초록 ▼

The invention discloses a novel method and apparatus to determine the degree of residual mass unbalance and a corrective balance solution for a rotating assembly having a non-vertical axis of rotation. When the center of mass of the rotating assembly is not concentric with the axis of rotation, the

The invention discloses a novel method and apparatus to determine the degree of residual mass unbalance and a corrective balance solution for a rotating assembly having a non-vertical axis of rotation. When the center of mass of the rotating assembly is not concentric with the axis of rotation, the condition of unbalance exists. When the rotating assembly is driven by a motor or drives a generator, fluctuations in power are produced proportional to the degree of unbalance. The method and apparatus to determine the degree of mass imbalance consists of measuring the average instantaneous real power over an interval of time, calculating the Fourier Transform of the demodulated signal, establishing the peak amplitude and phase associated with the angular velocity of the rotating assembly and calculating the amount of unbalance. The method and apparatus to provide for a corrective solution consists of simultaneously acquiring a position reference signal of the rotating assembly with the average instantaneous real power signal, calculating the phase difference between the two acquired signals at the angular velocity of the rotating assembly, calculating the magnitude of the unbalance, and calculating the quantity and location of corrective weight necessary to minimize the unbalance to an acceptable level.

대표청구항 ▼

1. A method of determining an amount of a mass unbalance torque and a corrective balance solution on a rotational assembly in communication with a means to transform rotational energy, wherein an axis of rotation is displaced by an axis angle of displacement from a gravitational force and the sine o

