This example shows how to correct imbalance of a rotating object such as a fan or a roller at a certain rotating speed optimal for easy measurement of the imbalance. Imbalance appears as first order vibration of rotation. The HT-5500 detects the reflective mark attached on the rotating shaft to output the rotation signal and the NP-3414 built-in preamplifier type accelerometer installed on the bearing outputs the vibration signal. The DS-3000 series receives these signals and the DS-0227A analyzes them to measure the current imbalance status. Then another imbalance measurement is performed with a trial weight attached anywhere on the rotating object. The position and volume of imbalance are calculated using these two measurement data and appears on the screen. To correct the imbalance, attach a correction weight on the indicated position. Then perform imbalance measurement again for recheck. For this imbalance correction, "one plane-one condition correction", "one plane-two conditions correction", "two planes correction", etc. can be performed. If additionally the DS-0222A is used, resonant vibration etc. can be rechecked through tracking analysis.