Controlled Rectifier ( Beem me up Scotty! ) for Safety Reasons. The noise ( I hear a lower decibel version in my zapper, It sounds sorta like a "Thunk") you hear might be the rapid energy pulse smashing into the coils and the coils reacting to it ( rapid energy pulses and inductance do not really like each other). The Air Core concept is very interesting. Now that you mention it, Back in my days of speaker design I learned ( and forgot ) Iron Core inductors were known to saturate at a much lower power level and also having a much higher inductance for the same number of turns of wire. Have / Can you (or anybody else)get any more info on turns / demensions of the air cores? As for the size, I still am hopefull that the finished design will about the size of 2 breadboxs. I've gathered that industrial units are large because they can be optioned in for large level of capacitance 20,000-80,000 uF (20-80mF). Those kind of levels will require several "banks" of huge capacators, If we are talking above 800 volts. If we are talking 800 volts or under, I think I could pack 20,000 uF into a breadbox sized case. That link Foamy gave was 2600 volts at under 1,000uF, Which should also fit in a breadbox. Once again any and all input is VERY appreciated!

Best Regards

Dave Ronsky

[Monty @ B.O.W.]

Overdrive,
I DO use Selenium controled rectifiers (SCR's) to switch the capacitors in my zappers - which are definitely ceramic only! I use 40,000 mfd in my circuit. Thats mfd - 1/1,000,000 of a Farad. Lets ignore ufd as being negligible. My total, then, is .04 Farads @ approx.120 volts. The actual voltage available by rectifying common household AC is almost 160 V, but it will take almost forever to actually charge the capacitors that high. I use a neon lamp to indicate when the caps are charged enough to use. Thats approx. 110 volts.

The problem with an SCR is that you just won't find one rated at over 1,000 volts - and like I said, the commercial cobalt zappers fire at over 2500 volts.

The actual coil, incidently, is ridiculously simple - 20 or so turns of what looks like 8 guage wire, a single layer. The coil is shaped to fit over a typical motor storage box, which is what the Sonic guys were using to hold the can assy. The box had a milled piece of delrin inside that closely held a typical cobalt can so that it couldn't twist in the field. The field propogates parrallel to the center axis of the coil via the 'right hand rule' for purposes of calculating polarity.

For what its worth, since 450 volt capacitors were the largest I could find, I once tried to do a machine with an air coil, 360 volt charge, and 40,000 mfd. It blew a lot of SCR's, and zapped ceramics just fine but still didn't touch Samarium-Cobalt. Good luck!

[Overdrive]

Monty, Thanks for the further details!!! While I have never heard SCR's being called Selenium Controled Rectifiers, I've always heard them as Silicone Controled Rectifiers( At least that's what Iinternational Rectifier and ST Micro call's 'em). I also have to say that at the age of 42, CRS is starting to get a firm grip on me <GRIN>. I did refer back to my electronics reference books and they indicate term "micro" having a abbreviation of "u" is represented as .0000001 and "milli" having a abbreviation of "m" is represented as .001

So far my CD setup is 80,000 microfarad and could fit into a breadbox, It's 4 big caps that are about 8" high by 4" in diameter. Plus my charging circut. Speaking of my household current charging circut it can go from 110 to 150 in about another 35 or so seconds. I use a big a$$ 25 ohm resister to limit power to around 525 watts going into the caps, and my total charge time is about 1 minute.

Yes, I agree SCR's are generally 1kv or below ( However, Digikey lists SCR's to 4.5kv on a $pecial order ba$is) Personally, Going over 1kv is scaring the heck out me( I keep on reading DEATH and LETHAL on the warning labels of over 1kv parts). Plus I have no "working" experiance above 1kv. I'm thinking of making my attempt in the 600-900 volt range. I relize there is still a lot of deadly juice at that level. But at least the proper rated wire insulation can be had easily. Also, Oerstead Technologies sez thier 800 volt 80mf CD is good enough to do cobalts, And I think they are talking about much larger SMCo magnets than we are using.

WOW, 20 turns around a delrin milled holder really IS simple! However EVERYTHING I ever read about high flux density magnetizing fixtures POO POO'ED having ANY air gap between the iron fixture and the magnet. Unfortunatly, I have ZERO experiance with magnetic saturation of iron/steel, So I don't know if maybe it could act as a hinderance at these levels. The fact that you went to 360 volts with no success, To say the least is causing me some concern. Alas, I'm still looking for as much info as I can aquire, before making my attempt. I will share my findings ( good or bad ) when I'm finished. If you or anyone else has any other thoughts on this subject, Please accept my thanks for your input!!

Best Regards

Overdrive

P.S. I DID find a few things out about going over 1kv:
1. The transformers that power NEON signs operate in the 2000-15000 volt range. Their current output is quite low however, So the charge time would be quite long ( But for home use...who cares). Also I've seen them on eBay for around $20.

2. High voltage caps are off the richter scale when bought new, However Laser and Tesla coil hobbyist have created a secondary used market for these items and you can buy them for pennies on the dollar via eBay or off the net.

3. Everyone mentions DEATH, DEADLY or LETHAL when discussing these type of items, So far it has been enough to scare me away ( even if I am a "Speed Crazed Moron" Slot Racer ) <GRIN>

[Foamy]

If you found this already,oh well,if not this may help...
oersted.com/magnetizing.PDF
enjoy...

[Overdrive]

Foamy, Yep, I've poured over that probably a half a dozen times so far. Some of the formulas are just too deep for my CRS brain, The circut schematics were helpfull though! If anybody finds any more jewels like this one, Let me know.....

