Alternator over-voltage and trip... back to Battery Voltage...

Piper_Six

Piper_Six

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1959 Bonqnza K35
Just had my first in-flight "event" - All normal in flight, (1959 Bonanza K-35), happily cruising at 6500', and smooth as glass beautiful evening. The usual scan suddenly caught the voltage reading in yellow - flashing at 12.3 V and current showing a discharge 4.5 Amps... This is on a MVP-50 screen that is set up to show voltage and current draw at all times.

Figured at this time the alternator is not putting out any power and everything was running on battery. Started shutting down all the lights, extra radio, and eventually shut down the 430 as well. Nothing changed the voltage, now flashing yellow at 12.1 V. I have an electrically operated landing gear, and was considering dropping the gear and fly at gear down speed, rest of the way, had about 50 miles to go to my home base.

Shut the alternator switch to OFF, and ON again, the voltage showed a healthy green 13.5 V and a positive charging current 8-9-10 Amps... but this lasted only a few seconds, then back to a discharge and low voltage, back to 12.3, 12.2... and going down.

Just to be sure, pulled out the manual gear extension procedure and reviewed it... but didn't need to as the gear did extend correctly about 10 miles out...landed and while taxiing out to the hangar, again noticed the voltage back to 13.6V, 10A positive and all seemed fine, but only lasted a few minutes and then back...

Next day, came to the hangar and measured the voltage at the output of the alternator while engine ran, just showing battery voltage only... and a discharge.

Figured the alternator was shot, it was an older InterAV, 12V - found one at QAA, ordered it and replaced it today.

Everything seemed just fine - with the new alternator in place, voltage in green 13.8> volts, and a good charging current... but in just few minutes, things went strange... the voltage started to rise... 13, 14 , 15 and 16 V flashing in RED... and current draw was in the 4-6-8 Amp range fluctuating, no other loads at this time. Then suddenly, voltage back to battery voltage, discharge indication, and slowly dropping, and getting to 12.2, 12.1 volts, yellow and flashing, not charging...

Resetting the ALT and Master switch again seems to start fine and goes back to this condition, voltage rise and cut-ff...

Now suspecting the voltage regulator... have ordered one, will see if that was the issue.

Sharing to see if anyone has any thoughts/ideas/things I should be looking at or have had similar experience...

Here are some video of the above...






Thanks.
 
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When I had an overvoltage issue that caused the OV protection to shut down the alternator, I bought another regulator to replace what I believed was the problem. While doing so I discovered a connection that appeared to be getting warm. After a proper repair I've had no more concerns. I'd suggest that you possibly have a connection that is loose or corroded.
 
Hmmm, probably going to put that new voltage regulator in and tighten up the loose wire that's causing the issue, or not. I'd be looking at connections and wire for problems.
 
Do you have the accompanying Interav voltage regulator? It has been my experience that due to age they have become unreliable. Symptoms were similar, they worked for a while then went offline for one reason or another. I've tossed both of the regulators on the Cubs I fly and maintain in the garbage and replaced with Plane Power units. Hopefully they're good for another 30 years.

As mentioned above, connections are important and may also be causing trouble. Don't accept anything less than perfect.
 
Doing the farmer fix , throw parts at it till it works . ;)
 
First low voltage, then high...I'd suspect something in the field circuit, maybe a chafed wire, or bad OV relay or splice if it's the original Interav setup. Installing a Plane Power unit at this point is probably money well spent.
 
Thanks Chip... can you elaborate what you meant by "...or bad OV relay or splice ...", I get the OV relay, what is splice ? A loose ground wire ? Because, I DID find a loose, frayed ground strap, which I replaced, but didn't change anything.
 
Splice/crimp.
I've mentioned this before. Check the field wire and connector to the alternator. Vibration will occasionally cause the conductor to break within an intact insulator rendering the fault invisible. The intermittent nature of your charging circuit could be caused by an intermittent field voltage.
 
