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Are these scavenged parts good for a ZVS?

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HM_Murdock

Wed Aug 18 2010, 05:35PM

Registered Member #3075 Joined: Fri Aug 06 2010, 02:44PM
Location: Athens, GA
Posts: 148

That is exactly who I just spoke with

I am going by there tomorrow at lunch.

And thanks quicksilver...great tips!

Plasmana

Wed Aug 18 2010, 08:22PM

Registered Member #3108 Joined: Thu Aug 12 2010, 05:37PM
Location: Worthing, England
Posts: 72

Quoted by radiotech:

Is that discoloration on the case ? Kinda looks a perished compact fluorescent lamp.

I assume that is caused by heat or UV from the lamp?

Quoted by quicksilver:

To defeat a great amount of varnish without destroying the insulation, a hairdryer and get that warm enough to unwind without solvents (occasionally - sometimes it's ridiculous).

Wow! Thanks for mentioning that tip! I always wandered how people managed to salvage magnet wire from motors, transformers, etc. I just wished I didn't throw away my AC motors a few months back...

HM_Murdock

Wed Aug 18 2010, 09:56PM

Registered Member #3075 Joined: Fri Aug 06 2010, 02:44PM
Location: Athens, GA
Posts: 148

Papa's got a brand new...board!

Stopped by local car stereo shop, and look at what they were going to throw away...

at the very least, I plan on using that toroid to wire my inductor (or should I just use the one already wound next to it...), and the heatsink is going to come in real handy.

The FET's are IRFZ44N's...the Vdss is only 55V best I can tell...no idea if they are any use, but I suspect they are too small?

Plasmana

Wed Aug 18 2010, 11:01PM

Registered Member #3108 Joined: Thu Aug 12 2010, 05:37PM
Location: Worthing, England
Posts: 72

OMG! That is a very nice find! Look at all of those chunky semiconductors!

Anyway, you can use any MOSFET's that has the Vds rating 4 times the supply voltage. The IRFZ44N should do fine if you are running the ZVS driver at 6v (you would get very tiny arcs though). At 12v, you would be pushing to the limit however they should still work, probably not for very long - you can always experiment!

quicksilver

Thu Aug 19 2010, 04:09PM

Registered Member #1408 Joined: Fri Mar 21 2008, 03:49PM
Location: Oracle, AZ
Posts: 679

Some items are over-looked and when you need them; you REALLY need them. I make a special effort to grab heat sinks and simply put them in a separate collection. They can cost quite a bit individually.

I'm fairly sure you know this but when collecting semiconductors / transistors, occasionally size indicates a capacity of higher than common place capacity. Learn the package configuration ON SIGHT via any catalog. If the thing has a TO-247, i4-PAC, RD-91, TO-3, SOT-227, or DO-203 (or 205) package configuration; GRAB it! Often times those configurations are designed to handle higher values. Although there ARE TO-220 packages that will also have some great designs. Developing that habit & hunting those down can yield a very serious savings.

Occasionally the transistor (or whatever) will be very difficult to read. A magnifying glass and some correction fluid (tiny drop wiped over the impression) will revel the impression.
There is a "look-up" program that is made by NTE electronics that can be invaluable because it cross-references manufacturers. Naturally they try to sell the NTE component; however for a product that you have a limited set of I.D. numbers for, especially semi-conductors, transformers, & tough to find items that Digikey just doesn't seem to find the free-standing program (now at v15.) is worth installing on your computer:

It's their free cross-referencing program & database. It won't have the depth that you will get from the Mfg datasheet but it will have a link to that datasheet and will have the basics; so you will know if you DO have that special HV diode or whatever. It saves a great deal of time because of the active links within it to access the datasheet if you need more than the basic specs.

HM_Murdock

Thu Aug 19 2010, 06:06PM

Registered Member #3075 Joined: Fri Aug 06 2010, 02:44PM
Location: Athens, GA
Posts: 148

Great info Plasmana and quicksilver!

Between the FET's on that board and the ones from my other boards (monitor and TV), I have a few to play with and see what I can get out of them

Right now, I am running 12V max (found out the hard way you can't run two different PSU's with different wattages in series), but I hope to move to 24V at some point...

I also hope to be able to use mostly 'found' parts for my experiments, so info like how to choose the transistor and that lookup DB are crucial!

Xplorer

Fri Aug 20 2010, 09:51AM

Registered Member #2416 Joined: Sun Oct 04 2009, 04:23AM
Location: Oceanside, CA
Posts: 91

Hey Murdock, how many turns are you going to wind on that toroid you found? I found a 2cm ferrite toroid and I think about 22 turns will get about .170uH, but I'm not sure.

-Tony

HM_Murdock

Fri Aug 20 2010, 12:27PM

Registered Member #3075 Joined: Fri Aug 06 2010, 02:44PM
Location: Athens, GA
Posts: 148

Xplorer...

I don't really know yet. I don't have the experience or the theory to know, so it's going to have to be trial and error.

Plasmana suggested 20 turns of 18AWG magnet wire on the large bobbin I have, so it sounds like somewhere around 20-22 should make a working circuit...

But I am just guessing...if he had said 100, I would be trying that...I see no reason to re-invent the wheel, so I do try and learn from other people's experiences and build from there. Sometimes you get good advice, sometimes not...but it's better than a cold SWAG (Some Wild Ass Guess)!

Xplorer

Fri Aug 20 2010, 02:57PM

Registered Member #2416 Joined: Sun Oct 04 2009, 04:23AM
Location: Oceanside, CA
Posts: 91

This might help.

If the toroids we have are purely magnetic iron (permiability = 200) then yeah 20-22 turns should do it with a 2cm toroid.

-Tony

Conundrum

Fri Aug 20 2010, 09:46PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

Yep, old microwave oven fan or stirrer motors have this wire, I dicovered this a little while ago.

The newer ones unsportingly use varnish which spoils things.

Also, another worthwhile source of short lengths of ECW are dead brushed motors from old VCRs or printers, a few seconds dismantling and voila.

So EPE "Rat it before you Chuck it" on making a metal detector from a broken tape recorder isn't as ridiculous as it sounds, use the tape deck's counter to count the turns on the former, centre tap the coil and then use it in a basic Hartley oscillator using the deck's input amplifier and record bias oscillator as the heterodyne.

-A
"Bother" said Pooh, as the transporter beam lost annular confinement...

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