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Alternator, Regulator, Inter Av, Plane Power


211º

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I have been searching for a resolution to an issue. About 50 hours ago, my alternator on my E went out - that is fine, things happen.  I replaced the alternator yesterday and flew home - everything seemed to work fine (so that is good). 

But on the flight home, I (self)-noticed that I have a little anxiety about the JPI showing the voltage fluctuating between about 13.4 to about 14.1 (which is an improvement as it used to fluctuate between 12.4 and 13.1. But after having to divert last week while watching the voltage decrease from about 13.1 to 12.8 and then drop off to 11.2, I'd prefer to not have that happen again.

In working with the mechanic in Columbia MO, he was able to find a hand drawn matrix troubleshooting sheet (Link 1 below includes the Inter Av version before their website went off line). This document also has trouble showing tips - similar to the Zefronics Troubleshooting guide (Item 3) that has been linked a few times on MooneySpace.

I've also linked a ton of mooneyspace posts regarding alternators, regulators, Inter Av, Plane Power, etc.

I am going to run more diagnosis on my bird as I think that a good bandaid has been applied, but I'm not 100% confident on the fix just yet. I have several issues to resolve:

  • My iPad connect to a Garmin GTX 345 to get its flight data. On my last flight home, my ground speed fluctuated 10-15 knots for about 30 min (I'll add a screen shot in a little bit).  About once every three flights, I get a notification that my 345 has disconnected from my iPad - but when I switch to "devices" on my iPad the connection is there - perhaps it is a quick disconnect and reconnect (?) related to voltage?
  • After landing, there was a large buzzing in the overhead speaker that would start and stop when turning on/off Comm 1 (I forget the comm model)
  • When using Comm 1, ATC has reported that it sounds like I'm in a helicopter (and when I pull the radio's switch out (is it a auto squelch switch?) I can hear the flopflopflop audio and/or static.

My hope is to fix this issue, but also to corral much of the recent alternator talk into one post... and also with a resolution

  1. Inter Av Trouble Shooting Guide, Voltage Matrix, and Wiring Diagram - Uploaded to Mooneyspace Nov 16, 2019
  2. Troubleshooting Alternator by AlexLev - Oct 18, 2019
  3. Zefronics Troubleshooting Guide - mentioned in several posts
  4. Alternator Charging by Alex F - Oct 12, 2019 - 
  5. Alternator by Jkeeen02 - July 6, 2019 - Voltage readings from 13.5 - 14.7v
  6. Alternator not putting out by Pitch June 21, 2019 
  7. Low Voltage - battery or alternator by MICKEY May 6, 2019
  8. Electric grimlins - alternator by BaldEagle (with summary resolution) April 14, 2019
  9. Alternator is not charging by battery by Janat83 (with summary resolution) January 19, 2019
  10. Alternator problems by Philip Dec 28, 2018 
  11. Inter Av Installation directions
  12. Inter Av Alternator Conversion Troubleshooting by danb35 in 2014
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Here is a screen shot from ForeFlight after the completion of the flight.  As I'm looking at it again, it appears that there is a frequency to this as well - I'll see if I can determine the frequency to see if that offers any additional clues.

IMG_7449.jpg

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I zoomed in on my iPad. Is there anything in an airplane that happens about every 10 seconds? For these spikes to occur, it would seem that the 345 would need to lose "or fall behind" its position about every 10 seconds. At this portion of the flight, strobes were off. 

Spike Sequence.png

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7 minutes ago, ArtVandelay said:

Lose/bad field wire or ground connection on the voltage regulator end would be my guess, or it’s bad. Carefully inspect the wires and connectors, get a 2nd voltage regulator.
 

Yep, I like the way that you're thinking. I didn't download the JPI info last evening, but am going to go get that data to see the trending of the voltages. -Dave

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I went down a similar path that you did. I made a cross country flight and saw my voltage drop from 13.8 to 13.0 and periodically to 12.9. At my destination, the shop thought it was the alternator and I had them replace the alternator with a Plane Power. The check out showed the voltage at 13.8 to 13.9. On the flight home my voltage started dropping again.

Went through all of the wiring and followed the troubleshooting guides for both Zeftronics and Plane Power. Everything pointed to the regulator. Replaced the regulator with a Zeftronics and the voltage has been a rock solid 14.1 since.




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I had low voltage as well.  VR circuit breaker and low field wire voltage caused by old (original?) master switch.  Which VR do you have??  Digital or old mechanical?

Bottom line, on a 50 year old electrical system, you’re building resistance on worn wires, circuit breakers, switches.  You’re gonna have to dig in with a voltmeter and the Zeftronics troubleshooting guide to find it.

Do you have the electrical schematic?  Did you know your field wire leaves the VR, goes to your master switch and then back to your alternator?

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Did you have the Interav rebuilt or buy another?  The Interav system (Motorola) is set up different from most other charging systems.  The Internav voltage is always on the low side and varies a fair amount with load.  So, what do you have now?

A rebuilt Inter Av is installed now. The “helicopter noise” on Comm 1 is a concern as I’m wondering if it is a precursor to a future failure. (It started about 8 hours before the diversion. Maybe it’s a coincidence that the radio and alternator both went bad together... but I’d prefer some type of conclusive closure.


