ABYMC

[T3sl4]

I will, soon. You really need a few instruments (multimeter, oscilloscope, function generator, and knowing how to use them) to put it together, though.

The problem is, we're in the same situation. I'm a poor college student, and you're poor too (if you'll forgive my bluntness ). So you can't afford to buy one, and I can't afford to give you one. I know you love to trade, but I wonder what would be a fair trade... maybe the materials for three units? Heck, you might get lucky and find that at the junk yard. Hmm...

Tim
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Librarians are hiding something (tm)

[metalmaster1766]

were you being blunt? I must have missed it,

no need for forgiveness, it doesn't bother me, I'm broke and most likely will be for a few more years, it doesn't bother me, I'm still living the American dream, well, I'm still living

if I knew what to look for I might have a good chance of finding it at the scrap yard, and as far as those instruments go, I can get my hands on most of them probably, the guy that owns the scrap yard (he has since leased it out to another guy to run) but anyway he has a few engineering degrees, I don't know if he has an electronics degree but I guess if I ask him I will find out, I'm sure he might even have the instruments that you listed

so, how about a list of materials to build one about the size I asked about, 2 inch inside and no longer than 4 inches, I'm sure I could figure out the copper tubing coil part, but the total length needed may be where I would need help, not knowing how far it has to reach from the coil to where ever it goes from there,
maybe a simple drawing with a list of materials I'm sure I could get one going, it just might take me 2 years to buy all the parts, but I would buy a list and drawing if it isn't to much, I'm not talking a step by step plan type kit, just a drawing and list of materials, the drawing should show what and where each piece goes, just something simple

I don't know what all is left at the yard, I just know he has gotten rid of a lot of things because the city was giving him trouble about how high he was piling stuff, heck I haven't been down there in 3 maybe 4 months, I can't drive that far anymore, I just call and talk to him about once a week now

just let me know if you can do that, I will give you a fair price for a drawing, if I would need further help with it I'll pay for the help you give, just wait for the money then give me what I paid for kinda deal, I understand if you don't wanna do it, but I would see what I can get from the yard if he has whats needed

dadgum my head has been hurting for the past 32 hours, I hope I'm making sense, so please excuse my ignorance if I seem to be repeating myself

Ron SS

[T3sl4]

Well, the most expensive parts that go into it are all the mechanical parts (a fair amount of copper tubing, and the chassis is easily a $200 value if you were lazy enough to get it fabricated... which we aren't ), and some of the power components. The tank capacitor is about $60 for the parts, and you need a 50A contactor, and preferrably a 50A switch as well, to turn on and off the 240V line. It also should have an RFI filter, which is easily $200 new, but I can make one myself for much cheaper (wind some 8AWG wire around a magnetic core!).

You can probably find most of the stuff from junk, industrial or otherwise. The only things you'll probably have a hard time finding are all the capacitors and magnetic cores required. They're probably best purchased new. Oh, and the transistors, but they are a surprisingly small part of the cost.

Now, when I say 'magnetic core', I mean black ferrite toroids. Like this:
http://webpages.charter.net/dawill/Images/Induction1002.jpg
Those are slightly over 3" across. You probably won't find many that big. You might get lucky if you find a big UPS (Uninterruptible Power Supply): these often have a big switching power supply inside them, which already makes them most of an induction heater. You might find a rectangular or E-shaped core inside, instead of toroids; either will work.

Also around any kind of switching power supply, you will find little boxy capacitors like those here:
http://webpages.charter.net/dawill/Images/Induction1006.jpg
The trouble is finding enough of the same type to stick together. When you need two hundred of something, you pretty much have to buy it. Fortunately, they are fairly cheap.

If you have a lot of electronic junk to go through, look for boxy capacitors which say things like 'MKP', 'X type' or 'X1' or 'X2', '0.1uF' (or '104' somewhere in the part number), 250V or more (probably 250 or 275VAC, or 400 or 630VDC). Types that aren't suitable are MKT, values too large (more than 0.22uF (or '224') will draw too much current and cook itself), values too small (you'll need too many!), and voltages too low (you shouldn't even see one less than 250VAC or 400VDC, since it wouldn't even stand up to the AC line it's designed for!).

You can recognize both sorts of components, and some power resistors and a contactor, in the photograph,
http://myweb.msoe.edu/williamstm/Images/Induction1201.jpg
Oh, and the white striped/black cylinders behind the board in front, those are the filter capacitors. I pulled all of those out of computer power supplies. You can probably find a pile of old supplies in a corner of the junkyard. Chock full of 'em. I soldered together 16 for this.


