METHOD OF CONTROLLING ROTATION SPEED OF MOTOR OF SPEED-CONTROLLABLE HOIST DRIVE, AND HOIST DRIVE

摘要

A method according to the invention of controlling a rotation speed of a motor of a speed-controllable hoist drive comprises receiving a lift speed instruction (?'m )/ forming a final speed instruction (?m ) by using initial information con- taining the lift speed instruction (?'m ); and using the final speed instruction (?m ) as a speed instruction for the rotation speed of the motor of the speed- controllable hoist drive. The method further comprises monitoring a position derivative of an actual value of a cable force (dF/dz). The initial information for forming the final speed instruction (?m ) comprises the position derivative of the actual value of the cable force (dF/dz).