| 摘要 |
<p>PURPOSE:To enable removing a frequency component detrimental to a security track circuit without enlarging a filter circuit within a main circuit by forbidding the use of a specified rarnge of power frequency of an inverter. CONSTITUTION:If an electric rolling stock starts a power running, a rotational frequency fM of an induction motor 26 rises gradually and a power frequency fINV of a VVVF(variable voltage variable frequency) inverter 25 also ascends in accordance therewith. If the power frequency of the VVVF inverter 25 is found to be so high as to exirt an influence upon a security track circuit at a point of time t0, the power frequency fINV is shifted somewhat upward. At a point of time t2, then, shifting of the frequency flNV is stopped and an operation of said rolling stock is restored to its original condition.</p> |