Check the voltage regulator connector, they are Probably simple slip-on contacts and it’s loose
 
Piper_Six said:
Thanks Chip... can you elaborate what you meant by "...or bad OV relay or splice ...", I get the OV relay, what is splice ? A loose ground wire ? Because, I DID find a loose, frayed ground strap, which I replaced, but didn't change anything.
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If you have an InterAv alternator, you have a Motorola voltage regulator and an overvolt relay spliced into the field wire from the alternator, as well as a humungous capacitor that provides spike protection. If the system was installed per the original STC, the relay gets it's supply voltage from a breaker on the main bus. The overvolt relay in this system is notorious for going bad and fluctuating field voltage, the regulator itself is very heat sensitive, and all the splices and connections are prime corrosion targets. The OV relay itself is NLA.

The alternator itself is a solid unit.

I chased my intermittent low voltage for a little bit and came to the conclusion that for a little over $200, it's worth it to just yank all that Mickey mouse crap out and go with a Plane Power with integrated overvolt protection. Plane Power is the only solid state regulator stc'd to replace the InterAv stuff.
 
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One thing to mention, now that you have similar input from both Chip and myself regarding the regulator and over voltage relay - the wiring instructions that Plane Power provides to switch from the Interav regulator to the Plane Power one were terrible. I tried following it to be able to state that the PP regulator was installed IAW the manual but that wouldn’t have produced a workable result (at least on the late model Cubs). Make sure whomever is performing the work understands charging systems and can think for themselves rather than just following the directions.
 
mondtster said:
One thing to mention, now that you have similar input from both Chip and myself regarding the regulator and over voltage relay - the wiring instructions that Plane Power provides to switch from the Interav regulator to the Plane Power one were terrible. I tried following it to be able to state that the PP regulator was installed IAW the manual but that wouldn’t have produced a workable result (at least on the late model Cubs). Make sure whomever is performing the work understands charging systems and can think for themselves rather than just following the directions.
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Curious where yours went off the rails? My own problems were the result of the previous InterAv installer not following those instructions with proper breakers etc. If they had, the Plane Power install would have been a lot faster. Instead of an afternoon, it took an extra few hours, but everything's according to Hoyle now.

Other than a couple of nomenclature differences they don't explain well, I thought the IM was pretty clear. I hate it when installers "think for themselves". First you have to figure out what they did, then figure out how to make it right. If you do freelance, for the love of God make detailed drawings and put them in the documentation.
 
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mondtster said:
One thing to mention, now that you have similar input from both Chip and myself regarding the regulator and over voltage relay - the wiring instructions that Plane Power provides to switch from the Interav regulator to the Plane Power one were terrible. I tried following it to be able to state that the PP regulator was installed IAW the manual but that wouldn’t have produced a workable result (at least on the late model Cubs). Make sure whomever is performing the work understands charging systems and can think for themselves rather than just following the directions.
Click to expand...

Okay now you are scaring me ;) My A&P is a super nice guy but not sure if Electrical is his strong suit, just from my experience.
 
Chip Sylverne said:
Curious where yours went off the rails? My own problems were the result of the previous InterAv installer not following those instructions with proper breakers etc. If they had, the Plane Power install would have been a lot faster. Instead of an afternoon, it took an extra few hours, but everything's according to Hoyle now.

Other than a couple of nomenclature differences they don't explain well, I thought the IM was pretty clear. I hate it when installers "think for themselves". First you have to figure out what they did, then figure out how to make it right. If you do freelance, for the love of God make detailed drawings and put them in the documentation.
Click to expand...

Oh boy :) , it is going to be a fun few days ahead ;) Just don't want to "fry" anything in the process !
 
Chip Sylverne said:
Curious where yours went off the rails? My own problems were the result of the previous InterAv installer not following those instructions with proper breakers etc. If they had, the Plane Power install would have been a lot faster. Instead of an afternoon, it took an extra few hours, but everything's according to Hoyle now.

