Means for balancing rotors of a machine

摘要

An accelerometer mechanically attached to a machine senses the machine rotor's unbalance and outputs an electrical signal which is indicative of the magnitude and position of the rotor unbalance. A tachometer generator's rotor is mechanically coupled to the machine rotor and outputs an electrical signal delineating the speed and rotational position (with respect to time) of the rotor. By physically indexing one of the tachometer generator rotor poles (north or south) to an index/mark on the engine rotor, the position of the mark at any instant in time is determined. The physical location of the unbalance is obtained by determining the phase relationship of the unbalance signal to that of the tachometer generator signal. This is accomplished by obtaining simultaneous "snapshots" of the two signals employing multiplexing techniques to alternately sample each signal. The signal is then recorded and later reduced by ground equipment. Phasing of the two signals can be visually determined either from the reduced signal or an electronic processor may be utilized to provide a real time measurement of the phasing. The angle between the rotor unbalance and the index/mark is the same as the phasing angle after correcting for any phase shifting due to electronics and rotor resonance.