Just found a load of variacs, any cool things to do with them? - Page 1
Forum section: electronics / beginners

author: corrado33
author_rank: Frequent Contributor
timestamp: February 03, 2016, 09:35:59 pm
content: We have an e-waste here at our school. Today I found about 20 12A variacs that all have "broken" written on them. Well, whoever wrote that must not know the difference between "broken" and "blown fuse" because they all work once the fuses were replaced. (I'm guessing that's the reason why there were so many of them.)I'm going to take one or two home for various projects. I also use them here at work so I'll keep a few to replace the 10A versions we use.Yes, before I plugged them in I tested for continuity between any live wire and the shell of the variac, and also to ground. They all checked out.Anything else I should do with them?

author: vinicius.jlantunes
author_rank: Regular Contributor
timestamp: February 03, 2016, 09:47:11 pm
content: Keep one for donating to me next time I go to the USJust kidding. Nice score.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: February 03, 2016, 09:56:42 pm
content: Wow nice score.What high school or electrical school?if a high school why do they have variacs?if an electrical school why don't they know how to change fuses?

author: edavid
author_rank: Super Contributor
timestamp: February 03, 2016, 10:40:51 pm
content: They make great dimmers for incandescent lights, if you know anyone who still uses those

author: alsetalokin4017
author_rank: Super Contributor
timestamp: February 03, 2016, 10:56:18 pm
content: Good for Tesla coilers, and for anyone who repairs tube electronics, and they make great doorstops. Just don't drop one on your foot..."if a high school why do they have variacs?if an electrical school why don't they know how to change fuses?"USAan educational system.... incompetence rises to its own level.....

author: corrado33
author_rank: Frequent Contributor
timestamp: February 03, 2016, 11:08:47 pm
content: Quote from: HackedFridgeMagnet on February 03, 2016, 09:56:42 pmEven worse. This is at a university.

author: mzacharias
author_rank: Frequent Contributor
timestamp: February 03, 2016, 11:10:25 pm
content: If they are wired up wrong they'll blow a fuse. My guess this is how they got there.

author: Brumby
author_rank: Unknown
timestamp: February 03, 2016, 11:16:11 pm
content: Quote from: corrado33 on February 03, 2016, 11:08:47 pmSeriously?

author: corrado33
author_rank: Frequent Contributor
timestamp: February 03, 2016, 11:38:05 pm
content: Quote from: mzacharias on February 03, 2016, 11:10:25 pmAll of them are stock. I've opened them up and they're all wired correctly. Every single one I've tested so far has just needed a fuse. One of them had a loose solder joint on the on/off switch.It is possible that these are being recycled from storage up in the attic. That doesn't change the fact that someone wrote broken on them when they obviously work fine...

author: Brumby
author_rank: Unknown
timestamp: February 03, 2016, 11:48:21 pm
content: Quote from: corrado33 on February 03, 2016, 11:38:05 pmI thinkmzachariasmeant if they were incorrectly wired into an external circuit. (At least, that's how I read it.)

author: Excavatoree
author_rank: Frequent Contributor
timestamp: February 04, 2016, 02:04:42 am
content: Sell some on E-bay - they bring big bucks.

author: Connoiseur
author_rank: Regular Contributor
timestamp: February 04, 2016, 05:22:07 am
content: Maybe you can get some inspiration from photonicinductionI had once made a servo controlled voltage regulator, unfortunately the motor skipped steps sometimes.

author: nowlan
author_rank: Frequent Contributor
timestamp: February 04, 2016, 06:10:44 am
content: Is possible a chemistry department decided to get rid of them.http://orgchem.colorado.edu/Technique/Equipment/Communityequip/Heatingmantle.html

author: bitshift
author_rank: Regular Contributor
timestamp: February 04, 2016, 08:09:07 am
content: Quote from: alsetalokin4017 on February 03, 2016, 10:56:18 pmYou have clearly never been to South AfricaTo give you a small taste, the percentage required to pass high school is only 30%

author: rickselectricalprojects
author_rank: Regular Contributor
timestamp: February 04, 2016, 08:39:22 am
content: That is a really, really nice score

author: MrSlack
author_rank: Frequent Contributor
timestamp: February 04, 2016, 10:12:01 am
content: This is rife in the education sector. I skip dived (with permission) over 50 BBC Master computers that were less than 4 years old from my school in the late 1980s. Typically the fuse holders would loosen over time due to vibration from they keyboards and they'd not power up so they chucked them and bought new ones. Screw the fuse holder in and all but two were fine. The other two needed some ICs reseating.Idiots.

author: nowlan
author_rank: Frequent Contributor
timestamp: February 04, 2016, 10:52:48 am
content: Id chuck them too if they stopped work after 4 yrs.

author: MrSlack
author_rank: Frequent Contributor
timestamp: February 04, 2016, 10:58:38 am
content: There's stopped working and there's stopped working. One of those machines is still operating a CNC lathe 25 years later with no more maintenance other than doing a screw up hard.

author: Kjelt
author_rank: Super Contributor
timestamp: February 04, 2016, 02:33:36 pm
content: Is it fully isolated or is one the mains connections connected to the output?Things to use it for if it is a normal not isolated variac:- use it to slowly bring very old long time unused equipment (valve radios etc.) back to life , you reform the elco's- use it for experimenting with linear powersupplies- use it as an AC powersupply by connecting an AC transformer (just when you need 12VAC you only have this 18VAC transformer laying around which now is no longer an issue)

author: dfmischler
author_rank: Frequent Contributor
timestamp: February 04, 2016, 03:24:16 pm
content: Quote from: corrado33 on February 03, 2016, 09:35:59 pmIf you know a guitar player with a tube amp see if he wants to play with onea'la Eddie Van Halen(scroll down to AMPLIFIERS).

author: corrado33
author_rank: Frequent Contributor
timestamp: February 04, 2016, 04:55:20 pm
content: Quote from: Kjelt on February 04, 2016, 02:33:36 pmThey are the non-isolated versions... unfortunately.

author: corrado33
author_rank: Frequent Contributor
timestamp: February 04, 2016, 04:57:16 pm
content: Quote from: nowlan on February 04, 2016, 06:10:44 amIt's possible, although not probable here at my university. Other universities I've been to have long since gotten rid of variacs because of the inherent "dangers" in using them, probably due to the fact they're non-isolated.All of these variacs were connected to hot plates for heating chemicals. I'm assuming they were using them to keep the hot plates at a certain temperature (obviously.)

author: saturation
author_rank: Super Contributor
timestamp: February 07, 2016, 09:36:52 pm
content: What brand are they, Staco?

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: February 08, 2016, 05:14:59 am
content: When you select your good pair to keep (and sell the rest), just check the sprung carbon brush that runs on the winding. School units have often been abused and it is common for this little brush to shatter.Regards, BT