Patents by Inventor Janne HOLLA

Janne HOLLA has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 10877098
    Abstract: A method for detecting a fault in an AC/AC exciter having an exciter rotor and an exciter stator. A signal reflecting the current or voltage, is obtained at an exciter rotor winding or at an exciter stator winding. A frequency analysis is applied and on the basis of a presence of a frequency component, a rotor current or voltage signal, at a first frequency fs*(2?s), where fs is a supply frequency of the exciter stator and s is an exciter slip, it is determined whether the exciter suffers from an inter-turn short circuit in an exciter stator winding or not. On the basis of a presence of a frequency component, in the case of a stator current signal or a stator voltage signal, at a second frequency fs*(1?2*s), it is determined whether the exciter suffers from an inter-turn short circuit in an exciter rotor winding or not. Presence of frequency components at the first and/or second frequencies in windings of an AC/AC exciter indicate the mentioned fault conditions.
    Type: Grant
    Filed: September 22, 2017
    Date of Patent: December 29, 2020
    Assignee: ABB Schweiz AG
    Inventors: Pedro Rodriguez, Matti Kivioja, Janne Holla, Tapio Rauhala, Ilari Karkkainen
  • Publication number: 20200057110
    Abstract: A method for detecting a fault in an AC/AC exciter having an exciter rotor and an exciter stator. A signal reflecting the current or voltage, is obtained at an exciter rotor winding or at an exciter stator winding. A frequency analysis is applied and on the basis of a presence of a frequency component, a rotor current or voltage signal, at a first frequency fs*(2?s), where fs is a supply frequency of the exciter stator and s is an exciter slip, it is determined whether the exciter suffers from an inter-turn short circuit in an exciter stator winding or not. On the basis of a presence of a frequency component, in the case of a stator current signal or a stator voltage signal, at a second frequency fs*(1?2*s), it is determined whether the exciter suffers from an inter-turn short circuit in an exciter rotor winding or not. Presence of frequency components at the first and/or second frequencies in windings of an AC/AC exciter indicate the mentioned fault conditions.
    Type: Application
    Filed: September 22, 2017
    Publication date: February 20, 2020
    Inventors: Pedro RODRIGUEZ, Matti KIVIOJA, Janne HOLLA, Tapio RAUHALA, Ilari KARKKAINEN