Coreless DC motors

Coreless DC motors differ from traditional DC motors in significant ways. The most obvious and important difference is the rotor winding.

Instead of coils wound around a stack of iron laminations, the coil is formed as a thin hollow cylinder .

The stator with its permanent magnets supplies the magnetic field flux and fits in the hollow center of the winding. It’s rigidly affixed to the outside motor housing , which completes the magnetic circuit. The rotor is supported by bearings  and rotates around the magnetic core.

Coreless DC motors are usually small in size, ranging from 6 mm (0.24") to less than 75 mm (3") in diameter. Continuous power is normally limited to 250 Watts or less.

They are a preferred choice for many medical devices, small pumps, and document handling/dispensing equipment.