Patents by Inventor Andrew L. James

Andrew L. James 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: 5563506
    Abstract: Electronic electricity meter, in which the electrical energy consumed by a load is evaluated using a signal indicative of voltage supplied to the load and a signal indicative of load current. The load current signal is derived from an estimated load current value produced by a current transformer (4). The meter includes a memory (9) storing one or more constants from equations indicative of how current transformer phase and ratio errors vary as primary current varies. An adjusted value for the load current is produced by calculating the phase and/or ratio error using the stored constants and the estimated load current value and correcting the estimated load current value to eliminate the error. Alternatively, the meter includes a memory (9) storing a plurality of values of phase error and/or ratio error for a respective plurality of primary current values of the current transformer of predetermined configuration.
    Type: Grant
    Filed: March 24, 1995
    Date of Patent: October 8, 1996
    Assignee: Polymeters Response International Limited
    Inventors: John S. Fielden, Andrew L. James, Barnaby J. McCabe