{
  "$type": "site.standard.document",
  "description": "Electromagnetic noises that accompany the operation of a converter device are decreased in the case where a railroad vehicle runs in the vicinity of a stopping station. If the speed of the vehicle becomes equal to or less than a first reference speed, the carrier frequency of the converter device…",
  "path": "/patents/948668",
  "publishedAt": "2015-09-30T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "B60L9/28",
    "HITACHI LTD [JP]"
  ],
  "textContent": "Electromagnetic noises that accompany the operation of a converter device are decreased in the case where a railroad vehicle runs in the vicinity of a stopping station. If the speed of the vehicle becomes equal to or less than a first reference speed, the carrier frequency of the converter device is changed from a first reference frequency to a second reference frequency, and if the speed of the vehicle becomes equal to or larger than a second reference speed, the carrier frequency of the converter device is changed from the second reference frequency to the first reference frequency.",
  "title": "Drive system"
}