Variable frequency generator and starter generator patents: who holds the claim space now
61.4% concentration. The top five assignees together hold 890 of the 1,449 records in scope — 61.4% of the field — with the leader alone accounting for 552. Annual filings climbed to 154 in 2018 before settling into a lower band; the 2021-to-2024 window shows a 27% decline (41 to 30), the last span both years of which are far enough past the cut-off to be treated as complete.
- 1HAMILTON SUNDSTRAND CORP552
- 2HONEYWELL INTERNATIONAL INC105
- 3SUNDSTRAND CORP90
- 4GE AVIATION SYSTEMS LLC72
- 5THE BOEING CO71
See the full variable frequency generators and starter generators analysis in Eureka
- The complete ranking, not just the top five
- Every IPC branch with its share of the corpus
- The most-cited records, and where claim space is still thin
Common questions about this landscape
Who holds the most patents on variable frequency and starter generators for aircraft?
The field is highly concentrated: the top five assignees together hold 890 of the 1,449 records in scope, 61.4% of the total, and the single leading assignee accounts for 552 of those on its own. This is typical of aerospace power electronics, where a small number of primes and their historical subsidiaries have filed continuously since well before this dataset's 2015 start. A new entrant should expect to be filing around, not into, open space held by these portfolios.
Is patent filing in this space growing or slowing?
Filings peaked at 154 in 2018 and have since eased; from 2021 (41) to 2024 (30), the last year that can be treated as complete, volume fell 27%. Because publication lags filing by roughly 18 months, 2025 and 2026 figures in any raw chart will look artificially low and should not be read as a continuation of the decline. The honest read is a maturing claim space rather than a shrinking one — high filing density in earlier years already occupies much of the core architecture.
What technology areas get the most patent claims in this field?
Control-related claims lead: IPC class H02P (control of motors and generators) covers 32.4% of the 1,449 records, narrowly ahead of H02K (electric motors and generators themselves) at 29.7%. Gas-turbine plant integration (F02C) and engine starting (F02N) follow at 17.9% and 12.8%. Because records often carry multiple IPC codes, these percentages overlap rather than sum to 100%, but the ordering is a reasonable proxy for where recent claim activity is densest.
Disclaimer. This analysis is based on Patsnap Eureka data drawn from a limited snapshot of global patent records and is provided for general information and reference only. Patent data carries inherent limitations — recent filings are under-counted because of publication lag, counts may be on a record or family basis, classification and applicant-name data may contain errors or duplicates, and the underlying search query defines the scope shown — so the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing here is an exhaustive prior-art, novelty, freedom-to-operate or validity search, nor does it constitute legal, financial or professional advice, and it should not be relied upon as such. Verify independently and review with qualified patent and legal professionals before acting on it.
Method: Filing trend and technology composition. Derived from a Patsnap search on Variable Frequency Generators and Starter Generators covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish. Every share divides by all records in scope. Data: Patsnap Eureka. See the full landscape report.