Patents by Inventor Leif Ericksson

Leif Ericksson 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: 4352136
    Abstract: In an impedance-measuring device for impedance protection, the phase positions of a plurality of alternating-current quantities are compared with the aid of a phase comparator. From the output signal thereof it is clear whether the impedance in a fault loop with a voltage U and a current I lies inside or outside an impedance zone, which is defined by means of a model impedance, Z.sub.k =R+jX. The comparator is supplied with input quantities corresponding to IX, U.sub.k, I and preferably also U.sub.p, where U.sub.k =U-IZ.sub.k, whereas U.sub.p relates to a voltage which is phase-shifted -90.degree. with respect to U. Quantities corresponding to IX, U.sub.p and I are each supplied to one input of a second logic component. This second logic component also has an input which is connected, via a delay element, to the output of a first logic component, the two inputs of which are supplied with quantities corresponding to I and U.sub.k, respectively.
    Type: Grant
    Filed: August 26, 1980
    Date of Patent: September 28, 1982
    Assignee: Asea Aktiebolag
    Inventor: Leif Ericksson