METHOD OF DETERMINING THE UNBALANCE OF A LAUNDRY DRUM

摘要

Before switching the spin dry program of a washing machine (11) to the highe st spinning revolutions, the unbalance caused by uneven distribution of clothes (12) in the drum (13) should be checked once again on the basis of the momentary spinning revolutions. The spin dry program should be optionally aborted if the danger of too high bearing forces caused by the centrifugal force arises. In view of the fact that fluctuations in rotational speed duri ng a rotation at high mass inertia as a result of high drum charge are very har d to measure and the reception of periodical fluctuations in the alternating current power received by the drum drive (14) from the household mains netwo rk (22) is dominantly overridden by the network frequency and other network interferences, the rotational speed-dependent high frequency fluctuation in power reception (dP/dt) of the washing machine motor (14) is measured behind the direct current intermediate circuit (26) before it is fed into the inverter (18) for generating a rotating field in the motor (14), wherein the product from the current (28) and voltage (27) for measuring the unbalance b y power determination (dP/dt) is protected against mains interruptions by the high capacity (25) of the direct current intermediate circuit (26).