I wouldn't expect to see electronic test equipment in a junkyard, nothing working at least. You can find good deals on used equipment -- a Tektronix 475 oscilloscope (also excellent are the 465, 2235 and similar, and if you're feeling nostalgic, any of the tube based 5xx series) can easily be found for $50 in working or near-working condition. You can get away with a pretty cheezy signal generator as well, which will hardly cost as much. A meter good enough can be bought for $10, if you don't have one already.

Tim
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[metalmaster1766]

thank ya very much Tim

I'll ask around for different things now that I know what to look for


what I really need to do is start studying up on electronics and that sort of thing, I know very little as it is but I'm willing to learn anything I can now, I just wish I would have thought about that sort of thing 15 - 20 years ago

as far as finding good stuff at the junkyard, you would be surprised what comes thru there, plus the fact that he does a lot of company clean outs, he doesn't only do machinery, and junk, he only started the scrapping business to keep him busy and make a bit of money everyday, like I said he may have all the electronic equipment, he is a very intelligent man, if I ask him if he has any of these parts needed he may have them or point me into the right direction to get them new and used

he has equipment that ages stuff with ultra violet rays that they test materials in for shoes, vinyl tops for cars, or whatever to see how it will be effected in daily life and the life expectancy of such things

heck, maybe I'll just take the parts off his Induction furnace (if the thing was smaller I would bring it home, but it uses way to much power, that's why he hasn't hooked it up), he has had it for many years and once a month the company that made it sends him a letter about hooking it up, something about they need to inspect it because if it is hooked up wrong or a wire is crossed it can cause a serious electrical explosion of some kind that will put out enormous amounts of radiation of some kind, I can't remember exactly what it was, but he explained it to me one day when I was there and he got the letter in the mail when I was talking to him about Induction furnaces

thanks again, I'll start looking for parts, and just maybe I can learn a bit about this before I gather all the stuff needed, this will be a goal I will set to get started and finished before I die


Ron

[T3sl4]

How big is it, like 100kW or more? That'll be 3 phase supplied, and from the kinds of voltages that don't shock 'ya, but turn you into mist!

Tim
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[metalmaster1766]

[T3sl4]

That thing looks old, does it have tubes inside?

Worse, is it motor generator?
http://websites.labx.com/sciex/detail.cfm?type=details&autonumber=26270
That one looks like it is...

Stuff hiding in the control panel might be handy... those meters, buttons, the things they activate (relays / contactors?), and the knobs look like variacs, which are always nice to have. It probably has a load of capacitors somewhere, with big switches on them to adjust tuning. Most of the "big amps" parts are probably too big, but worth a look anyway.

Tim
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[metalmaster1766]

Those do look exactly alike, I do know he has had it for at least 15 years

and I noticed this - Inductotherm 100 KW, maybe his is only 50KW, but then again I have no idea

Ill hafta ask him if he wants to part it out to me, I seriously doubt it, but what can it hurt to ask, after all. I just want to build a forge so I can forge weld faster and easier

this morning I was looking at several youtube videos on induction heating used for forging, most of them said DIY induction heating, but all they had were video's of them heating a piece of metal, nothing with any tech information on them

I'll figure it out someday and get one going, all I have is time, so I just need to learn the basics 1st

can you recommend any good books to read about this subjects? I can walk to the library and read anything, it is only about a 1 mile walk from my house, unless if I cut thru my neighbors yard, but I'll need to get my step ladder out to get over the fence, which is not a problem

thanks again for all you have told me so far, I appreciate it greatly


Ron

[T3sl4]

Yeah but can you run from the guard dogs?

I don't know of any books offhand, do run a search and check it out though. Your library might have an online catalog available, so you don't even have to leave your seat to find out.

Lindsay Books has at least one on the subject. Old, but that'll make it easier to understand, I suppose -- back in the days when tubes were all they had. Matter of fact, if you had some transmitter tubes, I'd recommend you build one that way -- a lot simpler, and you can see everything that's going on. Downside is it requires ten times the voltage...

Tim
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Librarians are hiding something (tm)

[metalmaster1766]

no guard dogs, plus he only lets me cut thru, he has sensors up around the perimeter of his property, so if anyone does cut thru and heads my way he will call me and warn me, he's a hell of a guy, he watches out for me all the time and I watch out for him as much as I can

and get this, today I go to the scrap yard and ask him about about an oscilloscope, and he tells me he just threw all of the ones he had out this past summer, if only I would have known I may need one sooner

he also told me that just before I met him that he scrapped a bunch of small induction heaters that were used for silver soldering stuff together

I'm always a day late and a dollar short, just my luck, but the good news is, he may still be able to get a few of these small induction heaters used for silver soldering, so maybe I will get lucky and get 1 or 2 for real cheap and be able to make a larger one to the size I want

only time shall tell


Ron

[AdamZiegler]

http://hackaday.com/2010/06/04/1000w-induction-heater/