Other than a couple of nomenclature differences they don't explain well, I thought the IM was pretty clear. I hate it when installers "think for themselves". First you have to figure out what they did, then figure out how to make it right. If you do freelance, for the love of God make detailed drawings and put them in the documentation.
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In my case, both Interav installations were factory installed in late model Super Cubs and were wired as depicted in the Piper wiring diagram. The problem was with where Plane Power thought the power for the regulator In the Interav system was coming from. If you wired it as Plane Power instructed, the field circuit breaker did nothing and the alternator could not be disabled in an emergency. It was, in my opinion, completely unsafe and also did not conform to the generic regulator instructions that Plane Power also provided.

If the Interav specific Plane Power instructions are ignored and the generic Installation instructions followed, it will work as it should. Anybody with basic electrical knowledge will be able to figure it out but if the installer’s electrical expertise stops at reading the instructions and putting wire B on post A then hoping it works, they’re in for a challenge.
 
That's basically is what I found. In my case, power for the InterAv OV relay as installed came from an unprotected circuit, basically from the hot cable to the starter solenoid ( I say unprotected, but the 60 amp main breaker left the OV relay basically unprotected!). Had the installer done the work IAW the InterAv manual, juice would have come from a 5 amp breaker off the main bus. The Plane Power IM assumes the InterAv install was done according to the InterAv IM. Unfortunately the original installer left no clues, so the first hour or two was spent ringing wires to see what was what.
 
Well... BUMMER... replaced the voltage regulator with a new PP regulator and followed the instructions right... still doing the same thing ....

Still doing the same ... when I recycle the ALT on/off switch, it shows its charging.... draws a good amount of current, then cuts off the alternator and falls to batter voltage.... This is what it was doing before we replaced the alternator AND the voltage regulator... no idea where to go from here ... ?


Any thoughts ?

Thanks in advace.
 
Piper_Six said:
Well... BUMMER... replaced the voltage regulator with a new PP regulator and followed the instructions right... still doing the same thing ....

Still doing the same ... when I recycle the ALT on/off switch, it shows its charging.... draws a good amount of current, then cuts off the alternator and falls to batter voltage.... This is what it was doing before we replaced the alternator AND the voltage regulator... no idea where to go from here ... ?


Any thoughts ?

Thanks in advace.
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You need a wiring diagram and a volt/ohm meter. I would start at that switch. Throwing parts at it is getting you nowhere. Either trace it down yourself, or find someone with the skills.

Also, why is the left aux tank and other indicator flashing yellow? Could be related.

Here is a video I posted for another POAer who was having electrical issues. This is an auto mechanic and the problem was pretty simple, but the diagnosing procedure should be similar for your issue.

 
Thanks - yes the left aux tank is flashing yellow because it’s almost empty. The other yellow flashers are low oil temp, since it takes a good few minutes for that to turn green , usually by the time I get the weather and set up the iPad and such it’s green.

Yes, have the wiring diagram and visually it checks so far , now to start diagnosing electrically.

Oh one question: When I replaced the old InterAV alternator, with a new one (same make and model), it came with this label ... at first, when I only replaced the alternator, the Voltage regulator was still the InterAV... but now that is replaced with the new PP regulator. Do I need to remove the "excitement resistor" as stated on that card ? Since the regulator isn't an InterAV anymore? Could this be what's causing the issue ? I will check this tomorrow... wondering if anyone has any insight into this label / card .. attached below..
 

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The alternator needs a little voltage to get "excited" and start making juice. Usually somewhere in the neighborhood of 8-9v . That can come from the regulator aux post when the master is turned on, or via the excitement resistor. If you are using the aux post from the alternator to the regulator, you don't need it, but likely it wouldn't cause your problem.

The Plane Power has integral OV protection that pops the breaker connected to the enable post in an overvolt condition, cutting voltage from the field. Run a jumper from the field post to VOM and watch the field voltage when this cutout happens. Paul could be on to something, it could be your switch, as that also cuts enable voltage.

