GB1144933A - Improvements relating to force-measuring dynamic balance machines - Google Patents

Abstract

1,144,933. Measuring rotor unbalance electrically. W. & T. AVERY Ltd. May 6, 1966 [June 18, 1965], No.20240/66. Heading G1N. A dynamic balancing machine for determining the compensation masses required at each of two compensation planes A1, A2 Fig. 1 in a rotary test body computes equations:- F A1 = [F 1 .a/b - F 2 c/b] + F 1 and F A2 = [F 1 .a/b - F 2 c/b] - F 2 Relating forces F A1 , F A2 acting in compensation planes A 1 A 2 to forces F 1 , F 2 measured by electro mechanical transducers in measuring planes 1, 2. Corresponding potential expressions - [a/b.U F1 - c/b . U F2 ] + U F1 . (i.e. voltage between terminals 10 and 0) [a/b . U F1 - c/b. U F2 ] - U F2‹ (i.e. voltage between terminals 20 and 0) are set up on a potentiometer arrangement Fig.2, U F1 and U F2 being the voltages of the pick-up transducers 31, 32 respectively, each transducer providing two voltages corresponding to measured bearing forces. Means for setting up the logarithmic potentiometers is illustrated in Fig. 3 (not shown), one potentiometer being connected across one pick-up output and the other potentiometer across the other pick-up output. A calculating aid (43) is used to set up the values a/b and c/b and comprises a movable element on which are two logarithmic scales movable relative to a fixed pointer set to give value b. Two movable pointers are adjusted to give values a and c respectively and are mechanically coupled to the sliders of respective potentiometers. In a further embodiment Fig.4 (not shown) compensation masses in relation to rotary speed and balancing radius are determined by a similar potentiometer arrangement set up to solve equation - m u N(U/r.n.n) 2 wherein m u is the unbalance or compensation mass. n is the rotary speed. r is the radius whereat the unbalance mass acts. U is the voltage determined by a moving coil. pick-up transducer.