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Never talk down an issue

istrumit

Well Known Member
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.
 
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.
 
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.
 
Alternator

What kind of alternator. Single or dual?? Plane Power in theory overvoltage protection should have shut off alternator. Did you damage any avionics??
 
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.
 
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).
 
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.
 
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.
 
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.
 
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.
 
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
 
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".
 
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.
 
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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.
 
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.
 
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).
 
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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.
 
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.
 
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.
 
2. I need to have over voltage alarms on my EIS, not just under voltage.

This should be a good little notice to go through the entire EIS and check ALL alarms - limits, type (latching/non-latching), annunciation (visual and/or aural), etc. Amps, volts, pressures, temperatures, RPM...check them all.
 
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.

Standard as supplied 60A ND in Vans kits and Auto Parts store. Standard wiring schematic from Vans.
The OP stated that he has a Field Breaker which he assumed must be a remote regulator. A couple of us noted that internal regulated may also have separate field wire.
This has always been the standard for the 60A alternators. Perhaps something is getting lost in translation? I have changed out several of them.
 
As for the light speed, it should be power from the battery to the breaker to the switch to the box. That's it. That way with the master off or failed you still get protected power o the box.

Bob burns
Rv-4 N82rb
 
Standard as supplied 60A ND in Vans kits and Auto Parts store. Standard wiring schematic from Vans.
The OP stated that he has a Field Breaker which he assumed must be a remote regulator. A couple of us noted that internal regulated may also have separate field wire.
This has always been the standard for the 60A alternators. Perhaps something is getting lost in translation? I have changed out several of them.
I need to see the ND model number, or at least the Lester number. All the internally regulated models I'm familiar with require positive voltage on the IG terminal to *start* the alternator's output, but most of the older ones will continue to operate with the IG terminal floating (voltage removed) after start of output. Some newer models can be turned off using the IG terminal, but this is *not* a field terminal. It's a control terminal, and if the regulator fails, it may or may not respond to the control signal on the IG terminal. The S (sense) terminal simply allows remote measurement of voltage, but connection isn't required for proper operation of the alternator.

What *internally regulated* ND models have you seen with actual field wires brought out to the connector terminals? How are the terminals labeled?

edit: When you say the one Van's supplies, are you talking about this?
http://www.vansaircraft.com/cgi-bin/store.cgi?ident=1500337790-354-642&browse=engines&product=alternator-kit

If so, I strongly suspect that you will get very different functionality if you replace a Plane Power model with a similar looking ND from an auto parts house.
 
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I need to see the ND model number, or at least the Lester number. All the internally regulated models I'm familiar with require positive voltage on the IG terminal to *start* the alternator's output, but most of the older ones will continue to operate with the IG terminal floating (voltage removed) after start of output. Some newer models can be turned off using the IG terminal, but this is *not* a field terminal. It's a control terminal, and if the regulator fails, it may or may not respond to the control signal on the IG terminal. The S (sense) terminal simply allows remote measurement of voltage, but connection isn't required for proper operation of the alternator.

What *internally regulated* ND models have you seen with actual field wires brought out to the connector terminals? How are the terminals labeled?

I am out of town but I will dig up one of my old ND's. It may we'll be a "control" input, but when switched off, at anytime, running or not, the alternator quits charging. You may very well be correct in that a regulator failure may lend the control input useless. Doesn't matter. We where simply trying to let the OP know that just because he has a switch labeled Alt. or Field doesn't mean it is a remote regulator. Mine isn't and never has been.
It does lend one to think if the purpose of the Alt. Field switch is to remove a bad behaving alternator from the system, if it fails in a way that doesn't allow that, the switch is useless.
 
Sorry, I didn't see your edit. My original Vans unit was an ND. I replaced it with with a Plane Power and it behaves exactly the same.
 
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I look forward to getting the model number of the ones you're using, because as I said, if ND makes a model with internal regulation *and* an interrupt-able field winding, that will be great news. This stuff has been hashed out on the Aeroelectric list for a couple of decades, and all the models that anyone over there has ever found, require opening the alternator up, cutting traces on the regulator circuit board, re-wiring, and in most cases, drilling holes in the case to bring the field windings out for external positive control. All the models that can be 'controlled' by the IG terminal (that have been checked) by the guys who frequent the Aeroelectric list are known to be vulnerable to non-control of the field, if the regulator fails. The only way to positively control the field is to open the circuit, and if the internal regulator/OV module is supposed to do that, you're depending on silicon (which often fails shorted) to do a fuse/circuit breaker's job.
 
Whine in headset

While flying a rented 172 with my instructor at night - over LA, we heard a brief 'whine' in the headsets. Your situation is likely different but after we landed at an uncontrolled airport, my instructor found that the main power wire from the fwf to the cabin had shorted out on the metal firewall. Killed all electrical power - lights, radio, transponder, etc. Fun in the dark and no flaps for landing. Suggest that you a complete checkout of all wiring.
 
Charly - I don't doubt your experience. I can only report how mine functioned(s) when I throw the switch. Probably best to take this offline or start another discussion as we have drifted and are not helping the OP solve his issues. I will follow up privately as many okder kits may have the ND alternators wired to an Alt. switch with no modifications. That was the standard in the day. It sounds like they may not do anything for us when we need them most, like a run away if they don't have O/V protection, or if the OV protection fails like in this OP's example.
 
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