Abstract: A vibration state detecting method at a machining stage of a work and/or tool, includes the steps of mounting the work and/or tool on a predetermined rotational device and measuring a deviation size and/or deviation average speed corresponding to each rotational number of the work and/or tool; presetting the deviation size and/or the deviation average speed measured by using the rotational device, a vibration amplitude and/or vibration average speed when each machine tool having a work and/or tool mounted thereon is rotated, with a common unbalance amount and at a rotational speed, and proportional fixed number of both thereof; and calculating a vibration amplitude and/or vibration average speed corresponding to each number of rotations when the work and/or tool is mounted on each machine tool by using a measurement value of the deviation size and/or deviation average speed of using rotational device, and the proportional fixed number.

Abstract: The invention is a machine for balancing drive shafts under computer control. Compensatory weights are formed in a weight-forming dye assembly which is coaxially repositionable in relation to the longitudinal axis of the drive shaft. Additionally, the weights formed are transported along an axis parallel to the longitudinal axis of the drive shaft, and are secured to the drive shaft utilizing a welding head which is selectively positionable along one side of the length of the drive shaft. Sensors are provided to determine the out-of-balance of the shaft, and an associated computer performs the necessary calculations for determining the appropriate position and mass of the compensatory weight.

Abstract: There is provided a method and a apparatus for measuring tire uniformity. The apparatus comprises a spindle, a rotating drum, a sensor and a computing means. The method comprises the steps of mounting a tire on the spindle, pressing a circumferential surface of a rotating drum against the tread surface of the tire with a first pressing force, rotating the tire around rotational axis thereof, and computing the forces which the tire acts on first and second planes of the tire by the computing means while the tire is rotating. The first plane is perpendicular to the rotational axis and in one sidewall side of the tire. The second plane is perpendicular to the rotational axis and in the other sidewall side of the tire. The forces are computed based on values obtained by the sensor measuring forces transmitted to the spindle from the tire at first and second positions. The first and second positions have different distances from the tire in the rotational axis direction.

Abstract: A method of balancing a set of rotating turbine elements includes measuring imbalance in the rotating elements; adding or removing material to or from at least two correction planes in the turbine set at an angular location measured during the imbalance measurement; and, if necessary, repeating said steps of measuring and removing until a predetermined balance is achieved.

Abstract: A method for balancing a wheel and tire assembly includes providing a wheel and tire assembly characterized by a rotational imbalance, and applying a fluid to the wheel and tire assembly thereby to correct the rotational imbalance. The use of a liquid to correct a rotational imbalance facilitates the automation of a balancing operation. Accordingly, another method is provided that includes determining a quantity of mass to be applied to a wheel and tire assembly to correct a rotational imbalance, and commanding an apparatus to dispense an amount of a fluid having the quantity of mass to be dispensed from a nozzle. A corresponding apparatus is also provided.

Abstract: In the case of an imbalance measuring device with a bearing device for static fluid bearing of the rotor (1), to improve the balance quality and to shorten the required time for balancing, it is proposed that the bearing device has at least two open, fluid-supplied bearing shells (11, 11?) to receive sections of the rotor periphery and at least one bearing plate (12, 12?) which is assigned to a rotor end surface and supplied with fluid. The drive is decoupled from the rotor (1) during the imbalance measuring process, and the measuring process preferably takes place during time-variable rotary behavior of the rotor (1).

Abstract: A method of determining an out-of-balance condition of an electronically controlled motor. The method includes: determining a plurality of parameters based on measurements taken from the electronically controlled motor, and calculating a composite score by combining said plurality of parameters into a mathematical transfer function. The mathematical transfer function includes a non-zero weighting factor for each of the plurality of parameters.

Abstract: An improved and simplified balancing machine comprising upright supports devices to hold the workpiece to be balanced, a motor and mount to spin the workpiece, and a system to detect and measure imbalance in the workpiece when it is rotated at speed. Said machine configured to be attached to a machine tool or work table without losing functional integrity, thereby eliminating the need for a massive base. Specific preferred structural embodiments are disclosed.

Abstract: In a method and apparatus for balancing a vehicle wheel, the wheel when fixed to a main shaft of a balancing machine, after the implementation of a wheel unbalance measuring run, is stopped at a given rotational angular position for a balancing operation to be carried out on the wheel, by braking of the rotary movement of the wheel. When the wheel is in the stopped condition, a braking moment derived from the unbalance measurement result and applied by a holding brake is caused to act on the wheel so that the wheel is prevented from rotating of its own accord by virtue of its static unbalance.

