Post #3352213

@mlanger@mastodon.world Might be an inertial power backup (also known as flywheel UPS) ... giant rotating wheel that provides power in the gap between a grid power failure and when the data center's backup generators come online. They absolutely try to minimize anything that might cause noise (because that would just waste energy and shorten the bridge time) by putting them in vacuum enclosures and riding the rotor on magnetic bearings, but they generate some low frequency vibrations.