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  #31  
Old 03-21-2018, 02:19 PM
rv7charlie rv7charlie is offline
 
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Location: Pocahontas MS
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Originally Posted by Phantom30 View Post
I thought about going this route; however, what concerned me was when a regulator goes south...there is always a chance it could wreck havoc on “very expensive electronics”....just a thought🤓
That *shouldn't* be an issue in a properly designed electrical system.


(aeroelectric connection...aeroelectric connection...aero.....)
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  #32  
Old 03-21-2018, 02:43 PM
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Phantom30 Phantom30 is offline
 
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Quote:
Originally Posted by rv7charlie View Post
That *shouldn't* be an issue in a properly designed electrical system.


(aeroelectric connection...aeroelectric connection...aero.....)
I guess “shoudn’t“ does not make me feel warm and fuzzy! I’ve seen first hand what run-away charging systems can do...this is an area where saving a few bucks doesn’t make sense to me....but, hey. We are all big boys....follow your own gut on this issue.
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Tho RVN)
Distinguished Flying Cross Society Member
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RV-12 Kit#729 "N312RD" is now a full functioning fun machine!! Thanks Van for fulfilling my dream😎
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  #33  
Old 03-21-2018, 03:15 PM
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DaleB DaleB is offline
 
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Location: Omaha, NE (KMLE)
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Quote:
Originally Posted by rv7charlie View Post
That *shouldn't* be an issue in a properly designed electrical system.


(aeroelectric connection...aeroelectric connection...aero.....)
That assumes an electrical system different from the Rotax/RV-12, I think.

The Rotax doesn't use an alternator with a field winding, so you can't "crowbar" the field winding and shut down the alternator if there's an overvoltage condition. The rectifier/voltage regulator is the only thing other than the switch that stands between the raw output of the alternator and your avionics. One of the possible failure modes (we don't know how likely) would be full or partial rectification, with no regulation at all. It is possible for the regulator to fail in a manner that would put a fairly high voltage onto the bus. I know when my $30 Amazon special clone of the Deere regulator went south (after roughly 6 hours), my Dynon told me the bus voltage was 16V. I suspect it was higher, but had no real instrumentation on board.

Fortunately the D180, GTX 327, GPS 496 and SL 40 are all designed for voltages in excess of 30V. I'd be a little concerned about the fuel pump if the overvoltage condition lasted more than a few minutes.

I personally won't go back to that style of regulator because I have little to no confidence that they won't fail at random and possibly short intervals. The smell of electrical smoke and alarms going off in flight do not inspire confidence among my passengers.
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Omaha, NE
RV-12 # 222 N980KM "Screamin' Canary" (bought flying)
Fisher Celebrity (under construction)
Previous RV-7 project (sold)
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  #34  
Old 03-21-2018, 03:54 PM
Dave12 Dave12 is offline
 
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I have had 6 failures in two different 12’s and in each case, the failure was at start up. It seems to me that the voltage did go to about 19 volts or so. Same exact scenario with the Ducati and Amazon. Doesn’t seem that one holds up any better than the other. The Amazon does get hotter.
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  #35  
Old 03-21-2018, 04:19 PM
rv7charlie rv7charlie is offline
 
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Arrrgggg.......

Aeroelectric. Aeroelectric. Aeroelectric. ...

Come on, guys. The dynamo that's being sold by B&C, etc is the same *type* of permanent magnet generator as what you're getting on a 912. If your -12 is a factory-built light sport, I guess you're out of luck. But if it's got 'experimental' anywhere in its name, you can fix the problem of overvoltage risk. If you're flying a Lyc with one of those PM backup generators, you're at the same risk as the Rotax guys and you need OV protection there, too.

To be explicit: Yes, overvoltage events can and quite likely will occur. Your mission, should you choose to accept it, is to wire your plane so an overvoltage event can't kill your electronics.

Aeroelectric. Aeroelectric.

Sign up for the aeroelectric list, and ask your question on how to solve the problem. You'll get referred to...wait for it...the Aeroelectric Connection book, which you can get for the effort of downloading it.

Charlie
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  #36  
Old 03-21-2018, 04:29 PM
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Phantom30 Phantom30 is offline
 
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Quote:
Originally Posted by rv7charlie View Post
Arrrgggg.......

Aeroelectric. Aeroelectric. Aeroelectric. ...