Look at the bright side, once you work this out you'll have a good solid alt and regulator!
 
PaulS said:
Do you have an overvoltage relay?
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The InterAv setup had to have come out when he installed the Plane Power. Plane Power has an excellent troubleshooting .pdf on it's website. I'd upload it, but can't seem to get anything but a .jpg to upload.
 
Chip Sylverne said:
The InterAv setup had to have come out when he installed the Plane Power. Plane Power has an excellent troubleshooting .pdf on it's website. I'd upload it, but can't seem to get anything but a .jpg to upload.
Click to expand...

Lol, beat me to it, they also have tech support , give them a call.

Here is the link to the trouble shooting pdf, but I really didn't see anything that would cause your issue there, wouldn't hurt to go through it, but it would be much easier to call them up.

https://planepower.aero/wp-content/...e-Engine-Externally-Regulated-Alternators.pdf
 
Thank you, will follow that troubleshooter guide to the Tee and see what I may find...
 
Piper_Six said:
Thank you, will follow that troubleshooter guide to the Tee and see what I may find...
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Suggest you give them a call too before you go back, could really save you a lot of time and money.
 
Update....

Yes, gave them a call, and they have been EXTREMELY helpful, got me on the phone while I was plane side, and walked me through a series of diagnostics, much in line with that document posted above, and finally, here is where we are at... the over voltage relay, which I thought was not present (as I hadn't seen it), was finally found.. it was buried way back behind the firewall, cabin side, securely mounted. It appears that the relay is faulty (open) - because there is no bus voltage on the "enable" wire at the regulator... So, this morning begins the task of tracing this wire all the way... and removing the OVR and figure out why there is no power at the ENABLE wire... So it continues... will keep y'all updated.
 
Excellent news, sounds like your problem is in that relay or it's connections. Good job!!! Keep us posted.
 
Suggest you use an ohm meter, disconnect the enable wire from the relay and alternator and check for continuity in the wire from relay to alternator, then confirm no continuity to ground. If both those test ok it's probably worth replacing the relay. Also check the relay ground and the wire to the relay coil for continuity or voltage while running if you really want to be safe.
 
Piper_Six said:
Update....

Yes, gave them a call, and they have been EXTREMELY helpful, got me on the phone while I was plane side, and walked me through a series of diagnostics, much in line with that document posted above, and finally, here is where we are at... the over voltage relay, which I thought was not present (as I hadn't seen it), was finally found.. it was buried way back behind the firewall, cabin side, securely mounted. It appears that the relay is faulty (open) - because there is no bus voltage on the "enable" wire at the regulator... So, this morning begins the task of tracing this wire all the way... and removing the OVR and figure out why there is no power at the ENABLE wire... So it continues... will keep y'all updated.
Click to expand...

If installed IAW the manual, the InterAv OV relay was spliced into the field wire, and powered by a line from a 5 amp main bus breaker. The OV relay has to be removed. The enable post on the PP regulator should be powered by the power cable that powered the OV relay, and the field wire at the relay spliced back together. The integrated OV protection in the PP regulator WILL NOT WORK unless the enable is powered by a circuit with 5 amp breaker. In the event of overvolt, the regulator pops that breaker to cut off field voltage.

You may find the Interav wasn't installed IAW the manual, mine wasn't.

Helps a lot if you read the install manual.
 
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PaulS said:
Suggest you use an ohm meter, disconnect the enable wire from the relay and alternator and check for continuity in the wire from relay to alternator, then confirm no continuity to ground. If both those test ok it's probably worth replacing the relay. Also check the relay ground and the wire to the relay coil for continuity or voltage while running if you really want to be safe.
Click to expand...

With the install of the Plane Power regulator, that relay has to come out. The Plane Power protects itself.
 
