| 摘要 |
PURPOSE:To surely detect a step out condition by selecting an opening part for its width and a detecting element for its arranging position in an encoder. CONSTITUTION:An encoder 80 provides an opening part 84, and its width La is selected so as to be wider than at least a width Lb of an oscillating frequency generated in the time of step out. A detecting element 85, detecting a rotor condition of the encoder 80, is arranged in almost the central part of the opening part 84 in a direction of rotation of the encoder. By the constitution thus obtained, even when a motor is in vibration generating the step out, the detecting element 85 is prevented from being dislocated from an opening end part of the opening part 84. Consequently, a detecting output in the step out time is obtained equal to when the motor is stopped rotating. As the result, a condition of the step out can be surely detected in a control part. |