Come on, guys. The dynamo that's being sold by B&C, etc is the same *type* of permanent magnet generator as what you're getting on a 912. If your -12 is a factory-built light sport, I guess you're out of luck. But if it's got 'experimental' anywhere in its name, you can fix the problem of overvoltage risk. If you're flying a Lyc with one of those PM backup generators, you're at the same risk as the Rotax guys and you need OV protection there, too.

To be explicit: Yes, overvoltage events can and quite likely will occur. Your mission, should you choose to accept it, is to wire your plane so an overvoltage event can't kill your electronics.

Aeroelectric. Aeroelectric.

Sign up for the aeroelectric list, and ask your question on how to solve the problem. You'll get referred to...wait for it...the Aeroelectric Connection book, which you can get for the effort of downloading it.

Charlie
I’m confused......so I can install something else to protect my electrical system?

Why not just install a “quality built” “stepped charge rate” regulator/rectifier SH voltage regulator.....that solves both issues (lifi battery)...
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307 (CAB) Phantom
Search and Destroy (Can
Tho RVN)
Distinguished Flying Cross Society Member
CH-47 & UH-1H "Driver"
Rotax 9 Series Service IRMT

RV-12 Kit#729 "N312RD" is now a full functioning fun machine!! Thanks Van for fulfilling my dream😎
2018 Dues Paid
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  #37  
Old 03-21-2018, 05:42 PM
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DaleB DaleB is offline
 
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Originally Posted by Phantom30 View Post
I’m confused......so I can install something else to protect my electrical system?
In theory...

You could add a relay to disconnect your alternator from the rest of the system, and a fuse or breaker for that relay's coil, and a "crowbar" overvoltage module. Now you have added some more protection from overvoltage...

and three more potential points of failure (the fuse or breaker, OVP module, and the relay). Two of those will have at least two failure modes, one of which (each) you wouldn't know about until it's too late. You gain some degree of protection but introduce complexity and additional potential points of failure.

Isn't this fun?

So we know the Ducati regulator, or at least some number of them, and at least in the RV-12, has a reputation for failing somewhat more often than we'd like. It seems from what I have seen that most of the failures are the result of somewhat less than stellar quality design and manufacturing of the regulators.

Some have tried substituting a much, much cheaper regulator, with mixed success. Some have switched to the Silent Hektik regulators, and so far I don't think we've heard of any of those that have failed - but it's early in the game yet. The one thing I don't think we've heard yet is, "Hey, my regulator failed and took out my Dynon and Garmin stuff". I don't know what the chances are of that happening. I do know I'm not inclined to make even more extensive changes to a system that may have a reputation for eating voltage regulators, but does not seem to have developed an appetite for avionics.

That's just me. If you're flying an E-SLA or E-AB, feel free to go your own way.
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  #38  
Old 03-21-2018, 06:43 PM
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tomkk tomkk is offline
 
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Quote:
Originally Posted by Phantom30 View Post
I’m confused......so I can install something else to protect my electrical system?

Why not just install a “quality built” “stepped charge rate” regulator/rectifier SH voltage regulator.....that solves both issues (lifi battery)...
... because the last I knew they were a bit hard to come by here in the States. Has that changed?
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  #39  
Old 03-21-2018, 07:50 PM
RFSchaller RFSchaller is offline
 
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I’m tempting the electrical gods here, but V/R failure has not been a huge problem for me. I replaced one at about 300 Hours based on a low voltage alarm after start. I now have 400 hours on the second Ducati and it seems happy here in the Phoenix heat. Cracking of the ignition coil bracket is a much bigger PITA for me.
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  #40  
Old 03-21-2018, 08:24 PM
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Phantom30 Phantom30 is offline
 
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Originally Posted by tomkk View Post
... because the last I knew they were a bit hard to come by here in the States. Has that changed?
They can be ordered through motorcycle shops in the UK...motoguzi shop sent me mine.
__________________
Ric Dickison
307 (CAB) Phantom
Search and Destroy (Can
Tho RVN)
Distinguished Flying Cross Society Member
CH-47 & UH-1H "Driver"
Rotax 9 Series Service IRMT

RV-12 Kit#729 "N312RD" is now a full functioning fun machine!! Thanks Van for fulfilling my dream😎
2018 Dues Paid
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