GB947169A - Procedures and devices for the balancing of rotating bodies - Google Patents

Abstract

947,169. Measuring dynamic unbalance electrically. W. & T. AVERY Ltd. May 2,1960 [May 14, 1959], No. 15449/60. Heading G1N. Apparatus for determining the magnitude and angular position of the unbalance of a rotor comprises electromagnetic vibration transducers at the bearings, whose outputs are combined with those from a phase-reference generator to give signals indicative of the components of unbalance along alternative axes displaced by 45 degrees, the components being combined electrically to give voltages indicative of the magnitude and phase angle of the resultant unbalance, which are used to control the position of a correcting drill and the depth to which it drills. As shown (Fig. 2a), a test rotor 28 is driven by a motor 23 about a vertical axis together with a phase-reference generator 27. The unbalance signals measured by a transducer 30 are fed to multipliers 52,53 (Fig. 3a) together with sine and cosine signals from generator 27 to establish the values of the perpendicular components of the unbalance N 1 , N 2 , these components being subsequently squared at 58, 59, added together, and the square root found at 62, to be stored as a charge in capacitor 62<SP>1</SP>. After measurement, the charge is removed in unit steps by an interrupter 153, each step causing the correcting drill 41 to be advanced by a predetermined amount, thus producing a hole of the appropriate depth to correct for the measured magnitude of unbalance. The unbalance signals from transducer 30 are also fed to multipliers 84,85 (Fig. 4a) with the sine and cosine signals from generator 27 to repeat the values of the unbalance components N 1 , N 2 . The latter is now inverted at 85b to give 1/N 2 , and multiplied by N 1 at 89 to give N 1 /N 2 corresponding to the tangent of the angle # of the unbalance relative to one set of co-ordinate axes. This signal is stored in a capacitor 92. If the angle # is outside the range 22¢ degrees to 67¢ degrees the value of the N 1 /N 2 signal is too small or too large, and causes operation of a switch 94, whereupon the computation is effected for a set of axes displaced by 45 degrees from the previous axes, giving a different N 1 /N 2 signal, corresponding to the tangent of the angle #<SP>1</SP> relative to the new axes, which is stored in a capacitor 98. The angular position of the drill 41 is correspondingly adjusted by a motor 46 which also drives two sine-cosine resolvers 47 whose rotors are displaced by 45 degrees; giving signals which are formed into a quotient representing tan # and tan #<SP>1</SP>, and the quotient representing an angle between 22¢ degrees and 67¢ degrees is compared with the charge on the appropriate capacitor 92 or 98, any difference being used to energize motor 46 to position the rotors of resolvers 47 and the angular position of drill 41 until the signals are equal. Specifications 744,295 and 789, 376 are referred to.