Abstract: A control system and method for actively reducing vibration in a spindle housing caused by unbalance forces on a rotating spindle, by measuring the force-induced spindle-housing motion, determining control signals based on synchronous demodulation, and provide compensation for the measured displacement to cancel or otherwise reduce or attenuate the vibration. In particular, the synchronous demodulation technique is performed to recover a measured spindle housing displacement signal related only to the rotation of a machine tool spindle, and consequently rejects measured displacement not related to spindle motion or synchronous to a cycle of revolution. Furthermore, the controller actuates at least one voice-coil (VC) motor, to cancel the original force-induced motion, and adapts the magnitude of voice coil signal until this measured displacement signal is brought to a null. In order to adjust the signal to a null, it must have the correct phase relative to the spindle angle.

Abstract: Certain exemplary embodiments provide a rotating machine assembly comprising a rotor machine assembly including a shaft, a plurality of laminations shrink fit around the circumference of the shaft, and weights affixed therebetween the laminations for balancing the rotating machine assembly.

Abstract: Methods and systems for reducing imbalance in a wheel assembly are provided. The method includes determining an imbalance characteristic associated with a first plane, determining an imbalance characteristic associated with a second plane, and translating a component of the imbalance characteristic from the first plane to the second plane.

Abstract: An exemplary method for balancing a rotating assembly of a turbocharger, where the rotating assembly includes a shaft rotatably supported by a bearing cartridge, includes loading the rotating assembly to introduce a tilt between the rotational axis of an inner race of the bearing cartridge and a bore axis of an outer race of the bearing cartridge, rotating the inner race with respect to the outer race at a rotational speed less than approximately 5,000 rpm while maintaining the tilt at substantially constant angle and measuring dynamic unbalance of the rotating assembly. Various other exemplary devices, systems, methods, etc., are also disclosed.

Abstract: It is possible to determine the types and values of stator and rotor errors in magnetic circuits in a synchronous machine by measuring the induced voltage (ui) for the terminals of measurement loops which can capture an image of the induction in the measurement gap, then by treating said signals.

Abstract: The unbalance measuring device comprises a spindle unit (7) with a spindle holder (29) and with a spindle (11) mounted on the spindle holder (29) rotatably about an axis of rotation (9) and carrying at one of its two ends a coupling for fastening the article to be measured. The spindle unit (7) is combined together with an electric motor (5) for driving the spindle (11) into a first preassembled subassembly. The spindle holder is itself fastened releasably to a machine base (1) by means of a holder suspension (49), the holder suspension (49) itself being combined into a preassembled subassembly together with a sensor arrangement (61) measuring the unbalance forces during operation. For the releasable fastening of the two subassemblies to one another, connecting elements assigned in an indexed manner, for example a dovetail connection (77), are provided. Since the two subassemblies are preassembled, they can be exchanged on site in the event of a repair, without complicated adjustment measures being required.

Abstract: Determining a shaft balance adjustment includes measuring an initial vibration of the shaft, determining if the initial vibration is greater than a predetermined value, and, if the initial vibration is greater than the predetermined value, determining an adjustment by choosing a best adjustment for each possible location for adjustments. Choosing the best adjustment may include choosing an adjustment that causes a lower amount of vibration than adjustments not chosen. Measuring an initial vibration may include using an accelerometer. Measuring an initial vibration may include using conditioning electronics in connection with the accelerometer. The predetermined value may be 0.01 ips.

Abstract: A method and an apparatus for carrying out the method are disclosed for hidden spokes placement of balancing weights on a wheel, having a hub, a rim and the hub and the rim being connected by several spokes, comprising determination of spoke configuration data. Now, it is possible to analyze spoke configuration and width of the spokes in details, enabling the weight splitting behind spokes even if spokes are forked, oblique, not equidistant, or they have different dimension.

Abstract: Correcting unbalance with regard to rotors (11, 101) and shafts is important in order to improve performance of those rotors (11, 101) or shafts within a practical machine or engine. Previously, result orientated iterative balancing of the rotor or shaft has been achieved in which mass has been added or possibly intrusive and distorted adjustments in drag and stiffness presented through bearings or alteration of the rotor (11, 101) itself have been utilised to improve rotor balance performance. In the present invention, a dynamic bearing 13 is utilised in order to provide force components with some components in phase with rotor deflection in order to simulate negative stiffness and/or some force components in phase with rotor velocity in order to simulate negative drag upon the rotor (11, 101). In such circumstances, a more accurate determination of rotor unbalance is achieved to enable known techniques of perturbed boundary condition analysis for balance correction to be implemented more accurately.

