Most electric motors use magnetism to generate torque. While forces from electric fields can also be harnessed to build motors, such electrostatic motors are not deemed sufficiently powerful to compete with their electromagnetic counterparts.

Technology recently patented by Draper promises to underpin a new family of electric motors and generators to benefit an array of applications from electric vehicles (EVs) to mobile defense systems, such as drones, and greatly extend their range and mobility. The e-motors are assembled with thin electrodes and electrets that reduce weight by 80% or more as compared to conventional motors, which translates to a range extension of up to 40% for drones and up to 25% for EVs based on simulations.Electric vehicles, drones and robots are some potential applications for Draper’s new electric motors. Source: Shutterstock

Electrets are dielectric materials with a quasi-permanent electric charge or dipole polarization. An electret generates internal and external electric fields and is the electrostatic equivalent of a permanent magnet.

As described in the patent application, the Draper electrostatic motor includes a cylindrical rotor and a stator. Electrodes are placed on an inside cylindrical surface of the stator. Electrets or electrically conductive electrodes are placed on the cylindrical rotor and a dielectric fluid fills the space between the rotor and the stator to prevent discharge of the electrets. A mask is used to charge portions of an electret cylinder or other curved surface.

The company said its electric motors are designed without the use of rare earth materials, an important consideration in light of rising prices for these materials and reports of China’s potential ban on their export.