Nuckolls OVM-14 Mk III (Rev 1d, Apr 2025)
author: Eric
2 layer board of 2.23 x 0.70 inches (56.7 x 17.8 mm)
Uploaded:
April 02, 2025
Shared:
April 08, 2025
Total Price:
$7.80
Description: This board is for the “OVM-14 Mk III” Overvoltage Protection Module designed by Robert L. Nuckolls III, as posted to the AeroElectric-List forum. There have been minor changes made to this version, as detailed in the project documentation (see below).
This board provides overvoltage protection for the charging system in an Experimental category aircraft. It’s a “crowbar” type circuit, which is intended to blow a fuse or circuit breaker in the alternator field supply or to open a relay in the AC feed from a permanent magnet stator.
The nominal trip voltages are 16.0V in normal mode and 13.7V in maintenance test mode (both values subject to 1% resistor tolerance). The design is tested and working; see performance on the last page of the documentation PDF.
This project is intended for use in Experimental category aircraft only. Do NOT install it in a CAR Part 3 or FAR Part 23 certificated aircraft without FAA Field Approval.
BOM: Cost is ~$14 for the components to populate this board. Click for a Digi-Key saved list with those parts.
Download: Click here for a .ZIP archive containing full documentation in PDF format, DipTrace v5.1.0.3 CAD files and RS-274X Gerber files.
Description: This board is for the “OVM-14 Mk III” Overvoltage Protection Module designed by Robert L. Nuckolls III, as posted to the AeroElectric-List forum. There have been minor changes made to this version, as detailed in the project documentation (see below).
This board provides overvoltage protection for the charging system in an Experimental category aircraft. It’s a “crowbar” type circuit, which is intended to blow a fuse or circuit breaker in the alternator field supply or to open a relay in the AC feed from a permanent magnet stator.
The nominal trip voltages are 16.0V in normal mode and 13.7V in maintenance test mode (both values subject to 1% resistor tolerance). The design is tested and working; see performance on the last page of the documentation PDF.
This project is intended for use in Experimental category aircraft only. Do NOT install it in a CAR Part 3 or FAR Part 23 certificated aircraft without FAA Field Approval.
BOM: Cost is ~$14 for the components to populate this board. Click for a Digi-Key saved list with those parts.
Download: Click here for a .ZIP archive containing full documentation in PDF format, DipTrace v5.1.0.3 CAD files and RS-274X Gerber files.
