ROTATION STATE DETERMINATION DEVICE

To provide a rotation state determination device capable of determining a rotation state of a rotor or a support part supporting the rotor when the rotor is rotated by a motor.SOLUTION: A rotation state determination device comprises a motor 30 for rotating a roll 14 which is supported in a freely rotatable manner by bearings 26 and 28. A driving current of the motor 30 is calculated as a detection value I(t), and a torque T(t) is detected. The torque T(t) is converted into a current value to calculate a conversion value Ik(t), and an estimated regenerative current d(t) is calculated from the detection value I(t) and the conversion value Ik(t). A matching rate (e) within a measurement time range t0 is calculated from the estimated regenerative current d(t) and as the matching rate (e) is lower, a rotation state of the roll 14 or of the bearings 26 and 28 are determined worse.SELECTED DRAWING: Figure 1 【課題】モータによって回転体を回転させる場合に、回転体やその回転体を支持する支持部の回転状態を判断できる回転状態判断装置を提供する。【解決手段】ベアリング２６，２８に回転自在に支持されたロール１４を回転させるモータ３０と、モータ３０の駆動電流を検出値Ｉ（ｔ）とトルクＴ（ｔ）を検出し、トルクＴ（ｔ）を電流値に換算して換算値Ｉｋ（ｔ）を求め、検出値Ｉ（ｔ）と換算値Ｉｋ（ｔ）とから推定回生電流ｄ（ｔ）を求め、この推定回生電流ｄ（ｔ）から測定時間範囲ｔ０内における合致率ｅを求め、合致率ｅが低いほどロール１４、又は、ベアリング２６，２８の回転状態が悪いと判断する。【選択図】 図１