the presence of a large imbalance causes larger speed fluctuations of the drum during prebalancing which in turn causes the automatic balancers e g balls to react more quickly which in turn shows up as a large rate of imbalance reduction i e high uc it has been found that when the rate of imbalance reduction is high a balanced position can be reached very quickly this is desirable if on the other hand the rate of imbalance reduction is too low long prebalancing times result leading to the undesirable dynamic imbalances there exists a limiting value for the rate of reduction of imbalance referred herein to as uc min if the rate of imbalance reduction uc is lower than uc min the speed of rotation of the wash basket must be reduced so as to effect the movement of the laundry it should also be noted that the rate of change of imbalance is proportional to the rate of change of speed fluctuations correspondingly the condition for uc can be substituted by the condition for the rate of change of speed fluctuations as schematically illustrated in fig1 the actual value of uc min will differ from machine to machine and depends at least in part on the type of wash load and the amount of imbalance it has been found for example that for a 5 kg domestic washing machine with a stiwa standard wash load the rate of change of imbalance uc should be smaller greater than a level which would result in a balanced situation in less then 15 20 sec because imbalance causes speed fluctuation and imbalance is reduced through the action of prebalancing the speed fluctuation decreases with a considerable imbalance the initial speed fluctuation may be.