How does a Variac autotransformer work? Practical demonstration. Variac opened and tested - tutorial

What is a variable AC transformer supply?
What is inside a variac?
What does a variac do?
How does a variac work?

[@spaceted3977]

My 2 Kw 0 to 300 volt digital Variac has arrived !!! I'm using it with a Residual Current Device and I don't check high voltages with my fingers !!!! I wanted it to repair power tools, electronics, machines etc. You can turn the voltage down to 0 which stops a power tool and you can see it working at whatever speed you want !!!! I can't see a Router spinning at 30,000 rpm, but I can if it's moving slowly !!!! I think it's a brilliant machine !!!!!

[@30mAkills]

An unfused output will damage the variac if the device under test has short fault. My experience. I use quick blow glass fuse of same rating as that of variac.

[@randyyuwono3298]

Thank you for the tutorial, it is very well explained and clear. I’m just curious, if the resistance across the output terminal is so low (0.5 ohms) would that just mean short circuit?and the current will NOT flow through the load? If I apply 120V for example at input then put a 1A fuse, would it just blow immediately?

[@ecologicaltime]

When AC current flows in a long wire such as an inductor, the inductance builds an impedance so under higher frequency such as 50 Hz there is a much higher impedance and it wont be a short circuit

[@randyyuwono3298]

@@ecologicaltime Thank you that makes sense!

[@spaceted3977]

Oh !!! I wasn't sure exactly how it works !!! Thanks !!!!

[@BeingRomans829ed]

Thank you very much for this video. I plan to install a variac in a wooden box and wire it up and this is very good information.

[@BeingRomans829ed]

@@ecologicaltime Thank you very much. I too was confused about the DC short, but I forgot about the inductive reactance.

[@Tridenux]

Does varic effect output current?