Apparatus and Method for Compensating Secondary Currents Used in Differential Protection to Correct for a Phase Shift Introduced Between High Voltage and Low Voltage Transformer Windings
US 7,425,778 In forceTerm ends Jan 16, 2027 · High confidence
20-year base term ended Jul 22, 2025
Jul 22, 2005
Jan 16, 2027
Sep 16, 2008
How we calculated this date
| Step | Input | Date after this step | Confidence |
|---|---|---|---|
| Base term, 20 years from filing | Clock starts Jul 22, 2005, when this application, 11/188,237, was filed | Jul 22, 2025 | High confidence |
| Continuity chain | Every parent in the chain resolved | no change | High confidence |
| Patent term adjustment | +543 days, USPTO patent term adjustment record | Jan 16, 2027 | High confidence |
| Terminal disclaimer cap | None on record | no cap applied | High confidence |
| Patent term extension | None on file | no change | High confidence |
| Fee events | 3 of 3 maintenance fees paid | In force | High confidence |
| Computed term end | The steps above, in order | Jan 16, 2027 | High confidence |
Sources
Google Patents · The patent document at USPTO · Assignment records at USPTO
USPTO account required: This application in Patent Center · USPTO's maintenance fee lookup
Maintenance fee events come from USPTO's own fee records. Its fee lookup asks for the patent number and the application number.
Not on this page: the patent's family, its recorded assignments and its citation count. USPTO's assignment records, linked above, list every recorded assignment.
Every date shows its work: the base term, any term adjustment or extension, any disclaimer cap, and the maintenance fee record, each with a confidence tier. How this record was built
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In force means the term is running and no lapse is on record. It is not a finding that the patent is valid.