Abstract: A device for applying balancing weights to vehicle wheels in wheel balancing machines, comprising: a detector for the position of an indicator that can slide on rectilinear guides with respect to a wheel supported rotatable on the frame of a balancing machine; removable locking elements the indicator in at least one direction of sliding activatable when a preset position of the indicator is reached and comprising at least one first and second gears, supported rotatable on the wheel machine which mesh with each other; transmission elements for transmitting motion of the indicator to the first gear; and motion elements for moving a third gear between an inactive configuration, in which it is disengaged from the first and second gears, and a locking configuration, in which the third gear is engaged with the teeth of the first and second gears to prevent their rotation.

Abstract: A machine for balancing a rotating member includes hard bearing balancing apparatus for determining the magnitude and circumaxial location of imbalance. A sensor responds to the position of the rotating member. A computer receives signals from the balancing apparatus and the sensor and determines the location of one or more projectiles to be fired at the member. A firing mechanism including a piezoelectric actuator fires the projectiles in timed relationship with the rotation of the member so as to position the projectiles as required for balancing.

Abstract: An apparatus for balancing a vehicle wheel simultaneously shows both dynamic imbalance and static imbalance. At least one corrective weight is attached to the wheel to correct the static imbalance. A residual static imbalance is then determined after attachment of the corrective weight. Finally, the corrective weight is adjusted to reduce the residual static imbalance.

Abstract: A wheel balancer includes a microprocessor configured to receive data associated with a vehicle wheel rim and tire assembly imbalance from at least one sensor, and to identify optimal correction weight plane locations, as well as to present the operator with the imbalance correction weight arrangement. The microprocessor is further configured to control a projection display system disposed to project a two-dimensional image onto a surface of the vehicle wheel rim and tire assembly, to facilitate completion of an wheel imbalance correction procedure.

Abstract: A balancer assembly 10 which automatically provides balancer limits, which achieves a balancing state while substantially minimizing short term vibration increases and which provides for multi-plane balancer dithering.

Abstract: An analytical circuit for an inductive electromagnetic sensor with external excitation (1) generates an output signal which is transformed to give an output signal (out), by means of transformation to a reference voltage (Vref) in an inverting low-pass filter (12), which has no hysteresis delay and is free from multiple triggering. By comparison of the reference voltage with three voltage thresholds in a diagnostic circuit (6), line interruptions and short-circuits are recognised by battery voltage or reference voltage potentials.

Abstract: Disclosed is a method for automatically compensating for an unbalance correction position and an unbalance correction amount in a balancing machine. The method involves an unbalance testing procedure, an initial unbalance amount determining procedure, a counting procedure, a good-quality determining procedure, an angular deviation measuring procedure, an angular deviation range determining procedure, and an unbalance correction position and amount compensating procedure in order to automatically compensate for the unbalance correction position and amount of a rotor, based on the unbalance correction amount of a previously-corrected thereby achieving an optimum unbalance correction in spite of the fact that there may be errors in unbalance correction position and amount.

Abstract: A method for automatically balancing a drive shaft about a rotational axis. The method includes providing an unbalanced drive shaft for rotation about a rotational axis to determine an out-of-balance condition with respect to the drive shaft. A plurality of standardized weights or counterweights are provided wherein each standardized weight has a substantially equivalent mass. The method determines an optimal position for placing at least one of the standardized weights on a drive shaft to correct the out-of-balance condition. Standardized weights are then attached to the outer circumference of the drive shaft at the optimal position. The effectiveness of the added standardized weights is verified by subsequently rotating the drive shaft to determine whether an out-of-balance condition still exists. If the out-of-balance condition still exits, additional standardized weights may then be added to the circumference of the drive shaft.

Abstract: A method for determining an optimized position between the tire and rim of a wheel to improve operation smoothness of the wheel. Measurements are conducted to determine respective effects of wheel imbalance and non-uniformities contributed by the tire and rim at different rotational positions. An index vector representing the respective effects is defined. The optimized position is determined based on an observation of changes of the index vector relative to the changes of respective effects of wheel imbalance and non-uniformities contributed by the tire and rim at different rotational positions. The relative position between the tire and rim is adjusted according to the optimized position to achieve better operation of the wheel.