-Overdrive

[Overdrive]

Monty, There is a surplus electronics store here in cleveland, I went there to see if the had any parts I could use. While I was rumaging through the racks of caps I noticed some were marked with "uf" and other manufacturers were marked with "mfd". It turns out they in fact BOTH mean microfarad. I guess each manufacturer makes their own choice as to how it's marked. I just thought you'd like to know......

Best Regards

Overdrive

[Monty @ B.O.W.]

My bad! the proper abbreviation for pico-farad is u.u.f, but I rarely see u.f. used instead of m.f.d. Mmfd (micro-microfarad) is the same as picofarad.

[RickB]

Ronski, I have a working cobalt zapper in the back room and building one for a racer now. 400 volts, 800 volts, 2400 volts, will kill ya dead, pick your poison?

And yes TRI-STATE RACER Ted Backo has several units out there and they work great. They are a work of art.

Man , it's simple, Ohms Law. Do the math, you can zap at whatever voltage you want just make the other parts fill in the gap. And don't forget as you stack up the caps, you also reduce the capactitance, seeeee, double edged sword. SO I would guess your 80000 microfarads are really about 8000, and you could probably zap at 8000 or you could zap at 375 volts, this is possible.....................

Have fun, don't get hurt!

[RickB]

You might find intersting, I had a lexan top on my zapper and it shattered it from the thunk!..............

[Overdrive]

Rick, Hey thanks for the info! BTW, It's Ronsky not Ronski. Yep, I know about caps in series cuts the value in half and caps in parrallel doubles the value. What I have is a true 80,000uf via a series / parrallel arangment. Unfortunatly it's only at 150 volts. How have you set up yours ( what voltage and capacitance )? I just picked up a set of four 7200uf 500 volt caps that I'll arange in a series/parrallel arangment and a step-up transformer that will output a tad under 900 volts. That's about as much as I care to spend on this experment. Acording to my calculations I should be able to produce .005 second pulse that should peak around 1.1 million watts. The idea of that much power is just scaring the crap out of me. And now you tell me your "Thunks" fractured your lexan cover? Assuming it wasn't coming in contact with the fixture...Why YES I'm much calmer now! <GRIN> How did you arange your coil? Is it metal core or air core? Should I call you for the details? Also you got any glue races going on this summer? Let me know....

Best Regards

Overdrive

[Dan P]

And the story in the family goes something like "He had a million buried somewhere, too bad he got hit by that car and never told anybody where it was"................

I've been reading with great interest about what it takes to zap a cobalt magnet, and it occurred to me that if I exume my uncle's body, you guys could probably wrap him in a coil of 8 gauge wire and zap him back to life.............

(If you think you could pull it off, I'll split the million with ya!:))

[Overdrive]

Ummm......NO! But I bet we could make a nice bon-fire out of him though! <GRIN>


-Overdrive

[Slapshot]

Not the greatest of scan's but here's a rough diagram of how to update a standard older Zapper to a "Caps Zapper". Very crude drawing. I do not remember who gave this to me back in the late seventies but maybe it will help someone. If any one has a updated version feel free to post it.

See attachment in next thread below.
Hope these show the darn attach file option isn't working. If not see below I will try to get it to function another day.

Raymond

[Overdrive]

Slapshot, Those attachments didn't come through. They link to a password screen. Could you E-mail them to altware@yahoo.com ? Thanks in advance!

Best Regards

Overdrive

[Slapshot]

Still trying attach file option to work.

[Slapshot]

Hate this attach file feature.Info part.

[Overdrive]

Slapshot: Thanks for the scans. I'm sure they had to pay a pretty penny back then for 15 1000uf 200v caps (caps didn't become "somewhat" cheaper untill the 80's)

Everyone: Well, the only thing new that i can say is I ran a "dry" test of 2 of the caps wired in series. I pumped 935 volts into them, I was so scared I used a plastic 12" ruler to flip the switch! Then I heard what sounded like a small fire cracker ( kinda like an old lady finger) go off in my basement. The wife wanted to know "WHAT THE &*%$@! ARE YOU DOING DOWN THERE!". Actually instead of hearing a "thunk", I heard what was more like a "whack" or maybe a "crack". Anyway it was enough to make me rethink my position of releasing 1.1 million watts in .005 seconds. I'm going to start searching for perhaps a safer way.

Monty: That coil you looked at, Was it round or square? Did it have a form that it was wound on? How did they contain the can holding fixture inside the core? How long were the leads coming from the cabinet? About what gauge? From what little I've been able to read, Air core magnetic oreintation is axially down the center line of the core. Is that what you saw? Let me know....

That's it for now...

Best Regards

Overdrive

P.S. For those interested, "Magnetic Rail Gun" hobbyists are researching along the same lines as what I've been doing and I've found a lot of good stuff just by doing a search using that term ( There is some dude down in south america that has a HUGE bank of caps and is releasing 5-10 times the power of what I'm doing, He appears to have really deep pockets).

[Slapshot]

Overdrive you have now experienced what the most brilliant inventors Nikola Telsa worked all his life on. The man that invented the Telsa coil. Interesting reading he had a lot to do with high energy electronics of today. Very profound inventions. You'd find it interesting to read up on him. Thousands of web sites devoted to his work if you do a Web search on his name. Was rumored to invent a machine that emmitted a high energy charge that he was able to aim crudely the charge over great distance. Of which one of his experiments accidentally demolished a village in Russia from his lab in the States back in the late 1920's. Shades of Star Wars. He probably used a ruler too to switch things on also.
Raymond

[Slapshot]

Zapper gone wild!!!!

[Slapshot]

Another Zapper gone wild!!!!

[Overdrive]

I'm positive I WOULD NOT look good in a afro <GRIN>

-Overdrive