Prior to electric motors, how did machines in factories run?

The first mechanized factories ran on water wheels. The largest utilized multiple waterwheels on one site, and might collectively generate in the neighborhood of 300 horsepower, distributed to machinery via pulleys, belts, and axles. read more

That's largely why many of the electric motors that drive the appliances in our homes, factories, and offices are AC induction motors, powered by rotating magnetic fields, which Nikola Tesla designed in the 1880s (his patent, illustrated here, was granted in May 1888). read more

Machines could be turned "off" by sliding the belt from a fixed pulley onto a loose pulley next to it. By cutting power to the machine, you could then switch the belt onto pulleys of different diameters on the machine, which changed the machine's speed of rotation. read more