Abstract: An axial position detection circuit detects the axial position of a rotor from the difference in voltages generated at axial position detection coils disposed at both ends in the axial direction of a stator of a canned motor. An axial zero point adjustment circuit uses a voltage supply, which varies proportionately with the power supply voltage of the canned motor, as a bias power supply to adjust the voltage difference of the axial position detection coils to zero when the rotor is at a reference position in the axial direction. Even if the power supply voltage of the canned motor varies, since the bias power supply of the axial zero point adjustment circuit varies in likewise manner, the zero point adjustment by the axial zero point adjustment circuit is not affected and axial bearing wear detection of high precision is enabled.

Abstract: A method of determining a type of corrective weight for application to an edge of a rim of a wheel for correcting imbalance of the wheel, including measuring dimensions of an edge of a rim of a wheel to produce measured dimensions, comparing the measured dimensions to actual dimensions of different types of rim edges, determining a type of rim edge the wheel has based upon the comparison between the measured dimensions and the stored dimensions, and indicating a type of corrective weight appropriate for application to the edge of the rim of the wheel based upon the type of rim edge determined.

Abstract: A system monitoring statuses such as presence and absence of abnormality and lifetime of a machine component such as, for example, a bearing having rolling elements, includes: a plurality of determining units respectively connected with a plurality of sensors, and a control unit connected with the determining units. Each sensor is disposed on the machine component of the associated rolling bearing to detect an influence signal resulting from passage of the rolling element induced in the machine component. Each determining unit determines, according a process set-up condition, the presence and absence of an abnormality and lifetime of the machine component associated with the sensor in reference to an output signal from the sensors. The control unit collects a result of determination performed by each determining unit. In this way, with a simplified structure, monitoring can be achieved at a low cost, precisely and efficiently.

Abstract: A method for providing a centering check for a rotating body mounted on a wheel balancer based on measuring at least one imbalance parameter and for determining weight display thresholds for static and dynamic imbalance correction weights which vary with parameters of the wheel and/or tire. The rotating body is mounted on a spindle of the wheel balancer and an imbalance parameter or runout measurement taken. The mounting of the rotating body on the spindle is then altered, and a second measurement of the imbalance parameter or runout is taken. A processor in the wheel balancer determines if the difference between the first and second measurements exceeds a predetermined threshold value, indicative of off-center mounting of the rotating body one the spindle. Upon centered mounting of the rotating body, imbalance measurements are acquired, and required correction weights are displayed to an operator if they exceed an identified imbalance threshold level.

Abstract: Determining a shaft balance adjustment includes measuring an initial vibration of the shaft, determining if the initial vibration is greater than a predetermined value, and, if the initial vibration is greater than the predetermined value, determining an adjustment by choosing a best adjustment for each possible location for adjustments. Choosing the best adjustment may include choosing an adjustment that causes a lower amount of vibration than adjustments not chosen. Measuring an initial vibration may include using an accelerometer. Measuring an initial vibration may include using conditioning electronics in connection with the accelerometer. The predetermined value may be 0.01 ips.

Abstract: A process for balancing a vehicular driveline including a propeller shaft and an input shaft of a vehicle axle interconnected by a universal joint. First, the vehicle propeller shaft is balanced to a predetermined residual imbalance having an imbalance vector angle of 0° or 180° which lies inline with open set of cardan joint trunnions. The corrected residual imbalance is then visually marked. Next, the input shaft is balanced to a predetermined residual imbalance having an imbalance vector angle of 0° or 180° which lies inline with cross-holes in yoke ears. Again, the corrected residual imbalance on the input shaft is then visually marked. During the assembly of the vehicle, the assembly line operator couples the propeller shaft to the input shaft through a cardan joint cross by aligning the marks on the propeller shaft and the input shaft so that the marks are located opposite to each other.

Abstract: An apparatus for determining balancing information of an object in rotation comprises a base, an arm, a spindle, at least one force sensor, a rolling road, a controller, and an actuator. The arm is rotatably connected to the base about a pivot axis. The spindle is positioned on the arm and receives and rotates the object. The force sensor detects forces generated by the object during rotation of the object. The rolling road includes a surface upon which the object can be positioned. The controller receives force information from the sensor and calculates the balancing information from the force information. An actuator connected to both the arm and the base moves with the movement being controlled by the controller. The object can be a wheel.

Abstract: The present invention provides a system and method for using the external accelerometer in an aircraft engine configuration as a backup accelerometer, in the event the internally located production accelerometer fails. The sensor location of the external accelerometer has an acceptable sensitivity to fan imbalance, similar to the location of the former alternate accelerometer. The signal from this external accelerometer is duplicated using software in the signal conditioning hardware, creating the second, alternate signal. As an alternative embodiment, the signal may be duplicated by simply teeing or branching the original signal, using hardware rather than software.

