Patents by Inventor William Frederick Ray

William Frederick Ray 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: 9970963
    Abstract: A temperature compensated current measurement device comprises a Rogowski coil having a terminating impedance arranged to adjust the attenuation of the coil to balance changes in coil sensitivity so that the output voltage indicative of measured current remains substantially unchanged, the terminating impedance having different values above and below a threshold frequency.
    Type: Grant
    Filed: February 1, 2013
    Date of Patent: May 15, 2018
    Assignee: Power Electronic Measurements Limited
    Inventors: William Frederick Ray, Christopher Rene Hewson, Joanne Marie Aberdeen
  • Publication number: 20150015244
    Abstract: A temperature compensated current measurement device comprises a Rogowski coil having a terminating impedance arranged to adjust the attenuation of the coil to balance changes in coil sensitivity so that the output voltage indicative of measured current remains substantially unchanged, the terminating impedance having different values above and below a threshold frequency.
    Type: Application
    Filed: February 1, 2013
    Publication date: January 15, 2015
    Inventors: William Frederick Ray, Christopher Rene Hewson, Joanne Marie Aberdeen
  • Patent number: 6614218
    Abstract: A current measuring device comprising a Rogowski coil (30). Connected across ends of the coil (30) is a passive integrator in two parts (34, 36), the parts being connected by a coaxial cable (32). Connected to the output of the passive integrator (34, 36), is an electronic integrator (38). At low frequencies the passive integrator (34, 36) has a substantially constant gain and the electronic integrator (38) integrates the signal from the coil (30). At high frequencies, the electronic integrator (38) has substantially constant gain and the passive integrator (34, 36) integrates the signal from the coil (30). In order to reduce high frequency voltage oscillations, the Rogowski coil (30) is terminated with a coil damping resistor that has a value that is approximately the same as a characteristic impedance of the coil.
    Type: Grant
    Filed: October 18, 2000
    Date of Patent: September 2, 2003
    Assignee: Power Electronic Measurements Limited
    Inventor: William Frederick Ray