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Old 02-13-2019, 12:37 AM
isosceles isosceles is online now
Join Date: Jan 2018
Location: Fremont
Posts: 20

I have not removed it yet... Flying on the battery only for now. Planning on removing it in a coupe of weeks and have a look.
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Old 02-13-2019, 06:04 AM
Kalibr Kalibr is offline
Join Date: Aug 2015
Location: St John, Steamboat Springs, planet Earth generally
Posts: 51

Gents, the subject of this topic is the SD-8 alternator voltage regulator — a totally different beast than the L2\3 regulators mentioned in some of the posts. It has no built in OV protection, etc. The permanent magnet voltage regulator is not compatible with a field controllled alternator and vice versa. And I am pretty sure there is no aircraft-proprietary magic in that regulator. It looks, smells, works exactly the same as any other permanent magnet alternator voltage regulator. The SD-8 alternator itself in its core has a regular $40-80 tractor alternator. What makes it a $600 aircraft alternator is that is simply how high of a price the market can bear in the absence of competition — nothing wrong with that if you believe in freedom. On the other hand, there is nothing wrong with educating yourself, applying yourself, experimenting, etc.

Regarding failures, i hear the permanent magnet alt voltage regulators can get very hot and need good cooling (more so than the field controlling variety). Mounting it on the cold side of the firewall on a surface that provides good heat sink and good airflow helps with their longetivity.
Building a Panther, but lurking here, like many others

Last edited by Kalibr : 02-13-2019 at 06:23 AM.
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Old 02-13-2019, 05:53 PM
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sprucemoose sprucemoose is offline
Join Date: Jan 2005
Location: MKE
Posts: 1,503

Kalibr beat me to it but he is right- the the PM regulator/ rectifier does not contain crowbar OV protection like the LR-3 does. It is cheaply and easily added via parts available from B&C, and highly recommended.

A couple of years ago Nathan told me that they had a "new and improved" PM R/R in the works. You might check with him on that, but even a brand new old one is not terribly expensive.
Jeff Point
RV-6, RLU-1 built & flying
Tech Counselor, Flight Advisor & President, EAA Chapter 18
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