Abstract: The apparatus (1) comprises at least two balancing rings (10) disposed in axial side by side relationship and coaxial with each other on the rotating body (13) to be balanced. The rings (10) are each unbalanced and rotatable with the rotating body (13), but can each be angularly rotated relative to the latter through positioning members. These members may comprise either a gear (29) that can be selectively engaged in rotation with peripheral toothings (28) of the rings (10) when the rotating body (13) is stopped, to bring the rings (10) to a relative angular position to which the situation of balance of the rotating body (13) corresponds, or locking elements to be selectively engaged with peripheral notches in the rings (10) to retain the rings (10) one by one while the rotating body (13) is rotated relative to the rings (10) through such an angle that the angular balance position is achieved.

Abstract: A method and system for balancing CT gantry mechanisms. Two balance locations are preselected on the rotating base member and stacks of spacers, shims, and weights are provided at each site. Strain gate sensors are provided on the stationary base member and included as part of a sensor circuit. Trial and test runs determine the mass and Z-location of the mass which needs to be added to the system to statically and dynamically balance it.

Abstract: A balancer assembly 10 which automatically provides balancer limits, which achieves a balancing state while substantially minimizing short term vibration increases and which provides for multi-plane balancer dithering.

Abstract: A method and an apparatus for balancing an elongate structure (1) rotating about an axis, like a spindle (3) carrying two grinding wheels (5, 6), wherein two vibration-detecting sensors (7, 8) and associated balancing devices (9, 10) with movable masses (11-14) are arranged at two checking sections (S1, S2) spaced out along the axis of rotation. Processing and control means (20) control the balancing devices on the basis of one or more signals (VC; VC1, VC2) achieved as combination(s) of the vibrations, in module, detected by both the sensors.

Abstract: Apparatus and method for measurement of any unbalance of a motorcycle wheel, having a rotatable main shaft of a wheel balancing machine having an electrical drive, a clamping shaft fixed coaxially with the main shaft and on which the motorcycle wheel is rotatably mounted on its bearings, a driver device which is connected in a non-rotational manner to the main shaft to transmit a torque, produced by the electrical drive, from the main shaft to the motorcycle wheel which is rotatably mounted on the clamping shaft, and a measurement device which, in one measurement run, measures forces from any imbalance of the motorcycle wheel at the measurement rotation speed, where the non-rotational connection between the driver device and the motorcycle wheel can be detached by means of an inertial force, which acts on the driver device and is formed by a torque impulse that is transmitted via the main shall.

Abstract: A system and method are disclosed for dispensing an amount of imbalance correction weight for attachment to a rotary element to reduced an imbalance in the rotary element. The imbalance correction weight includes a number of individual weights provided on a length ot double-sided adhesive tape. A guide directs the imbalance correction weight though the channel provided by the guide toward a tape divider. A driver pulls a protective backing away from the tape causing the imbalance correction weight to move through the channel toward the tape divider. A sensor counts the individual weights that move past it. When the sensor has counted a desired number of individual weights, a controller instructs the driver to stop pulling on the protective backing thereby stopping, movement of the imbalance correction weight and then instructs the tape divider to divide the tape to provide the amount of imbalance correction weight.

Abstract: A wheel balancer includes a shaft adapted for receiving a wheel/tire assembly. The balancer has a longitudinal axis and is rotatable about the axis so as to rotate the wheel/tire assembly removably mounted thereon. A sensor assembly is provided for measuring rotation of the shaft about the longitudinal axis. A vibration sensor assembly measures vibration of the wheel/tire assembly as the wheel/tire assembly is rotated. A motor operatively connected to the shaft rotates the shaft about the longitudinal axis, thereby to rotate the wheel/tire assembly. A load roller applies a generally radial force, which can exceed one hundred fifty pounds, to the wheel/tire assembly during rotation of said wheel/tire assembly. A sensor detects lateral force, wheel/tire assembly radius, and/or wheel/tire assembly diameter, which can have a tendency to cause a vehicle on which the wheel/tire assembly is mounted during use to deviate from a straight line path.

Abstract: A method of measuring a clearance distance between a first member and a stationary member is provided. The method includes measuring the clearance distance using a first probe that is removably coupled at least partially within a mounting adapter, determining a first probe calibration based on the measured clearance distance, measuring a gauge clearance distance using a second probe, and modifying the first probe calibration based on the gauge clearance distance.

