Abstract: The invention relates to a device for measuring a rotor imbalance. Said device comprises a main shaft which is rotatably mounted in a machine housing and to which the rotor to be measured is fixed, a single-phase alternating-current motor for driving the main shaft, with a single-phase winding (4) and an auxiliary winding (5) which is offset in phase for driving the main shaft (1) up to measurement speed and a control device (17) that adjusts the current of the motor. Said control device (17) has an assembly (8, 6; 7; 20; 22, 23) which reduces the supply current delivered to the two windings (4, 5) of the motor (3; 21) once the measurement speed has been reached, in such a way that the motor creates a reduced torque which substantially compensates a speed drop produced by friction and drag.

Abstract: The invention relates to a device for measuring a rotor imbalance. Said device comprises a main shaft which is rotatably mounted in a machine housing and to which the rotor to be measured is fixed, a single-phase alternating-current motor for driving the main shaft, with a single-phase winding (4) and an auxiliary winding (5) which is offset in phase for driving the main shaft (1) up to measurement speed and a control device (17) that adjusts the current of the motor. Said control device (17) has an assembly (8, 6; 7; 20; 22, 23) which reduces the supply current delivered to the two windings (4, 5) of the motor (3; 21) once the measurement speed has been reached, in such a way that the motor creates a reduced torque which substantially compensates a speed drop produced by friction and drag.

Abstract: An unbalance measuring machine has an arrangement for clamping and release a motor vehicle wheel or other rotary member on a motor-driven shaft. The machine has a bar which is guided movably in the shaft in its axial direction. The bar is engaged at one end with the rotary member and at the other end with a belt pulley via interengaged screw threads. When the belt pulley is driven by the drive motor in one direction of rotation, the bar axially clamps the rotary member on the shaft to hold it fast. When the belt pulley is driven by the drive motor in the other direction, the bar moves in the opposite direction to release the rotary member.

Abstract: An apparatus and method for correcting unbalance of a motor vehicle wheel by at least one balancing weight has a sensor for sensing at least one predetermined position on the wheel, a position detector connected to the sensor for detecting the position thereof, and a storage device connected to the position detector for storing position data determining actual balancing positions on the wheel. An electronic evaluator is connected to a measuring arrangement for measuring wheel unbalance requiring correction and to the storage device for determining the balancing position and the magnitude of the respective balancing weight to be fixed to the wheel. A comparator is connected to the storage device and the position detector. In a retrieval mode, when the sensor reaches a position which corresponds to a stored balancing position a clamping device receives a clamping signal from the comparator for at least partially blocking displacement of the sensor.