Originally published at: https://boingboing.net/2020/09/21/behold-the-sound-of-a-large-electric-motor-spinning-up.html
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Totally unrelated, but what’s up with being unable to full-screen the videos now?
Is this something Youtube is forcing so that you’ll have to click through to their site?
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My favorite is the “Law and Order” chunk-chunk, created by mixing different sounds, including 500 monks walking across a hardwood floor.
Cool, although movies have primed me to expect some be-goggled scientist behind an overly complex control panel, beads of sweat glistening in the light of an indicator whose needle is edging dangerously into a red zone, as a black-gloved hand twists the power dial ever further. . .
Oh well, still satisfying.
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‘Behold’ is for seeing. ‘Hark’ is probably the word you want. Hark unto a large electric motor spinning up. Unless you are looking at the sound on an oscilloscope.
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As much as I enjoyed the video, I cringe at the thought of that motor failing catastrophically. From what I can tell, it’s only secured by (2x) ratchet straps on top of a trailer. Soooo much damage if that thing starts vibrating…
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On what grounds do you assume these people don’t know what they are doing?
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Been to Hoover Dam so i mostly knew what to expect with this electric motor but it is indeed pretty interesting listening to it ramp up during the test on the motor 
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Is that a real-life example of a Shepard tone, or is the pitch actually getting higher?
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The motor hasn’t got any load on it, so there is nothing that should create a force or torque to move it. It should run up to a speed at which the power in equals the resistive loss. There are some special cases where you may have to take care for particular motor designs, but once it is turning steadily, it will probably be safe enough. But they seem to know what they are doing. It’s not the same as getting a car starter motor and plugin it into the mains to see what happens.
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You’re not getting into the spirit of this internet thing
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They’re gonna need a bigger gearbox.
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That thing must have some very good bearings.
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This is an asynchronous motor, so there’s no risk of rotor coming apart and it can’t exceed rated speed. It’s perfectly safe.
Having said that, there are motors that can be dangerous. I own a large (500 kg, 37 or 50 kW) brushed DC motor that was originally used for driving wind tunnel fan at an university. When speed controller fails on that thing, bad things can happen. I guess that’s what happened to one of the wind tunnels. Luckily, flying parts of fan didn’t kill anyone.
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Not sure, but I was compelled to watch to the end hoping for the tension to break and it to finally go to warp…
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Something about the way they’re doing YouTube embeds is truncating the iframe so that the controls are off the screen, I think. You can still full-screen the video by double-clicking it. Anyway, definite site upgrade bug. (Along with effectively neutering the RSS feed, grumble grumble.)
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Since the point of it (afaik) is to spin it up, I assume it actually is getting higher and higher pitched.
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