Abstract: The electric generator with the rotational resistance avoidance feature in the present invention comprises a rotating set of magnet parts interposed between at least two rotating sets of conductor coil parts, which are respectively installed on opposite sides of the rotating set of magnet parts. The diameters of the rotating sets of conductor coil parts are configured to be larger than the diameter of the rotating set of magnet parts. The rotational speed of the conductor coil parts and the magnet parts are therefore different, which causes the induction of the electromotive force within the conductor coils by way of variation of the magnetic field.

Abstract: Various embodiments provide a system for moving optical elements. The system includes a first rotor and a second rotor configured to rotate in opposite directions. The system further includes a first plurality of paddles coupled to the first rotor, each of the plurality of paddles having an aperture configured to receive a first optical element, and a second plurality of paddles coupled to the second rotor, each of the plurality of paddles having an aperture configured to receive a second optical element. The first rotor and the second rotor are configured to move the first optical element between a retracted position and a desired position and to move the second optical element between the desired position and a retracted position substantially simultaneously such that a reaction torque of the first rotor cancels a reaction torque of the second rotor.

Abstract: A lithographic apparatus includes a positioner configured to position a first part of the apparatus relative to a second part of the apparatus, the positioner including a motor having a motor position dependent motor constant defining a relation between a motor input and a motor output, and a control system to drive the motor, the control system including a set-point generator to provide a reference signal based on a desired position of the first part relative to the second part, and a controller to provide a drive signal to the motor based on the reference signal, wherein the controller includes a compensator which is configured to at least partially compensate the drive signal for the motor position dependent motor constant. The invention further relates to a positioner, a method to optimize the positioning system, and a method to derive a motor position dependent motor constant.

Abstract: An electric wheel motor assembly generally includes a planetary gearset having a sun gear, a ring gear and a planet carrier that rotatably supports a plurality of planet gears. A portion of a wheel spindle includes the ring gear that is maintained in a non-rotating condition. A first wheel bearing and a second wheel bearing rotatably support the planet carrier on the wheel spindle. The first wheel bearing defines a first plane that extends radially therefrom and the second wheel bearing defines a second plane that extends radially therefrom. An electric motor has a stator and a rotor. A portion of the rotor includes the sun gear. The sun gear has a plurality of gear teeth that are meshed with the planet gears. The sun gear is disposed between the first plane and the second plane.

Abstract: The invention relates to a method and an apparatus (2) for determining an operating state of a motor (4) which is connected to a rigid network (6) and has a rotation speed sensor. According to the invention, phase voltages (ul, u2, u3) of the rigid network (6) which are applied to the connecting terminals (L1, L2, L3) of the motor (4) are used to determine its frequency (fN) and amplitude (U1), a measured shaft rotation speed (n) and a number of pole pairs (p) of the motor (4) are used to determine the slip (s) of the motor (4) as a function of the determined network frequency (fn), and the mechanical shaft power (Pmech) is calculated as a function of this slip (s), of the determined amplitude (U1), of an internal voltage (U11) in the motor (4) and of motor-specific parameters (X1, X2, Xh, R2, R1, Rfe, &sgr;). A method which is independent of power is thus obtained for determining an operating state of a motor (4), without any need to detect the actual current value.

Abstract: An overload release apparatus for a robot supports a cutting tool such as an abrasive grinding wheel. A force sensor detects an amount of force applied to the cutting tool by a workpiece while a force release mechanism reduces the force applied to the cutting tool. The force release mechanism includes an electromagnet secured within a housing, a follower disposed within the housing which is allowed to move both linearly and angularly, and an elastic element interposed between an upper wall of the housing and the follower. During normal operation, the follower maintains contact with and is supported by a shoulder formed on an inner circumferential wall of the housing by an attractive force of an electromagnet. When a cutting tool, such as an abrasive cutting wheel, engages with an irregularity on a workpiece, an axial force and a moment are applied to the follower causing the follower to move both linearly and angularly inside the housing.