Homemade Simple Variac ( Scariac)

This build is a poor man's variac in which two plates in a water bath come close together to let more current through progressively. Very useful in experiments where you need high voltage progressively (I built a plasma generator for which I needed just that).
Grant Thompson made a video on the same subject :
• The Scariac (Poor Mans...

[@acronus]

I'm actually the one that gave Grant the inspiration to build the Scariac. Mine initially was just a 1 gallon bucket with a small metal plate at the bottom and a copper pipe pushed through a small hole in the bucket lid. By adjusting the distance between the plate and pipe, I could adjust the current. I mostly used it as a ballast to prevent tripping the breaker.

[@acronus]

@@338tthompson 😐 You have issues.

[@thomassavoye2519]

vidéo très instructive et intéressante, elle est source d'inspiration pour tout les amateurs de bricolage. je pars bidouiller de ce pas !

[@cancer_sucks]

you are freakin crazy dude. subbed!

[@tomfoubert8859]

Quel talent ! 😍

[@justelectronics2471]

This will be useful for my high voltage tesla coil thank you very much

[@JeanDeBaillEngineering]

Exactly! It can be used for any sort of high voltage project HHO, MOT, Tesla coil, etc

[@blackcappedchickadee2581]

This is exactly my plan for it

[@johndunn9819]

Scariac indeed. well done son of necessity.

[@x1x4x1]

thumbs up for ingenuosity :)

[@JeanDeBaillEngineering]

Thanks, not my idea though

[@ValeJOR]

Very cool

[@JeanDeBaillEngineering]

Thanks!

[@DimitriPappas]

Awesome idea, safety hazards aside. Does it cause electrolysis of the plates (presumably not because it is A/C current?). What about flammable gasses ?

[@yogibogie001]

It awesome for me,,, and i like that......

[@didosauce6008]

Is this just a very large potentiometer?

[@phyx1s]

This a solution you see in B/W frankenstein movies. Fun to see but super dangerous.

[@TempoDrift1480]

Absofuckinlootly!!!

[@raloed.363]

This is basically a high wattage variable resistor. The same as adding a resistor in series with an LED just a much higher wattage. You change the value of its resistance by changing the distance between the plates. The output voltage will be Vin-Vd. Vd is the voltage drop across the water a d is affected by the distance between the plates and the electrical conductivity of the water. The Current is also affected by distance...But I think if you keep the distance the same and increase the surface area then the current should increase without Vd increasing. However please not that this is not a safe method as it have a few hazards. The water could get realy hot if current or run time is high., or if HHO gas accumulate enough and a spark happens an explosion can occur. Also not that the conductivity of the water is affected by its temperature so the regulating stability of this device changes over time. Untill it max out at the highest temperature the water can reach

[@waynoswaynos]

I like this as a concept. Does it get hot? If so how long does it take before the water boils?

[@JeanDeBaillEngineering]

No it doesn't heat or bubble up, it is relatively passive.

[@waynoswaynos]

@@JeanDeBaillEngineering Thanks for the reply. I am so doing a version of this for my too-fast wood bandsaw so I can cut steel. All the best!

[@johndunn9819]

@@waynoswaynos i don't think that will work. i think you'll burn-up your motor because of low (insufficient) voltage/amperage. i put a very big air-conditioner pulley on top and let belt ride on shaft beside lower pulley. i can cut aluminum, brass and fairly thin steel (sheet metal really). but heavier steel is still a no go. what kind of blade would you run?

[@waynoswaynos]

​@@johndunn9819 seems a lifetime ago that I was looking at this but thanks for getting back. I have since learned that induction motors can be slowed down with a triac light dimmer, or probably the 'scariac' but not for too long and must be started at full speed before slowing down. It's the speed of the fan blades within, that cool the induction motor so you probably would not want to run them at half speed continuously. Just last week I acquired a 180v DC permanent magnet motor from a treadmill to replace my bandsaw's induction motor and they slow down very nicely. 110v AC, through a bridge rectifier to make DC, and using a light dimmer to slow it down, had it running lumpy at low speeds. Adding a bank of 6 x 560µf 400v electrolytic capacitors in parallel between plus and minus has it running really smooth and powerful at low speeds. Coupled with the gearing of the bandsaw, it looks promising.

[@johndunn9819]

@@waynoswaynos interesting... and your blade?

[@jimcatanzaro7808]

I fill mine with gasoline so I make sure it works correctly

[@eriktorp-olsen1706]

No more dangerous than DIY brain surgery.

[@daryldixon5280]

Oooooh European scariac

[@MichelBricole]

SUPER DANGEROUS!!! Do not do this at home!

[@JeanDeBaillEngineering]

Indeed, I don't recommend it.

[@amithasanarpon2527]

Like anybody cares... If it's fun, it's a "try it at home" project. I built it and was successful.

[@MrBonners]

Electricity is not some super natural thing. If you understand a few basic things about what it is then you would have no problem with this set-up.

[@juntendo6104]

@@MrBonners but mistakes can happen. Let's make it!!!

[@alexa.davronov1537]

Shut the fuck up and learn electrical engineering. It's not that hard.

[@edwardtheobald5574]

This looks very dodgy, at first he connect a blue wire to moving paddle, then after it cuts to him making connection the wire is green, something not write BE VERY CAREFULL WITH AC CURRENT AND WATER DEATH COULD INSUE