1. A method of determining an amount of a mass unbalance torque and a corrective balance solution on a rotational assembly in communication with a means to transform rotational energy, wherein an axis of rotation is displaced by an axis angle of displacement from a gravitational force and the sine of said axis angle of displacement is non-zero, the method comprising the steps of: (a) measuring an average instantaneous real power of said means to transform rotational energy over an interval of time,(b) measuring a position reference of said rotational assembly coincidentally with said average instantaneous real power over said interval of time,(c) accumulating said measurements of said average instantaneous real power and said position reference for at least one of revolution of said rotational assembly,(d) performing a mathematical calculation upon said accumulation of said measurements of said average instantaneous power and said position reference to determine an angular velocity, an angular velocity phase and a peak amplitude of said average instantaneous real power and a phase of said average instantaneous real power at said angular velocity of said rotational assembly,(e) dividing said peak amplitude by said angular velocity and a scaling factor to obtain said mass unbalance torque related to rotation of an unbalanced mass,(f) subtracting said phase of said average instantaneous real power and said phase of said angular velocity to obtain an angular displacement from said position reference at said angular velocity,(g) calculating a mass unbalance torque vector equal in magnitude to said mass unbalance torque and having substantially said phase of said average instantaneous real power,(h) determining corrective balance torque vectors wherein the vector sum of said corrective balance torque vectors and said mass unbalance torque vector is substantially nullified and wherein said corrective balance torque vectors substantially coincide with a physical structure on said rotational assembly upon which a corrective weight necessary to produce each of said corrective balance torque vectors is mounted,(i) dividing the magnitude of said corrective balance torque vectors by a radial distance from said axis of rotation of said rotational assembly to determine the amount of said corrective weight at said radial distance for each of said corrective balance torque vectors, and(j) installing said corrective weight at said radial distance on said physical structure for each of said corrective balance torque vectors. 2. The method of claim 1, wherein said scaling factor is the sine of said axis angle of displacement. 3. The method of claim 1, wherein said interval of time is the time for a fraction of one revolution of said rotational assembly. 4. The method of claim 3, wherein the fraction is one-tenth. 5. The method of claim 1, wherein said corrective balance torque vectors are determined by iteratively increasing the magnitude of at least one of said corrective balance torque vectors until the sum of all component vectors, acting in perpendicularity with each other, of a plurality of said corrective balance torque vectors and said mass unbalance torque vector converges to a value which is substantially zero. 6. The method of claim 1, wherein said average instantaneous real power is a discrete value representing an average of discrete samples of instantaneous real power contained in said interval. 7. The method of claim 6, wherein said average instantaneous real power is the output of a low pass filter acting upon said instantaneous real power wherein said low pass filter has a cut off frequency no less than twice the angular velocity of said rotational assembly. 8. The method of claim 1, wherein said interval of time is referenced to an angular position of said rotational assembly, wherein subsequent calculations are based upon constant changes in said angular position of said rotational assembly whereby changes in said angular velocity do not affect subsequent mathematical calculations. 9. The method of claim 1, wherein said mathematical calculation comprises a Fourier Transform. 10. The method of claim 1, wherein a substantially proportional component of said average instantaneous real power is measured and scaled to substantially represent said average instantaneous power. 11. The method of claim 10, wherein said substantially proportional component is at least one phase current from a motor or a generator in communication with said rotational assembly. 12. The method of claim 11, wherein said phase current is an absolute value. 13. The method of claim 10, wherein said substantially proportional component is torque. 14. An apparatus for determining an amount of a mass unbalance torque and a corrective balance solution on a rotational assembly in communication with a means to transform rotational energy, wherein an axis of rotation is displaced by an axis angle of displacement from a gravitational force and the sine of said axis angle of displacement is non-zero, and wherein the means to transform rotational energy comprises a motor or a generator, the apparatus comprising: (a) means for measuring an average instantaneous real power of said motor or said generator over an interval of time,(b) means for measuring a position reference of said rotational assembly coincidentally with said average instantaneous real power over said interval of time,(c) means for accumulating said measurements of said average instantaneous real power and said position reference for at least one revolution of said rotational assembly,(d) means for performing a mathematical calculation upon said accumulation of said measurements of said average instantaneous real power and said position reference to determine an angular velocity, an angular velocity phase and a peak amplitude of said average instantaneous real power and a phase of said average instantaneous real power at said angular velocity of said rotational assembly,(e) means for dividing said peak amplitude by said angular velocity and a scaling factor of said rotational assembly to obtain mass unbalance torque related to rotation of an unbalanced mass,(f) means for subtracting said phase of said average instantaneous real power and said phase of said position reference to obtain a phase difference at said angular velocity,(g) means for calculating a mass unbalance torque vector equal in magnitude to said mass unbalance torque and having substantially said phase of said average instantaneous real power,(h) means for calculating corrective balance torque vectors wherein the vector sum of said corrective balance torque vectors and said mass unbalance torque vector is substantially nullified, and wherein said corrective balance torque vectors substantially coincide with a physical structure on said rotational assembly upon which a corrective weight necessary to produce each of said corrective balance torque vectors is mounted,(i) means for dividing the magnitude of said corrective balance torque vectors by a radial distance from said axis of rotation of said rotational assembly to determine the amount of said corrective weight at said radial distance for each of said corrective balance torque vectors,(j) means for displaying said corrective balance torque vectors, said mass unbalance torque vector, said corrective weight, said angular velocity, a balance quality, and a balance severity criteria,(k) means for storage of said corrective balance torque vectors, said mass unbalance torque vector, said corrective weight, said angular velocity, said balance quality, and said balance severity criteria,(l) means for comparison of said corrective balance torque vectors, said mass unbalance torque vector, said corrective weight, said angular velocity, said balance quality, and said balance severity criteria to stored values of said corrective balance torque vectors, said mass unbalance torque vector, said corrective weight, said angular velocity, said balance quality, and said balance severity criteria. 15. The apparatus of claim 14 wherein said means for calculating said corrective balance torque vectors is accomplished by iteratively increasing the magnitude of at least one of said corrective balance torque vectors until the sum of all component vectors, acting in perpendicularity, of a plurality of said corrective balance torque vectors and said unbalance mass torque vector converges to a value which is substantially zero. 16. An apparatus of claim 14, wherein said interval of time is the time for a fraction of one revolution of said rotational assembly. 17. An apparatus of claim 16, wherein said fraction is one-tenth. 18. An apparatus of claim 14, wherein said scaling factor is the sine of said axis angle of displacement. 19. An apparatus of claim 14, wherein a total time associated with a sum of a plurality of said intervals of time is not less than a time for ten revolutions of said rotational assembly.