Patents Assigned to Aerius Oy
  • Patent number: 4982163
    Abstract: The invention relates to a method for the determination of the condition of the insulation of an object (1) made of an electrically conducting material, coated with an electrical insulation (2) and positioned in an electrically conducting medium. According to the invention, the determination of the condition of the insulation is carried out without any electric contact with the object to be monitored in such a way that a first electromagnetic field (6) is created in the conducting medium (3), which field induces eddy currents (7, 8) both in the medium (3) and in the conducting object (1) positioned therein, a second electromagnetic field created by the eddy currents (7, 8) passing both in the conducting medium (3) and in the conducting object (1) is measured in the form of electrical information, essentially excluding the effect of the first electromagnetic field, and said electrical information is analyzed for detecting any changes in the condition of the insulation.
    Type: Grant
    Filed: April 6, 1989
    Date of Patent: January 1, 1991
    Assignee: Aerius Oy
    Inventors: Matti Viikari, Mikko Hamalainen