Tighten Up: Tight tolerances in
laminations and the stator/rotor air gap minimizes losses to allow high
torque with small step angles in the MAE hybrid motors.
Hybrid stepper motors combine the smaller step angles possible with variable reluctance motors with the higher torque produced by permanent magnet motors. Motors in the MAE series feature step resolution of 1.8 degrees (200 steps per rev) and holding torques (bipolar) from 10 to 3,186 oz-inches.
But to permit such performance, manufacturing processes are critical, says Mike Lefebvre, project manager. In order to minimize losses, tight tolerances for the laminations, stator, and rotor are needed to produce an air gap on the order of a couple of thousandths of an inch and maintain that gap without any rubbing. A unique machine cuts and assembles the laminations into a single assembly. Honing the inner diameter of the stator and the outer diameter of the rotor then provides the required build up.
For high-speed applications, AlNiCo magnets, which have a low energy product, are used in the Y Series because they reduce iron losses at high frequency (speed). These are replaced by neodymium, high energy-product magnets for higher holding and low-speed torque in the N Series. With laminations and a magnetic circuit specifically optimized to use neodymium, S Series motors are configured for maximum torque and smooth microstepping for fine positioning.
Contact:Mike Lefebvre, PennEngineering Motion Technologies
Tel (877) 748-8626; Fax (215) 256-1338