GB821556A - Method for the balancing of rotors and balancing machine for the carrying out of themethod - Google Patents

Abstract

821,556. Measuring rotor unbalance electrically. LOSENHAUSENWERK DUSSELDORFER MASCHINENBAU A.G. Aug. 25, 1956, No. 26053/56. Class 40 (1). [Also in Group XIX] In order to ensure that the compensation required by an unbalanced rotor should be effectable within a predetermined angle in two predetermined balancing planes, the unbalance is augmented by an additional amount in one or more compensating planes, all the unbalance quantities being measured electrically, the compensating unbalances being initially introduced as a voltage of variable phase and magnitude which is adjusted until the resultant out-ofbalance is shown on a C.R.O. as being within the predetermined angle in each balancing plane. As shown (Fig. 1), a crank-shaft 5 to be balanced by drilling the counterweights 11, 2<SP>1</SP>, 3<SP>1</SP>, 4<SP>1</SP>, is supported in spring bearings 6, 7 so that lateral vibrations are sensed by piezo-crystal pick-ups 12, 13. The signals from the pick-ups are fed across series potentiometers 14, 15 and combined in a ratio defined mathematically so that the voltage between the sliders 14<SP>1</SP>, 15<SP>1</SP> is indicative of the unbalance in plane 2 only. Auxiliary . voltages of the same frequency are obtained from generators 16, 17, rotating synchronously with the crank-shaft 5, the phase of these voltages being adjusted by rotating the field windings and indicated by pointers 19. These voltages are operated on in potentiometers 21-24 in ratios defined mathematically so that they represent additional unbalances in planes 1 and 4, and are then algebraically added to the previous signal representing the unbalance in plane 2, the resultant signal being fed through an amplifier 25, and phase-sensitive rectifiers 26, 27 to a C.R.O. 31 where the position of the spot on a radially calibrated screen indicates the magnitude and angular position of the required compensation in plane 2. The magnitude and phase of the auxiliary voltages from the generators 16, 17 are adjusted until the spot on the C.R.O. screen appears within the angle in plane 2 wherein drilling is allowable. The process is repeated for plane 3, so that the amount and position of the compensation in all four planes 1, 2, 3, 4 is known. An apparatus is described which enables the mathematical ratios to be obtained mechanically.