A new electromagnetic method for the nondestructive evaluation of electric pumps with ball bearings is proposed. A permanent magnet generates a static magnetic field and a coil of several hundred turns wrapped around it is used to pick up eddy currents induced inside rotating ball bearings and impellers. First, a method that makes use of the autocorrelation is applied to the signals of the ball bearings. A relation between the processed signals and the size of the defects in the bearings is obtained....
英字タイトル:
Electromagnetic Nondestructive Detection for Wounded Bearings and Correlation of Size of Defect and Signal

Experiments that simulate bearing failures and the presence of cavitation are performed on a pump loop. During the experiments several types of data are acquired such as vibrations, system pressure, flow rate and motor current. A multivariate analysis is then applied to these data. Abnormalities are detected by evaluating the residual between the measured value and the estimated value that is determined from the model in a normal state. Because the influence of bearing failures is limited to a very loc...
英字タイトル:
Evaluation of a Multi-Sensors Condition Monitoring Method

This study aimed to establish the method for evaluating the amount of bearing flaking in balls. We performed 5 accelerated aging tests of ball bearing s that expedite the occurance of flaking in balls and analyzed the vibraion signal. Some characteristic features for initial stage of flaking in balls are revealed such as sudden decrease of vibarion level or pulse vibration once per several revolutions of a ball. Those knowledge can be used for diag nosing the severity of bearings that indicate the existanc...
英字タイトル:
A Study on Evaluating the Amount of Bearing Flaking in Balls

A new electromagnetic method for the nondestructive evaluation of electric pumps with sliding bearings is proposed. A permanent magnet gen erates a static magnetic field and a coil of several hundred turns wrapped around it is used to pick up eddy currents induced inside rotat ing impellers. This electromagnetic nondestructive evaluation method is applied to the canned pump. By monitoring the movement of the impe ller in a canned pump, the rotation speed, the variance of the impeller position as well as th...
英字タイトル:
Study of Evaluation Method for the Amount of Wear-Out of Plain bearingswith Electromagnetic Sensor

The epochal electromagnetic nondestructive detection method was proposed. In that method a permanent magnet is zed to generate static magnetic field and a several hundred turn coil is used to detect the eddy currents induced inside ball bea rings. In the present study the signal procedure method of a autocorrelation method is also proposed in tion to that detection method and these methods are applied to observe and evaluate ball bearings wounded by grinder. erimental validatio ns are carried out using a c...
英字タイトル:
Lectromagnetic Nondestructive Detection for Wounded Bearings and Proposalof the Signal Procedure Method for Estimating the Wound Width

A new electromagnetic method for the nondestructive evaluation of gears is proposed. A permanent magnet generates a static magnetic field and a coil of several hundred turns wrapped around it is used to pick up eddy currents induced inside rotating gears. This electromagnetic nondestructive evaluation method is applied to the rotating machine with gears. By monitoring the movement of the gear in a rotating machine, the wear of teeth of gear has been evaluated. ...
英字タイトル:
Study of Evaluation Method for the Amount of Wear-Out of Gears with Electromagnetic Sensor