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  #1  
Old 07-16-2017, 01:34 PM
istrumit's Avatar
istrumit istrumit is offline
 
Join Date: Nov 2015
Location: Franklin, TN
Posts: 190
Default Never talk down an issue

I've had a few issues in the last few weeks.

A main bus voltage reading low/zero and an oil pressure reading dropping out.

The local avionics shop cleaned some pins and all was normal.

So. On my way back from a weekend flight out of town, I started hearing a persistent whine in my headset. Out of curiosity I flipped over to the engine monitoring page and both bus voltages were out of range high. Off scale.

Then I started smelling something hot, very hot.

I turned off the master and pulled all the breakers.

Landed nearest which was about 7 long minutes.

I don't know what I have to fix, but it's sitting in kind strangers hangar until it's fixed.

Lesson learned. Never fly with a mystery reading.
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  #2  
Old 07-16-2017, 02:19 PM
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Default

On a ground run, test voltages and turn on/off alternator field(s) to see what may be going on. You could have a bad voltage regulator.
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  #3  
Old 07-16-2017, 02:31 PM
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RV7A Flyer RV7A Flyer is offline
 
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Location: US
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Default

Quote:
Originally Posted by istrumit View Post
I've had a few issues in the last few weeks.

A main bus voltage reading low/zero and an oil pressure reading dropping out.

The local avionics shop cleaned some pins and all was normal.

So. On my way back from a weekend flight out of town, I started hearing a persistent whine in my headset. Out of curiosity I flipped over to the engine monitoring page and both bus voltages were out of range high. Off scale.

Then I started smelling something hot, very hot.

I turned off the master and pulled all the breakers.

Landed nearest which was about 7 long minutes.

I don't know what I have to fix, but it's sitting in kind strangers hangar until it's fixed.

Lesson learned. Never fly with a mystery reading.
Which EFIS/EMS do you have? Does it have configurable alarm settings for high/low voltage or amps?

As for the suggestion to turn off/on the alternator during ground checks...it's your call, but considerable anecdotal evidence on this forum indicates that's hard on an alternator after the engine is running (I start with mine on, and it stays on until the engine is shut down). Loads, yes...alternator, perhaps not.
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  #4  
Old 07-16-2017, 02:38 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 1,998
Default Alternator

What kind of alternator. Single or dual?? Plane Power in theory overvoltage protection should have shut off alternator. Did you damage any avionics??
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  #5  
Old 07-17-2017, 08:42 AM
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istrumit istrumit is offline
 
Join Date: Nov 2015
Location: Franklin, TN
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Default

To answer several questions at once:

I have a field breaker on the breaker panel, so I am assuming that means I have an external regulator.

I have only one alternator. It briefly stopped working after the event, but then started working again.

During ground test, the voltage was normal, but briefly spiked on a test around the pattern.

The Lightspeed ignition is non-working. There is no breaker for this on the breaker panel. I am hoping there is one somewhere else.

I have a G900X panel built by Stein in 2007. I have contacted them.

There are two 28V feeds to the G900X via a voltage step up system. The breaker for one of the feeds is popped (permanently) and the breaker for my Sorcerer is popped (permanently).

Everything in the G900X works except the Com/Nav down stream of the popped 28V breaker. I am hopeful that the step up is the only thing burned out and that the Com/Nav are fine downstream.

Everything else works except the Autopilot and the Lightspeed.

I also burned out the iPhone chargers stuck in the cig adapters.

Basically, a huge over voltage situation in which, if there is OV protection, it did not work. Had I had two electronic ignitions, I would have experienced engine failure.
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  #6  
Old 07-17-2017, 09:00 AM
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Auburntsts Auburntsts is offline
 
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Location: Dumfries, VA
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Default

Quote:
Originally Posted by istrumit View Post
To answer several questions at once:

I have a field breaker on the breaker panel, so I am assuming that means I have an external regulator.

I have only one alternator. It briefly stopped working after the event, but then started working again.

During ground test, the voltage was normal, but briefly spiked on a test around the pattern.

The Lightspeed ignition is non-working. There is no breaker for this on the breaker panel. I am hoping there is one somewhere else.

I have a G900X panel built by Stein in 2007. I have contacted them.

There are two 28V feeds to the G900X via a voltage step up system. The breaker for one of the feeds is popped (permanently) and the breaker for my Sorcerer is popped (permanently).

Everything in the G900X works except the Com/Nav down stream of the popped 28V breaker. I am hopeful that the step up is the only thing burned out and that the Com/Nav are fine downstream.

Everything else works except the Autopilot and the Lightspeed.

I also burned out the iPhone chargers stuck in the cig adapters.

Basically, a huge over voltage situation in which, if there is OV protection, it did not work. Had I had two electronic ignitions, I would have experienced engine failure.
The field breaker applies to both externally and internally regulated alternators. What's the alternator brand? B&C is going to be external whereas a PlanePower could be either (differentiated by EI or EE in the model number).
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  #7  
Old 07-17-2017, 09:05 AM
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JonJay JonJay is offline
 
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Location: Battleground
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Default

Scott - thanks for posting your issues for others.
A Field Breaker will be present regardless of internal or external regulated.
Stien is great and will be your best resource.
I would encourage you to get more familiar with your electrical system, as I am sure you will. This is one area of huge variances in experimental aircraft.
Good job managing things and getting yourself safely down.
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  #8  
Old 07-17-2017, 10:45 AM
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istrumit istrumit is offline
 
Join Date: Nov 2015
Location: Franklin, TN
Posts: 190
Default

After speaking with Stein, he feels its going to be a failed regulator in an older alternator that does not have internal OV protection.

Replacing the alternator should prevent this from ever happening again.

Most likely, that evolving failure was the reason for my intermittent under-volt.

So, I just need to get a new alternator and figure out how to get my light speed to work. That will get me home and I can solve the Sorcerer later.
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  #9  
Old 07-17-2017, 11:02 AM
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istrumit istrumit is offline
 
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Location: Franklin, TN
Posts: 190
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If anyone out there has a Light Speed Ignition system and put in a breaker for it, where did you install it ?

There is no breaker in my breaker panel.

Perhaps it is located somewhere else ?

I am hoping the LS just needs a breaker reset, rather than removed and sent to Klaus.
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  #10  
Old 07-17-2017, 11:35 AM
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airguy airguy is offline
 
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Location: Garden City, Tx
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Default

Check your power leads from the Lightspeed box to the power bus, you may have a fuse holder in place somewhere behind the panel with a blown fuse.
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