Athlonix motors from Portescap, a Danaher Motion Co. based in West Chester, Pa. (, use a coreless design with a self-supporting coil and magnetic circuit to deliver maximum power density over the life of the motor. Output power is rated at 9 W and scales with motor frame size, which are available in 12, 16, and 22-mm diameters. The motors weigh between 15 and 53 gm, depending on frame size.

Most self-supporting-coil motors have turn-density limitations which affect magnetic-flux density in the circuit and limit power output and endurance. Althonix’s design maximizes magnetic flux and turndensity for a given diameter. Energy efficiency of these motors approaches 90%.

They also have a motor regulation factor 5 to 20% lower than comparative motors. A lower regulation factor means less heat is lost at high loads, thus letting the motor retain power density over its life despite sustained loads.