A balance assembly for a rotating assembly comprising: a first movable
rotor and a second movable rotor which are selectively movable about the
rotating assembly; and a controller with a microprocessor operating with
stored control programs for controlling movement of the first movable
rotor and second movable rotor and adapted to calculate a value and to
periodically modify the value and to cause the first movable rotor and
the second movable rotor to move in accordance with the calculated value
and the modified value, wherein the values are adjusted during a
plurality of control iterations to reduce vibrational signals from an at
least one vibration sensor.