overvoltage/undervoltage relay modification

[jim plaster]

Prepping a Carbon Cub for installation of the new relay,wires and led. Looks like a simple install . Has anyone here done this mod yet? It looks like several instruments need to come out to locate the dc bus for the positive and ground bus as well. Any help would be appreciated. Had a picture sent of the ground bus ,but looks nothing like mine.

[jim plaster]

Just got done with the service letter on the installation. Pretty simple installation and works as advertised!

[Pete D]

Glad it went in easy for you!

The ground bus was a small change they did a while back to allow more connection points without having so many wires at each attachment point. Not a big change, just one of the many small tweaks to improve things as we go along.

[marcusadolfsson]

Been doing some research on the electrical schematics, and one thing that stands out in the post #294 AMM is the OV Relay / Crowbar for over-voltage protection. Was this made available as a retrofit? SI0024 is just a sensor, correct?

[marcusadolfsson]

Separately, the alternator field wire is on the earlier serials on the External Main Bus and was later moved to Main Bus. Was that because voltage was weakest on the External Bus, or because lack of breaker space?

[dayoung107]

Been doing some research ... Was this made available as a retrofit? SI0024 is just a sensor, correct?

Correct, SI0024 is just a sensor. The retrofit of the crowbar may be simple enough to request a Major Repair or Alteration (MRA). Please contact Jeff Glab, our customer service representative, if you would like to go this route. The MRA form can also be found on our website.

Separately, the alternator field wire is on the earlier serials on the External Main Bus and was later moved to Main Bus. Was that because voltage was weakest on the External Bus, or because lack of breaker space?

This is very much a breaker space issue. This aircraft is not really large enough to worry about voltage drops causing equipment not to function. But we do everything we can to squeeze breakers into the instrument panel.

Hope that helps,