| 摘要 |
PROBLEM TO BE SOLVED: To detect the free-fall of a mover and facilitate the short-circuit of each armature winding by a method wherein a short-circuit switch is provided on the output side of an inverter and the short-circuit switch and a feeding switch are closed when the abnormality of an apparatus is detected. SOLUTION: Inverters 21 and 22, feeding switches 31-3n, a controller 5 and an abnormality detector 6 are attached to a linear synchronous motor. Short- circuit switches 41 and 42 are connected to the output sides of the inverters 21 and 22. If the service interruption or the abnormality of an apparatus is detected by the abnormality detector 6, the feeding switches 31-3n are excited. If the contacts are closed, the contacts which operate when the abnormality exists are excited and the coils of the feeding switches 31-3n and the short- circuit switches 41 and 42 are excited to close the feeding switches 31-3n and the short-circuit switches 41 and 42. Therefore, all armature windings are short- circuited and short-circuit currents are applied and a generative braking force is applied to the synchronous motor. As a result, it can be avoided that the mover of the linear synchronous motor apparatus which operates a vertical movement falls freely when an abnormality is produced in the apparatus. |
