H01F 38/28
Current transformers
H01F38/28 (Current transformers) appears on 547 US grants and 481 published applications in this corpus.
Search patents in H01F- Granted patents
- 547
- Published applications
- 481
- Assignees
- 319
- Inventors
- 1,131
- Latest grant
- 15 Sep 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 7 | 0 |
| 1977 | 5 | 0 |
| 1978 | 2 | 0 |
| 1979 | 5 | 0 |
| 1980 | 3 | 0 |
| 1981 | 8 | 0 |
| 1982 | 7 | 0 |
| 1983 | 1 | 0 |
| 1984 | 6 | 0 |
| 1985 | 8 | 0 |
| 1986 | 6 | 0 |
| 1987 | 9 | 0 |
| 1988 | 11 | 0 |
| 1989 | 7 | 0 |
| 1990 | 4 | 0 |
| 1991 | 5 | 0 |
| 1992 | 4 | 0 |
| 1993 | 6 | 0 |
| 1994 | 6 | 0 |
| 1995 | 9 | 0 |
| 1996 | 12 | 0 |
| 1997 | 0 | 0 |
| 1998 | 6 | 0 |
| 1999 | 4 | 0 |
| 2000 | 9 | 0 |
| 2001 | 4 | 0 |
| 2002 | 6 | 6 |
| 2003 | 10 | 11 |
| 2004 | 9 | 7 |
| 2005 | 7 | 9 |
| 2006 | 6 | 6 |
| 2007 | 3 | 10 |
| 2008 | 4 | 13 |
| 2009 | 14 | 12 |
| 2010 | 11 | 18 |
| 2011 | 9 | 19 |
| 2012 | 9 | 21 |
| 2013 | 10 | 22 |
| 2014 | 20 | 40 |
| 2015 | 29 | 22 |
| 2016 | 24 | 30 |
| 2017 | 24 | 20 |
| 2018 | 21 | 28 |
| 2019 | 22 | 26 |
| 2020 | 23 | 29 |
| 2021 | 21 | 31 |
| 2022 | 20 | 21 |
| 2023 | 27 | 26 |
| 2024 | 30 | 25 |
| 2025 | 21 | 18 |
| 2026 | 13 | 11 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- HV apparatus and a method of manufacturing such apparatus15 Sep 2026US 12,738,415 B2Hitachi Energy Ltd
- Current transformer polarity verification15 Sep 2026US 12,738,416 B2Google Inc.
- Current transformer with improved performance18 Aug 2026US 12,712,123 B2Arbiter Systems, Incorporated
- Photovoltaic converter and photovoltaic generation system28 Jul 2026US 12,695,027 B2Huawei Digital Power Technologies Co., Ltd.
- Current sensing device23 Jun 2026US 12,663,443 B2ABB Schweiz AG
- Current transformer polarity verification24 Sep 2026US 2026/0290685 A1Google Inc.
- Busway plug-in device13 Aug 2026US 2026/0237948 A1Taiwan Busway Co., Ltd.
- System on sensor electrical protective device30 Jul 2026US 2026/0221365 A1Schneider Electric USA, Inc.
- Power supply unit and circuit breaker30 Jul 2026US 2026/0221758 A1Eaton Intelligent Power Limited
- Current sensor and measurement device23 Jul 2026US 2026/0211007 A1Hioki E. E. Corporation
Most cited
By later US patents
- Split core sensing transformer254US 7,312,686 B2Veris Industries, LLC · 2007
- Adjustable overhead conductor monitoring device191US 9,368,275 B2Cooper Technologies Company · 2016
- Portable self powered line mountable device for measuring and transmitting ambient temperature191US 9,380,857 B22016
- Supplemental electrical power generating system115US 4,262,209 A1981
- Revenue meter with integral current transformer102US 6,064,192 AOhio Semitronics · 2000