Chip Sylverne said:
If installed IAW the manual, the InterAv OV relay was spliced into the field wire, and powered by a line from a 5 amp main bus breaker. The OV relay has to be removed. The enable post on the PP regulator should be powered by the power cable that powered the OV relay, and the field wire at the relay spliced back together. The integrated OV protection in the PP regulator WILL NOT WORK unless the enable is powered by a circuit with 5 amp breaker. In the event of overvolt, the regulator pops that breaker to cut off field voltage.

You may find the InterAV wasn't installed IAW the manual, mine wasn't.

Helps a lot if you read the install manual.
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YES ! Lessons learned (and learning...) I was wrong to assume the OVR went away with the old INterAV regulator, I found the OVR buried close to the firewall inside the cabin, in front of the co-pilots seat... So THAT cold be a reason why no power at the enable wire. The OVR is NOT spliced in the FLD circuit.... in fact the Field terminal on the alternator is directly connected to the FLD terminal of the PP regulator. So it appears that the OVR was spliced into the wire that provides the enable voltage to the regulator.

I can barely access this OVR set up, but as you said, if I can connect the power line of this OVR to enable, and take the two green wires from the OVR and short them, that should possibly work?

The saga continues...

Thank you for the feedback/advice, very much appreciated.
 
Of the four wires connected to the Interav OVR, one will be 12v, one will be ground, one will be from the field of the alt, one will be to the field post on the regulator (otherwise, it did nothing and there was no point to it having been installed.) What I would do is take a VOM and identify which breaker provides the 12v, and confirm it's 5amp suitable for the PP enable post. If not, you'll have to install a suitable breaker. Then I would ring the green wires to see if they were properly spliced into the field wire. IF so, then yes, splicing the is the correct move IAW the Plane Power IM, but that would give you at least three splices in the field wire, the two original plus the new one,which is one tooo many IMHO.

I have a .pdf of the Interav IM that I would happily send you, if you want to see how the IntweAv should have been installed. Might be helpful. Shoot me an email addy if you want it.
 
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Thanks Chip, yes surely would like to see that PDF, as you say, the OVR should have been in the field circuit, but mine doesn't appear so, because there already is a direct wire between FLD of the PP regulator and the field post on the alternator, I pulled out both ends and checked continuity to be sure. So my guess is this OVR is in the enable circuit... Sent you an email. Thank you very much. Will let you know how this turns out, should be able to get there later today, dealing with a work crisis this morning!

My email addy is pipersix@gmail.com

Yes, used to have a Cherokee Six, then a Saratoga, and now a 1959 Bonanza K-35
Let me see how many will say "Should have kept the Toga" or the "Six" :)
 
Piper_Six said:
Thanks Chip, yes surely would like to see that PDF, as you say, the OVR should have been in the field circuit, but mine doesn't appear so, because there already is a direct wire between FLD of the PP regulator and the field post on the alternator, I pulled out both ends and checked continuity to be sure. So my guess is this OVR is in the enable circuit... Sent you an email. Thank you very much. Will let you know how this turns out, should be able to get there later today, dealing with a work crisis this morning!

My email addy is pipersix@gmail.com

Yes, used to have a Cherokee Six, then a Saratoga, and now a 1959 Bonanza K-35
Let me see how many will say "Should have kept the Toga" or the "Six" :)
Click to expand...

Something to be said for keeping the Lycoming. ;)

Just because the field wire has continuity, doesn't mean it doesn't also go through the OVR, unless you took it out of the circuit.

IM on it's way. Hope it helps.
 
Alternator woes.... continues.....

Made sure the wiring is done right, checked it a few times, and ensured all connections are good and secure and per the diagram. However, on starting, everything seemed fine, full 14.2 V and battery charging - however saw an excessive current draw with no other loads, no Radios, no lights nothing... it was upwards of 35Amps ! Voltage stabilized somewhat... but as RPM slowly increased - voltage increased and current draw also increased.... voltage went up to 15.2 and then cut off.... back to battery voltage with a discharge.... :(

So after all the wiring, rewiring and all... back to square one.... excessive current draw and rising voltage are main fault modes... then cut off...

