The Biggest Rheostat You've Never Seen. 

Biggest rheostat I ever saw in person was backstage in high school. Six feet in diameter with the resistive elements made out of cast iron. There were six of them in a row and they were used to adjust the brightness of different stage lights. You moved a hand lever up and down to turn it. I looked but didn't see a name plate. I would have liked to know what the total resistive range was.

i actually saw one for a train turntable if i remember right i think it was about 6ft around , the table is now gone but was very cool

That would be a fun knob for something. 😎

Slight correction, if I may, rheostats are two-terminal, pots are three-terminal. You don't have a three-terminal rheostat. The power handling's nothing to do with it. Your "2-1/2a rheostat" is a 2.5a-rated wirewound potentiometer. Oh, and the rheostat with the "off" spot? I about guarantee it's got a log taper, too -- specifically an _audio_ log taper -- rather than linear. Wirewound pots and rheos like that, those were common on old tube radios and the like. I've got a 30s-era blooper set (it needs a replacement tube, but otherwise it'd work fine) that uses one of those. Also, no, those terms _are_ specific and not synonymous or fungible. However, if you need to specify something as "either a rheostat or a potentiometer and it doesn't very much matter which", you can simply call it a -- "variable resistor"! ;3 But, hey, for the most part, great vid and tutorial.

most of the small pots are 0-infinity logarithmic, especially for audio or signal

6:53 That's not entirely true! For the sake of the demonstration it's mostly doing nothing. But your meter is bouncing a bit and that's not just random noise. The wiper is occasionally shunting two adjacent windings due to how they are constructed to overlap and 'make before break' of each connection. So the wiper is having a measurable effect. Technically it's also a capacitive node moving down an inductor and has RF connotations like tuning.. but that's more a tangent and less measurable or important in practice. 14:01 Don't you mean the resistance will go higher? Identical to above, the band is shunting 2 resistant windings, so removing the shunting metal will make the resistance go up. I wouldn't expect a power rheostat to have amazing tolerances TBH, but if it actually goes down towards 50, I'll eat my non-existent hat, or at least be very confused.

Sir, can we make a test load with a rheostat

largest rheostat i've seen on youtube is photonicinduction's

If still in use, the liquid rheostat's that NASA uses at the National Transonic Facility to vary the speed of the wind tunnel dwarf the rheostats that you have. They have 3 of them. They are something like 6 foot in diameter and 18 foot tall.