Abstract: A drive roller has a brushless D.C. motor with a stator or armature mounted on a fixed shaft and directly driving a 16 pole permanent magnet rotor mounted inside a roller tube. A motor controller drive supplies three-phase power to a Y-connected three phase winding having three groups of two coils, forming twelve electromagnets which drive the rotor. The modular motor is readily built in one inch increments to supply one lb-in of torque for each increment. The controller operates at a relatively low frequency of 15-75 Hz. Hall effect sensors provide feedback on motor speed and position. The armature laminations are relatively thick because of the relatively low power necessary to drive the motor and the resultant relatively low eddy currents present in the motor core. A 4.0 lb-in torque motor with a rotor and stator length of four inches will draw approximately 0.8 amps consuming about 15 Watts.

Abstract: The drive roller of this invention utilizes a brushless D.C. motor which has a stator or armature mounted on a fixed shaft which directly drives a permanent magnet rotor mounted inside a roller tube. A variable frequency drive supplies three-phase power to a Y-connected three phase winding which is composed of three groups of two coils. Thus twelve electromagnets are formed which drive the permanent magnet rotor which has sixteen poles. The brushless D.C. motor is of a modular design and can be easily built in one inch length increments to supply one lb-in of torque for each one-inch increment. The variable frequency controller operates at a relatively low frequency of 15-75 Hz. Hall effect sensors are used to provide feedback on motor speed and position. The armature laminations making up the brushless D.C. motor core are also relatively thick because of the relatively low power necessary to drive the motor and the resultant relatively low eddy currents present in the motor core. For a motor with a 4.

Abstract: A conversion frame mounts to pre-existing bolt holes in a conventional USPS tilt-tray carriage with bolts that extend into the holes which previously supported vertical axis rollers for the mechanical drive tilt-tray carriage. The conversion frame has a forward foot and a rear foot, both of which connect to a ferromagnetic driving plate. The feet elevate a connection platform above the driving plate, and provide clearance for the rotation of four positioning rollers which extend sidewardly from the platform on protruding ears. The conversion kit allows the rapid change-over of a conventional mechanical drive tilt-tray sorter system to a LIM drive system with maximum re-use of parts.

Abstract: A drive roller for a conveyor is rotated by a brushless D.C. motor without any intervening gear reducer. The drove roller has a laminated metal stator with at least three windings external to the stator core. The stator is fixed to a rigid axially extending shaft which supports a roller tube and a permanent magnet rotor on bearings. The rotor is fixed to the roller tube and closely spaced from the stator. A variable frequency power supply controls the induced magnetic field in the stator to control the rotational speed of the drive roller.