H01F 27/422
For instrument transformers
Official title: {for instrument transformers}
H01F27/422 (For instrument transformers) appears on 123 US grants and 115 published applications in this corpus.
Search patents in H01F- Granted patents
- 123
- Published applications
- 115
- Assignees
- 90
- Inventors
- 232
- Latest grant
- 8 Sep 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1979 | 1 | 0 |
| 1980 | 2 | 0 |
| 1981 | 1 | 0 |
| 1982 | 1 | 0 |
| 1983 | 0 | 0 |
| 1984 | 0 | 0 |
| 1985 | 1 | 0 |
| 1986 | 3 | 0 |
| 1987 | 1 | 0 |
| 1988 | 1 | 0 |
| 1989 | 1 | 0 |
| 1990 | 0 | 0 |
| 1991 | 0 | 0 |
| 1992 | 0 | 0 |
| 1993 | 0 | 0 |
| 1994 | 2 | 0 |
| 1995 | 0 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 3 | 0 |
| 1999 | 0 | 0 |
| 2000 | 2 | 0 |
| 2001 | 0 | 0 |
| 2002 | 1 | 3 |
| 2003 | 2 | 0 |
| 2004 | 0 | 1 |
| 2005 | 1 | 2 |
| 2006 | 2 | 0 |
| 2007 | 0 | 1 |
| 2008 | 0 | 1 |
| 2009 | 2 | 2 |
| 2010 | 0 | 0 |
| 2011 | 0 | 2 |
| 2012 | 0 | 2 |
| 2013 | 0 | 1 |
| 2014 | 0 | 1 |
| 2015 | 3 | 5 |
| 2016 | 4 | 1 |
| 2017 | 3 | 12 |
| 2018 | 8 | 23 |
| 2019 | 21 | 10 |
| 2020 | 15 | 10 |
| 2021 | 12 | 6 |
| 2022 | 6 | 13 |
| 2023 | 6 | 4 |
| 2024 | 11 | 7 |
| 2025 | 3 | 2 |
| 2026 | 4 | 6 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- Substrate embedded magnetic core inductors and method of making8 Sep 2026US 12,731,717 B2Intel Corporation
- Current transformer assemblies8 Sep 2026US 12,731,727 B2Schneider Electric USA, Inc.
- Energy management system19 May 2026US 12,633,813 B2Enphase Energy, Inc.
- Circuit breaker device with primary winding turns in opposing directions20 Jan 2026US 12,531,185 B2Rockwell Automation Technologies, Inc.
- Adapter and charging method19 Aug 2025US 12,395,002 B2Guangdong Oppo Mobile Telecommunications Corp., Ltd.
- Shorting block component for a current transformer8 Oct 2026US 2026/0312310 A1Schweitzer Engineering Laboratories, Inc.
- Integrated common-mode inductor and switching power converter having the same27 Aug 2026US 2026/0253778 A1Asian Power Devices Inc.
- Low-power voltage transformer having temperature compensation applied thereto, and temperature compensation method thereof16 Jul 2026US 2026/0202449 A1Hyosung Heavy Industries Corporation
- Circuit breaker device with current sense transformers having primary winding turns in opposing directions14 May 2026US 2026/0135029 A1Rockwell Automation Technologies, Inc.
- Packaged module with low modulus composite magnetic molding material12 Feb 2026US 2026/0047443 A1Monolithic Power Systems, Inc.
Most cited
By later US patents
- Current transformer for measuring instruments46US 4,513,274 ALGZ Landis & Gyr Zug AG · 1985
- Method and apparatus for compensation of current transformer error34US 6,590,380 B22003
- Current measuring and magnetic core compensating apparatus and method24US 4,847,554 ASangamo Weston, Inc. · 1989
- Shunt circuit for an insulation type current transformer to adapt to a wide-band of frequency16US 4,140,961 AMitsubishi Denki Kabushiki Kaisha · 1979
- Current isolator15US 4,243,931 ARosemount Inc. · 1981