DC Brushless Motors Combine Open Frame Construction with Inner-outer Rotating Irons
Mon, 07/18/2011 - 2:10pm
ThinGap’s laminated-copper DC brushless ironless motors include eight models ranging from 250 oz-in to 600 oz-in of peak torque and maximum continuous speeds ranging from 2,710 rpm to 16,305 rpm. Model 2300 motors are suitable for use in applications that require ultra-smooth velocity, virtually no eddy current and hysteresis losses, no measurable cogging and a high peak torque to continuous torque ratio. The open-frame construction combines with the inner/outer rotating irons to allow designers wide latitude in mechanical integration with the surrounding mechanism. Custom shafts, solid or hollow, are easy for customers to fabricate and install; bearings can be located inside or outside the rotor. ThinGap stators contain no magnet wire windings. Precision etched copper sheets are laminated into a free-standing, lightweight, composite coil approximately 3 mm thick with no iron backing. The design allows free air to flow on both sides of the coil. With no iron backing and the open-frame construction, cooling is exceptional, and increases with rpm. Note that the continuous torque of the motors actually increases with rpm. Also, since the ironless motors do not magnetically saturate, continuous torque is only limited by cooling. Active cooling can be used to extend the SOAC (Safe Operating Ambient Condition) range to even higher torque levels.