H01F 29/00
Variable transformers or inductances not covered by group h01f21/00
Official title: Variable transformers or inductances not covered by group H01F21/00 {(tap change devices H01H9/0005)}
H01F29/00 (Variable transformers or inductances not covered by group h01f21/00) appears on 858 US grants and 638 published applications in this corpus.
Search patents in H01F- Granted patents
- 858
- Published applications
- 638
- Assignees
- 454
- Inventors
- 1,584
- Latest grant
- 6 Oct 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 20 | 0 |
| 1977 | 24 | 0 |
| 1978 | 17 | 0 |
| 1979 | 17 | 0 |
| 1980 | 17 | 0 |
| 1981 | 13 | 0 |
| 1982 | 13 | 0 |
| 1983 | 12 | 0 |
| 1984 | 11 | 0 |
| 1985 | 14 | 0 |
| 1986 | 9 | 0 |
| 1987 | 7 | 0 |
| 1988 | 9 | 0 |
| 1989 | 7 | 0 |
| 1990 | 7 | 0 |
| 1991 | 5 | 0 |
| 1992 | 7 | 0 |
| 1993 | 3 | 0 |
| 1994 | 11 | 0 |
| 1995 | 8 | 0 |
| 1996 | 12 | 0 |
| 1997 | 8 | 0 |
| 1998 | 15 | 0 |
| 1999 | 14 | 0 |
| 2000 | 17 | 0 |
| 2001 | 13 | 8 |
| 2002 | 19 | 29 |
| 2003 | 20 | 14 |
| 2004 | 17 | 25 |
| 2005 | 21 | 23 |
| 2006 | 19 | 19 |
| 2007 | 23 | 19 |
| 2008 | 19 | 21 |
| 2009 | 11 | 28 |
| 2010 | 13 | 18 |
| 2011 | 16 | 16 |
| 2012 | 23 | 13 |
| 2013 | 18 | 38 |
| 2014 | 24 | 40 |
| 2015 | 24 | 31 |
| 2016 | 27 | 32 |
| 2017 | 31 | 40 |
| 2018 | 38 | 31 |
| 2019 | 36 | 35 |
| 2020 | 37 | 28 |
| 2021 | 27 | 23 |
| 2022 | 16 | 21 |
| 2023 | 18 | 34 |
| 2024 | 20 | 19 |
| 2025 | 18 | 19 |
| 2026 | 13 | 14 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
- H01F 29/02Variable transformers or inductances not covered by group h01f21/00: with tappings on382
- H01F 29/14Variable transformers or inductances not covered by group h01f21/00: with variable magnetic329
- H01F 29/08Variable transformers or inductances not covered by group h01f21/00: with core, coil108
- H01F 29/06Variable transformers or inductances not covered by group h01f21/00: with current collector21
Recent patents
- Monitoring a transformer comprising a tap changer6 Oct 2026US 12,754,255 B2Hitachi Energy Ltd
- Transformer-hybrid variable reactance6 Oct 2026US 12,754,576 B2Clark Power Systems, Inc.
- Method and device for changing a transformation ratio, an impedance, or a voltage used for excitation6 Oct 2026US 12,756,193 B2Reinhausen GmbH
- Tap changer and a transformer arrangement comprising the tap changer29 Sep 2026US 12,749,618 B2Hitachi Energy Ltd
- On-load tap changer and tap-changing transformer having an on-load tap changer29 Sep 2026US 12,749,634 B2Maschinenfabrik Reinhausen GmbH
- Device Having a Multimode Antenna With Variable Width of Conductive Wire17 Sep 2026US 2026/0279661 A1NuCurrent, Inc.
- Voltage amplitude and phase adjustment apparatus and method, and computer device and storage medium27 Aug 2026US 2026/0254344 A1
- Method for producing an electrical regulation winding, prefabricated conductor arrangement and electric regulation winding16 Jul 2026US 2026/0204475 A1Hitachi Energy Ltd
- Ac powered nano-processor11 Jun 2026US 2026/0161208 A1PI Invent Inc.
- Three-dimensional vertical inductors with magnetic core11 Jun 2026US 2026/0162861 A1Microchip Technology Incorporated
Most cited
By later US patents
- Vacuum processing chamber having multi-mode access485US 6,095,083 AApplied Materiels, Inc. · 2000
- Planar transformer power supply266US 7,502,234 B2Aaron Medical Industries, Inc. · 2009
- Silicon scavenger in an inductively coupled RF plasma reactor249US 5,556,501 AAPPLIED Materials.Inc. · 1996
- Integrated-magnetic apparatus210US 5,726,615 A1998
- High power battery powered RF amplifier topology200US 10,159,524 B2Ethicon, Inc. · 2018