Coreless Brushed DC Motors

How does a coreless motor function?

Coreless brushed motors function similarly to traditional or cored brushed motors. With a coreless design, magnetic fields are induced by applying current and voltage to the rotor windings, which react with the  permanent magnet on the stator to convert electrical energy into mechanical energy. A coreless dc motor is typically constructed with rare earth magnets to maximize performance and mechanical strength from such a small form factor. An electric micro motor like this needs the best materials in order to have a high starting torque and rapid mechanical time constant.

The removal of the iron core, within the housing cylinder, leads to other advantages as well. Armature Windings dissipate heat more efficiently without an iron core holding onto the heat in the middle of the motor. This improved thermal performance allows a coreless dc motor to to radiate its heat through the casing, removing the need for air holes of active cooling.  In turn the sealed casings help to reduce both audible noise as well as electrical noise or EMI, making coreless motor well suited for applications sensitive to electromagnetic interference.

Motor Design Notes

Coreless motors are revolutionizing the micro-automation industry. An encoder or hall sensor can be attached to a dc electric motor to create a coreless brushed servo motor. A mini motor like this can be used in place of a stepper motor to save on weight. Miniature motors in general have seen a rise in popularity, as more machines and devices incorporate them for their unique advantages.