Provided a vibration measurement device for a rotary tool held by a tool holder that is coupled with a spindle and axially rotates in cooperation with the spindle. The vibration measurement device includes: a pair of acceleration sensors attached to a horizontal plane with respect to a rotary axis of a rotary tool in a manner symmetric to the rotary axis; an amplifier circuit that matches impedance of acceleration information from the acceleration sensors and amplifies voltage; a low-pass filter that removes predetermined high frequencies from an output signal of the amplifier circuit; and a subtraction circuit and an addition circuit that output a parallel vibration signal in an XY direction and a vibration signal in a rotational direction, respectively, from the output signal of the low pass filter.

An abnormality detecting device determines an abnormality in an apparatus by comparing data on vibration detected in the apparatus with a predetermined threshold. Moreover, the abnormality detecting device changes the threshold depending on a length of work time required for the apparatus to perform a certain work.

An abnormality detecting device determines an abnormality in an apparatus by comparing data on vibration detected in the apparatus with a predetermined threshold. Moreover, the abnormality detecting device changes the threshold depending on a length of work time required for the apparatus to perform a certain work.

A sound source estimation system includes a microphone that detects sound which is generated from an object including a rotary device, a rotation speed acquiring unit that acquires a rotation speed of the rotary device, a frequency analyzing unit that generates frequency sound data indicating change of a frequency spectrum of sound detected by the microphone, a degree calculating unit that calculates a degree based on a loudest sound frequency indicating loudest sound out of frequencies of the sound and the rotation speed, and a degree comparing unit that determines a component with a degree closest to the degree as a sound source candidate of the noise.

A sound source estimation system includes a microphone that detects sound which is generated from an object including a rotary device, a rotation speed acquiring unit that acquires a rotation speed of the rotary device, a frequency analyzing unit that generates frequency sound data indicating change of a frequency spectrum of sound detected by the microphone, a degree calculating unit that calculates a degree based on a loudest sound frequency indicating loudest sound out of frequencies of the sound and the rotation speed, and a degree comparing unit that determines a component with a degree closest to the degree as a sound source candidate of the noise.

A method for balancing disc blades comprising the steps of: determining the initial position of the center of mass of the disc blade to be balanced with respect to its main axis; calculating/determining the number, the position and/or the dimensions of one or more balancing holes eccentric with respect to said main axis and necessary for removing an amount of material sufficient to bring the center of mass of the disc blade at a distance from the main axis lower than a predetermined maximum limit value; and forming said balancing hole or holes on the central disc in an eccentric position with respect to said main axis.

A dynamic balancer includes an outer housing and a spindle assembly rotatably mounted to the outer housing. A frameless motor assembly is connected to selected components of the spindle assembly. A chucking assembly receives a locking member to capture a tire therebetween. The chucking assembly and the locking member are captured in the spindle assembly and rotated by the frameless motor assembly. A spring-biased return cylinder may be used with the dynamic balancer to assist in capturing and releasing the locking member with respect to the chucking assembly. An adjustable encoder assembly may be associated with the motor assembly to monitor a rotational position of the tire and/or spindle assembly.

A data recording and transmission method and system for use in balancing a propeller of an aircraft. The method comprises operating the propeller in-flight, receiving, during operation of the propeller in-flight, vibration data associated with the propeller, retrieving, from a non-volatile memory on-board the aircraft, configuration data associated with the propeller, and transmitting the vibration data and the configuration data to a data processing device configured to determine a balancing solution for the propeller based one the vibration data and the configuration data.

A data recording and transmission method and system for use in balancing a propeller of an aircraft. The method comprises operating the propeller in-flight, receiving, during operation of the propeller in-flight, vibration data associated with the propeller, retrieving, from a non-volatile memory on-board the aircraft, configuration data associated with the propeller, and transmitting the vibration data and the configuration data to a data processing device configured to determine a balancing solution for the propeller based one the vibration data and the configuration data.

The invention relates to a method (1) for monitoring a rotating machine (100) of an aircraft, wherein a measurement signal is acquired from the rotating machine. According to the invention, instantaneous frequencies (f.sub.K(t)) of sinusoidal components of the measurement signal are estimated, and, using a computing module (12), a plurality of successive iterations are carried out in each of which: complex envelopes of the components are updated (C1), parameters of a model of a noise of the signal are updated (C21) on the basis of the envelopes, whether the model has converged from the preceding iteration to the present iteration is tested (C4), with a view to: o if not, carrying out a new iteration, o if so, performing a computation (D) of the complex envelopes on the basis of the iterations that have been carried out.