Melting a bearing - GIF

[Altair]

Melting a bearing.




Previously:

Melting rock using a Fresnel lens - GIF
Melting a machine gun barrel by firing 700 rounds through it - GIF
Solid mercury melting in water - GIF
Melting a padlock - GIF
Melting a wrench with electricity - GIF

[Floradawg]

Ultrasonic energy?

[desbromilow]

honestly looks like top and bottom contacts are the terminals of a large current source (think large spot welder source) and the bearing is acting as a dead short. The current flowing through the outer race heats it enough to soften it, then the bearing balls/race improve contact with the outer race and they become a lower resistance than initially, so they then heat up, and as they heat, the contact to th einnner race improves, therefoe lowering resistance, and lastly the inner race becomes part of the circuit and heats up.
The current source for a flashbutt rail welding machine is capable of thousands of amps, and if this bearing is relatively small (say 1- 1.5" bore) then a source like that could easily accomplish what we're seeing in the video.