Variable autotransformers work well with AC motors that have their field winding connected in series with the rotating armature winding. Used with other AC induction motors you will still have the problem of torque loss due to voltage starvation, although some but not all induction motors can function OK with a limited value of voltage reduction. The SCR (Silicon Controlled Rectifier) type of speed control shown in your video gets around the loss of torque by outputting full line voltage, but portions of the voltage waveform are cut off to reduce the overall power over time supplied to the motor, thus reducing its rpm. I suspect that the power tools' motors you have used with the "Variac" are of the series-wound type, so the setups have worked ok. However it is never a good idea to operate any electric motor (other than a "torque motor" such as used to power locomotives) at very low speed and especially with rotation stopped. This would likely damage the motor permanently.
I own the 480v 10A three-phase beast. Its like a nuclear warhead. Because of the 480v its diameter is like double of this little toy. Its three variacs ganged together on one shaft and bolted together with steel rods and bolts. I dont have a scale but i think its 70 Lbs easy.
I don't know about nowadays, with most lighting being LED or electric discharge, but in old theaters they would use variable auto transformer dimmers, which are physically large but very efficient and not load dependent, still older theaters used resistance dimmers or salt water dimmers, which were highly inefficient and potentially dangerous, as a great amount of heat was dissipated, and salt water dimmers were particularly dangerous because of exposed contacts and they were sometimes nicknamed piss pots, because the salt water heats up and had to be replenished regularly and it smelled like ammonia. Both resistance and salt water dimmers were load dependent and had both a minimum load and maximum load Of course nowadays virtually all dimmers used are Triac based, and work by chopping part of the sine wave, which is what causes incandescent bulbs to buzz when dimming
dont know if you guys gives a shit but if you guys are bored like me atm you can watch all of the new movies and series on InstaFlixxer. Have been binge watching with my brother for the last few months xD
Would it be possible to overload the power tool and cause damage? Nice video, where do I get one, and how much? Who's the manufacturer, kinda looks like square -D?
You'll have to hunt around online the name of the products in the title that really is the name of the company Superior Electric. I don't include product links because I'm not trying to sell these I just review for informational purposes. Yes as I mentioned in the video you do need to be aware of heat build-up when running tools for at low speeds for extended periods of time because of lack of airflow.
@@CatusMaximus Good video! very informative and interesting, learned things i did not know you could do with a variac. I mostly use them for when i am working on my stereos or reel to reel. I just bought one of these models and it has a 32vac 8amp fuse it looks like it is a slow-blow fuse but i am not sure if the voltage is correct for the variac? does yours have the same type of fuse? Thank you
@@CatusMaximus The lady that sold me the powerstat had a voltage variable supply name brand Elema-Schonander made in Stockholm it was a vintage one but BIG and it was a dual power supply 0-30VDC and 0-140VAC rated at 10amps and the input was 220vac and had a big dial on the side of the cabinet just like the one on your variac so i am thinking it was a combination power supply variac and it weighed close to a 100lbs! i had never seen anything like that and she was selling it for $40 i did a google search and could not find any info or images of it. It appeared to be from the 60's the only thing i found out was that the company became Siemens.
@@CatusMaximus I one I bought powerstat type 116 only goes to 118.5 but the dial is set to go to 140vac and that is what it says on the tag, so I don't understand why mine only goes to 118vac? I found a chart online that the 116c is only rated to 140vac.
Ì have one of these l found it to be one of the best voltage transformers speed controller I have ever used for testing I aquired it for free I first saw this type of dimmer at the theater it was used to dim the house lights as the movie started and to brighten slowly when the movie was over it works well for model train sets fans and many more apps