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Also, I think a better way to check the 345 would be to run a free adsb report from the faa.  I’m pretty sure that would tell you if it was missing reports/data.

My thought with the 345 isn’t that I’m missing transmitting data - I was being tracked IFR during the flight - to me it is the possibility that the 345 went off line for just a little while (1.5 seconds) and during that time didn’t capture gps location so that when it came back on, I was father away and so it calculated the higher ground speed (the spikes at 10 sec intervals on ForeFlight).

I’m trying to figure out if the 345 is getting a high or low voltage that kicks it off line for 1.5 sec every 10 sec. and what ever has a 10 sec freq might be holding the smoking gun.

Right now, I’m wondering if the inter account regulator has some type of 6 time per minute process.


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6 minutes ago, 211º said:


My thought with the 345 isn’t that I’m missing transmitting data - I was being tracked IFR during the flight - to me it is the possibility that the 345 went off line for just a little while (1.5 seconds) and during that time didn’t capture gps location so that when it came back on, I was father away and so it calculated the higher ground speed (the spikes at 10 sec intervals on ForeFlight).

I’m trying to figure out if the 345 is getting a high or low voltage that kicks it off line for 1.5 sec every 10 sec. and what ever has a 10 sec freq might be holding the smoking gun.

Right now, I’m wondering if the inter account regulator has some type of 6 time per minute process.


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Yeah, I see what you’re looking for, but I’m pretty sure the 345 is transmitting multiple times per second, we can probably look that up.  Anyway, if it was really offline or losing position each few seconds, you’d probably have a pretty ugly adsb report.

I have no doubt you’ve got an electrical issue, but I doubt that airspeed/345 plot is gonna help you diagnose it.  I could certainly be wrong, but I think you’re gonna have to get a voltmeter into all the connections to find the culprit.

Which kind of VR do you have?

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27 minutes ago, 211º said:

And I just realized that the JPI is set to collet its data every 10 seconds - 6 times a minute.

 

Not that this will help you with your issue, but The JPI factory default is every 6 sec - 10x a min. Most of the 700 series will go as fast as every 2 sec (some really old ones will not) 800 series and up will support every sec which is what I would recommend for a more useful finer data resolution. 

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The Zeftronics guide is a little tough to follow until you just do it.  After working through it, seeing what you’re looking for gets much easier.

As David mentioned, the interav may react a bit differently with voltages so the zef guide may not be perfect, but in it’s simplest form:

1. Turn on master

2. Check battery voltage at the battery terminal (i.e. on the battery itself)

3. Check voltage into the Voltage Reg - if it’s 0.5V or greater LESS than battery voltage, work backwards, find out where the drop is and fix it.

4. Check field voltage out of the VR.  (This should be less than battery, around 10-11 volts or so).

5. Check field voltage at alternator - shouldn’t have more than 0.5V drop from #4.

6. Turn off master and analyze.

Anyway, read the Zeftronics troubleshooting guide.  That's the gist of it and it’s not too hard.

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Not that this will help you with your issue, but The JPI factory default is every 6 sec - 10x a min. Most of the 700 series will go as fast as every 2 sec (some really old ones will not) 800 series and up will support every sec which is what I would recommend for a more useful finer data resolution. 

When I set it to 1 second on my JPI 900, it messed up by GPS ground speed (made them negative), so I put it back to 2 not knowing if other data was corrupted.
09d8b7037556de3a9a4f5c9e3fce630a.jpg



Tom
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9 hours ago, Ragsf15e said:

The Zeftronics guide is a little tough to follow until you just do it.  After working through it, seeing what you’re looking for gets much easier.

That is a great summary - maybe I can find time between chores today to get down to the hangar. This list causes me to wonder about fluctuating voltages while static on the ground - within the master and avionics switches on, the JPI will sometimes start at 12.5v and then vary down to 11.8v - without any apparent loads induced into the system.

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13.8V is the charging spec.   Lots of it depends on where your volt meter is measuring from.    Idea would have it on the terminal posts of the battery.   So the B+ lead that supplies the CB panel would be the best point to measure without running wire to the back of the plane.  Some of the fluctuation could be based on what other components are connected to the measuring point.

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13 minutes ago, Yetti said:

13.8V is the charging spec.   Lots of it depends on where your volt meter is measuring from.    Idea would have it on the terminal posts of the battery.   So the B+ lead that supplies the CB panel would be the best point to measure without running wire to the back of the plane.  Some of the fluctuation could be based on what other components are connected to the measuring point.

True.  Also, when you flip on the master, you’re likely seeing a “top charge” that’s higher due to the alternator charging (during last flight) at some voltage higher than the battery spec.  It’ll drop down a bit in the first couple minutes with some draw.  It should then settle close to 12v at the battery.  Remember, the JPI is measuring voltage somewhere else (bus), so you’ve got to measure at different points through the system and find where your voltage is dropping.

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9 hours ago, ArtVandelay said:


When I set it to 1 second on my JPI 900, it messed up by GPS ground speed (made them negative), so I put it back to 2 not knowing if other data was corrupted.

Tom

I see hundreds of JPI 900/930's working fine at the 1 sec data resolution - its what we recommend to all our clients. Something is wrong or not right and I would recommend contacting JPI technical support to get this fixed. 

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