Achieving higher torque is a never-ending goal for motor engineers. Pacific Scientific, for example, introduced a high torque step motor earlier this year. And Oriental Motor just announced a new hybrid step motor that has higher torque for a given package. So industry consultant Dan Jones, VP at Motion Media Group (Thousand Oaks, CA) may not have exactly been going out on a limb when he told us that motor torque density will nearly double over the next ten years. He attributes the improvement to new developments in magnets and optimization of motor designs. Magnets improve about 5% each year due to better materials, he says, noting the University of Delaware's research on nano-composites (combinations of soft iron, rare earth elements, and composites). Engineers also are employing finite element analysis to improve pole shaping and exploit more of the effective force of the magnet, and increasing the amount of copper in the windings. Five years ago, the typical motor had less than 60% slot fillótoday that number is in excess of 70% and going up. Earlier this year, for example, Anorad introduced a line of LC linear motors. One of the main selling points: Higher copper fill in the windings. Engineers are also looking to reduce the size of the non-working parts of the motor, which depending on the profile of the motor can take up 50% of the package's real estate.
Californiaís plan to mandate an electric vehicle market isnít the first such undertaking and certainly wonít be the last. But as the Golden State ratchets up for its next big step toward zero-emission vehicle status in 2018, it might be wise to consider a bit of history.