GB1071498A - Dynamic balancing of rotating bodies - Google Patents

Abstract

1,071,498. Dynamic balancing of rotating bodies. W. & T. AVERY Ltd. Oct. 30, 1963 [Nov. 3, 1962], No. 42751/63. Heading G1N. Unbalance in a rotating test body is to be corrected on any of three "balance components" A1, A2, A3 positions which are angularly displaced by 120‹ in one plane, the 360‹ circle of rotation of the test body being divided into sectors I, II, III by the said balance components. To determine the component of unbalance force at each of the balance component positions each balance component is associated with two measuring components one lying 30‹ in advance of and one 30‹ after the balance component. Each measuring component is characterized by a voltage which is the product of a voltage representative of the unbalance and a reference voltage produced by a 3 phase generator rotating at the same speed as the body. Fig. 3 is a diagrammatic electrical circuit wherein the components are represented vectorally in accordance with their angular displacement relative to the rotation circle of the test body, their phase displacement in electrical degrees being determined by their manner of connection in an electrical circuit Fig. 9. In Fig. 3, balance components Al, A2, A3, have associated measuring components - V, W; - U, V; U, -W respectively. Associated with each measuring component is a multiplying element 15 to 20 e.g. a Hall generator, which is fed with a reference voltage of appropriate phase and with an unbalance representative voltage also of appropriate phase. Direct potentials of varying size and polarity arise at the outputs of the said elements 15 - 20 corresponding to the phase position and magnitude of the unbalance voltages fed to these elements. Rectifiers 28 to 33 ensure that positive direct potentials only are fed to an appropriate evaluation device or indicator 34, 35, 36, which may be moving coil galvanometers. If for example the output voltage of Hall device 15 is higher than that of 16 then the rectifier 29 will be blocked and the indicator 34 will respond to the voltage of 15 only. In Fig. 9 output voltage from an oscillation detector 10 is fed to a transformer primary, the three secondary windings 12, 13, 14 of which are each respectively connected in series with a pair of Hall generators. A 3 phase generator 21 energizes Hall generator windings 15a, 16a, 17a, 18a, 19a, 20a in a correct phase relationship. The amplified outputs of the Hall devices are fed to the indicators 34, 35, 36 as in Fig. 3. OPERATION - Consider for example an unbalance vector lying in Sector I (Fig. 3), 60‹ from A1 and 60‹ from A2. The output voltage of Hall devices 16 and 17 will be positive and will be fed via rectifiers 29, 30 to indicators 34, 35 respectively. Since the unbalance vector lies at 90‹ to components V and -V the output voltage of Hall devices 15 and 18 will be zero, and the voltages of 19 and 20 will be negative since the angular difference between measuring components U and -W is greater than 90‹ and will be blocked by rectifiers 32, 33 from the indicator 36. The unbalance present will thus be shown on the indicators 34, 35. Other examples are described with reference to Figs. 6, 7 and 8. Allowance for the angular difference between the balance and measuring components, is made on the calibration of the indicators. Arrangements for balancing in two planes are briefly described with reference to Fig. 10 (not shown).