How electric motors are made

The stator is a stack of thin steel sheets, insulated from each other so currents cannot swirl inside the core.

stations: 6
things upstream: 44
raw sources: 15
steps from the ground: 7

The short version

An electric motor has a fixed stator and a spinning rotor. Thin sheets of electrical steel are stamped out and stacked to make the stator core, which is wound with copper wire. The windings are soaked in varnish under vacuum. A rotor with its shaft is fitted on bearings, and the housing is closed.

Stamp the laminations

Thin sheets of electrical steel are punched into ring and disk shapes, each insulated from the next. A solid core would allow wasteful circulating currents, so the core is made of thin plates.

Goes in
Sheet steel
Stack the stator core

The laminations are stacked and bonded into a tube with slots on the inside.
Wind in the copper

Coils of copper wire are wound and pushed into the slots. Current in these windings creates the magnetic field that drives the rotor.

Goes in
Copper wire
Varnish under vacuum

Mains-powered AC motors have their windings impregnated with varnish in a vacuum. This holds the wires still so they do not rub through their insulation. Some motors are packed in plastic resin instead.

Goes in
Epoxy
Fit the rotor and bearings

The rotor and shaft are set inside the stator on bearings, with end plates holding everything in line.

Goes in
Ball bearing Steel
Spin test

Each motor is run to check speed, current and vibration.

End of the lineElectric motor Next it goes into refrigerator, microwave oven, washing machine and 13 more.

Worth repeating

An electric generator is mechanically identical to an electric motor but works in reverse.
Resin-packed motors are used in deep-well submersible pumps, washing machines and air conditioners.
Most electric motors work through the force between a magnetic field and the current in a wire winding.