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  #11  
Old 07-17-2017, 01:05 PM
rv7charlie rv7charlie is online now
 
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Guys, please be careful when you 'help'. If he has an automotive style internally regulated alternator, and it's not been modified in some way, there is no 'field breaker'. Unmodified internally regulated alternators do not bring the field winding outside the alternator for external control of the field. Even then, there are other ways to protect the system from an overvoltage event, though.

If the voltage is going from low to normal to high and back, There's obviously a regulation issue. It could be the regulator itself (whether internal or external), or it could be wiring issues around the regulator circuit.

It's somewhat suspicious that there was low voltage until someone worked on the system, and then there was overvoltage. I'm guessing that istrumit didn't build the plane; did the builder supply a wiring diagram for it?

Charlie
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  #12  
Old 07-17-2017, 01:52 PM
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I have detailed build books. I will review tonight.

There is no regulator box on the firewall.
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  #13  
Old 07-17-2017, 01:55 PM
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Quote:
Originally Posted by rv7charlie View Post
Guys, please be careful when you 'help'. If he has an automotive style internally regulated alternator, and it's not been modified in some way, there is no 'field breaker'. Unmodified internally regulated alternators do not bring the field winding outside the alternator for external control of the field. Even then, there are other ways to protect the system from an overvoltage event, though.

If the voltage is going from low to normal to high and back, There's obviously a regulation issue. It could be the regulator itself (whether internal or external), or it could be wiring issues around the regulator circuit.

It's somewhat suspicious that there was low voltage until someone worked on the system, and then there was overvoltage. I'm guessing that istrumit didn't build the plane; did the builder supply a wiring diagram for it?

Charlie
Sort of true. The modification, like in an off the shelf Nippo Denso you get at any auto parts store, has the field jumped at the plug. So, the only "modification" is how you wire the plug.
I could understand if the "help" was something that might cause some safety issue or concern, but this is about as benign as it gets.
As with anything posted here, "trust and verify".
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  #14  
Old 07-17-2017, 02:53 PM
rv7charlie rv7charlie is online now
 
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Can you show me a model that does that? I've never seen one.
edit: I'm running an ND on my -4 now, & have more on the shelf for the -7, and I've had quite a few others. I'd love to find one wired that way; it would make controlling them much simpler.

Last edited by rv7charlie : 07-17-2017 at 02:55 PM.
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  #15  
Old 07-17-2017, 03:14 PM
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I plan to purchase the Plane Power AL12-EI7.

Its internally regulated, like the one I have now...and it has OV, which my dead one does not.


It will go on a Penn Yan IO540-DA45. If there is anything I need to know or modify before I purchase, based on your experience, please let me know.

Also, I'll be ordering replacement LightSpeed parts.
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  #16  
Old 07-17-2017, 04:02 PM
rv8ch rv8ch is offline
 
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Default old alternator

Hi Scott, Can you take a lot of pictures of your old alternator? It would be very interesting to know what kind it is. Thanks.
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  #17  
Old 07-17-2017, 04:19 PM
rv7charlie rv7charlie is online now
 
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Just looked at the Plane Power wiring graphic (didn't dig any deeper than that). No doubt it will work wired the way they show it (it's their product, after all), but you can get a cleaner, lighter, more reliable install with the B-lead wired through a fusible link to the load side of the master contactor.

If you're not really up on all things electrical, wire it exactly as they draw it. At least then they can't blame you if it dies. But I'd insist that they explain exactly how they implement their OV protection. The drawing of the alternator field enable circuit is...interesting. Ask for an actual schematic, including switch details, instead of the cartoon drawing.

If you don't have a copy of Bob Nuckoll's Aeroelectric Connection, I'd strongly recommend it. You can buy a printed copy, or download the latest version for free. It's a great training tool, and you can learn enough to get a lot more comfortable with a/c wiring 'stuff'.

As a FWIW, very few people have automatic OV protection, unless they either bought the B&C alternator/regulator, or they intentionally crafted something for themselves.

Charlie

edit: Just looked at their product page again. They spec the alternator system as 14 +/- .3volts. It will likely run a bit over 14V (most auto style systems do these days), but if it runs 14-.3 (13.7V), you'll have a relatively short lived AGM battery (PC680 or similar).

Last edited by rv7charlie : 07-17-2017 at 04:23 PM.
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  #18  
Old 07-17-2017, 04:45 PM
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Quote:
Originally Posted by rv8ch View Post
Hi Scott, Can you take a lot of pictures of your old alternator? It would be very interesting to know what kind it is. Thanks.
You bet...once I get it off of there. Gonna be a while to arrange everything (parts, manpower, etc...) since the plane is grounded 4.5 car hours away.
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  #19  
Old 07-17-2017, 04:52 PM
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istrumit istrumit is offline
 
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A couple of things that I keep going over in my head about this situation.

1. I heard a small whine on the radio...no big deal. I was bored and I am always sensitive to any changes...so, I did a little trouble shooting. What if I hadn't ? In all, less than 60 seconds went by between hearing something funny in the radio and shutting down the electrical system. In the last ten seconds of that minute, I smelled something burning. So, 50 seconds between over voltage and fumes. That "ain't" a lot of time.

2. I need to have over voltage alarms on my EIS, not just under voltage.

3. I love my Light Speed ignition. When folks talk about having two of them and no mechanical or pmag, most discussions I see are about what happens when you lose electrical power. For those that are connected to the bus, these usually becomes a discussion about redundancy, minimum battery life, etc. I have yet to see a discussion about what if I have a run away voltage situation and burn out BOTH ignitions. Something to think about.

4. Who woulda thought even the oldest alternators would normally fail high ? That seems like a pretty basic flaw. Oh well. I'm getting a new one built with OV.
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  #20  
Old 07-17-2017, 05:05 PM
rv7charlie rv7charlie is online now
 
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They don't normally fail high. I've had quite a few fail over the years, between the many cars and the few a/c I've owned, and none ever failed high, even when I was the reason they failed.

The golden BB just found yours. Stuff doesn't happen all the time, but sometimes it does.

The whine you heard could have been one or more of the rectifier diodes in the alternator failing. They usually fail open, and all you get is the whine. But on rare occasions, they fail shorted, and if there's not enough load to fry them open after that, you'll get the negative swings from the alternator into your regulator (and if your luck is bad enough, into your avionics). At any rate, the regulator obviously failed shorted (also rare, but it happens), and that's what started the death spiral for the rest of your avionics. The whine you heard could have been simply the unclamped voltage peaks from the alternator, after the regulator went into runaway mode.
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