Abstract: Measurement is made of centrifugal force produced on a crankshaft to be tested that is being rotated about its rotation axis, to provide centrifugal force variation information of the crankshaft. Also, measurement is made of errors in respective rotational phases of crankpins of the crankshaft about rotation axes of the crankpins. Dummy information, comprising rotational unbalance data representative of rotational unbalance components to be removed from the centrifugal force variation information of the crankshaft, is created using the measured errors in the respective rotational phases. Then, an initial rotational unbalance value of the crankshaft is determined, using the dummy information and the centrifugal force variation information of the crankshaft.

Abstract: A method facilitates simultaneously balancing mechanically coupled, synchronously rotating rotors. The rotors have different axes of rotation relative to one another and together define a rotor group to be balanced. Each rotor has at least one of a bearing plane and an other measuring plane associated therewith, the other measuring plane significantly describing vibrations of the each rotor. The rotors within the rotor group together have a number of different angular velocities associated therewith. At least one rotor of the rotor group is equipped with at least one vibration pickup in at least one of each bearing plane and the other measuring plane thereof. As many impulse and phase transmitters are installed in the rotor group as are provided the number of different angular velocities associated with the rotors within the rotor group.

Abstract: A drive location compensation system determines a deviation between an actual and nominal position of a drive location on a rotor relative to an attachment location on the rotor. The compensation system uses a balancing machine and a sensor that detects when one of the attachment locations passes a known position. Based on the output of the sensor and a known position of a drive spindle of the balancing machine that is coupled to the drive location on the rotor, a relation between the drive spindle and the attachment location is determined. This relationship is compared to a nominal relationship that is based on a calibration standard. The deviation is compensated for during the balancing or the rotor.

Abstract: A method for providing a centering check for a rotating body mounted on a wheel balancer based on measuring at least one imbalance parameter and for determining weight display thresholds for static and dynamic imbalance correction weights which vary with parameters of the wheel and/or tire. The rotating body is mounted on a spindle of the wheel balancer and an imbalance parameter or runout measurement taken. The mounting of the rotating body on the spindle is then altered, and a second measurement of the imbalance parameter or runout is taken. A processor in the wheel balancer determines if the difference between the first and second measurements exceeds a predetermined threshold value, indicative of off-center mounting of the rotating body one the spindle. Upon centered mounting of the rotating body, imbalance measurements are acquired, and required correction weights are displayed to an operator if they exceed an identified imbalance threshold level.

Abstract: A method and a device for moving a wheel rotatably mounted on a wheel balancing machine from a first position at which unbalance compensation has been performed, to a second unbalance compensation position for further unbalance compensation. According to the method, the rotor is externally driven, e.g., by hand, to freely running rotation, at which time, a drive motor is energized to generate a torque which acts counter to the direction of rotation of the wheel and to bring the wheel to a stop over a braking distance brought about by the counter torque which corresponds to the angle of rotation which is traveled over up to the unbalance compensation position, whereupon, the motor is de-energized. The apparatus includes a motor drive including an alternating voltage controller having a longitudinal switching device; and a commutation switching device, the switching devices each including two semiconductor switches which are connected in an anti-serial configuration.

Abstract: A method and apparatus accurately measuring the amount of unbalance of a disc, based on the time to reach a target RPM (Rotation Per Minute) regardless of an assembly condition of a disc drive. The method includes: storing a plurality of reference disc unbalance values; measuring an RPM (Rotation Per Minute) of the disc; comparing the measured RPM with a target RPM; and when the measured RPM reaches the target RPM, detecting a reference disc unbalance value among the plurality of reference disc unbalance values based on an elapsed time to reach the target RPM. Accordingly, the amount of disc imbalance of the disc can be constantly measured regardless of an assembly condition of the disc drive and the computer.

Abstract: A vehicle noise, vibration and harshness analysis tool according to the present invention comprises at least one sensor, each sensing a vibration or noise and generating a signal at a frequency related to the vibration or noise. A communication link with a vehicle is included to transmit data regarding the vehicle. A microprocessor system receives the signals generated by said at least one sensor and receives the vehicle data over said communication link. The microprocessor system conducts an analysis of the received sensor signals and vehicle data and identifies a vehicle component that is likely causing a vibration or noise. The microprocessor system also identifies the possible problems with the identified vehicle component. A user interface is also included with a display. The microprocessor system causes the display to list the likely vehicle components causing the vibration or noise and the possible problems with the components.