Here is a video...


I have attached the old Inter AV set up (Thank you Chip for sending it, I also found the exact same in the books of the plane too), and the changes made for the new Plane Power regulator... both circuits...

I am at my wits end :( Guess there is possibly a chaffed wire causing a short somewhere... possible fixes/tests;

1. Rewire the field circuit wire with a NEW wire by pass all old wires
2. Possibly fried the PP regulator while testing with wrong wires ?
 

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If you have wired the PP regulator as per the drawn lines, it's not wired properly. The post labeled "Reg" on the InterAv alternator goes to the "aux" post on the PP regulator, and is a low volt "excite" signal that increases in voltage as the alternator starts to make juice. If you put a VOM on it at the alt with master on but engine off, you should see in the neighborhood of 8v. When the InterAv ( actually a Motorola) alternator was commonly used in boats and tractors, it is what those regulators used to light the "low volt " lights prior to start. Voltage just increases as rpm increases.

If you don't have low voltage annunciator lights, you don't even need to connect that post.

If your "Actual Sense" wire isn't protected by a 5amp breaker, you have no overvolt protection. For that reason your PP install manual says to jumper enable and sense posts, and power the the regulator via a protected circuit through the enable post. Wired the way you have, you could fry the regulator, and much more.

Wire it IAW the PP install manual, don't get creative.
 
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Chip Sylverne said:
If you have wired the PP regulator as per the drawn lines, it's not wired properly. The post labeled "Reg" on the InterAv alternator goes to the "aux" post on the PP regulator, and is a low volt "excite" signal that increases in voltage as the alternator starts to make juice. If you put a VOM on it at the alt with master on but engine off, you should see in the neighborhood of 8v. When the InterAv ( actually a Motorola) alternator was commonly used in boats and tractors, it is what those regulators used to light the "low volt " lights prior to start. Voltage just increases as rpm increases.

If you don't have low voltage annunciator lights, you don't even need to connect that post.

If your "Actual Sense" wire isn't protected by a 5amp breaker, you have no overvolt protection. For that reason your PP install manual says to jumper enable and sense posts, and power the the regulator via a protected circuit through the enable post. Wired the way you have, you could fry the regulator, and much more.

Wire it IAW the PP install manual, don't get creative.
Click to expand...


Thanks Chip, so... if the REG goes to AUX, and the SENSE and ENABLE are jumpered together, what goes into ENABLE terminal ?
 
Piper_Six said:
Thanks Chip, so... if the REG goes to AUX, and the SENSE and ENABLE are jumpered together, what goes into ENABLE terminal ?
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12v from a 5amp breaker on your main bus. If your InterAv was wired properly, you'll use the wire that powered the OVR after confirming the circuit is properly protected. If not, you'll need to install a 5 amp breaker, and run a wire to "enable" from that. The jumper is a short wire that goes from the enable post to the sense post on the regulator.
There should be a short jumper already made up that came in the box with the regulator.
 
Chip Sylverne said:
12v from a 5amp breaker on your main bus. If your InterAv was wired properly, you'll use the wire that powered the OVR after confirming the circuit is properly protected. If not, you'll need to install a 5 amp breaker, and run a wire to "enable" from that. The jumper is a short wire that goes from the enable post to the sense post on the regulator.
There should be a short jumper already made up that came in the box with the regulator.
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Ahh Yes I see where I went terribly wrong, in reading the R1224 install procedure I mis-read this note from the manual

"...Connect the ENABLE terminal to the regulator/field power source (the wire from the cockpit ALTERNATOR FIELD switch which is fed from a 7.5 max amp breaker)...."

I mis-read this to read ENABLE to REG on the alternator...

I can see how badly I screwed up !
 
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