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  #1  
Old 03-27-2015, 06:12 PM
jtrollin jtrollin is offline
 
Join Date: Aug 2008
Location: Leesburg, va
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Default Plane Power and VPX, Alternator shutting off

I am having an issue with my alternator where when watching it via the VPX screen on my G3X it shows the alternator turning off and then on again at random intervals. This is causing my battery to drain and create havoc with my systems not hooked up to my backup battery.

I have replaced the voltage regulator thinking that might be the problem, but no luck, same issue. Anyone have any ideas on what could be going on? I plan on taking my laptop out tomorrow so I can watch the VPX logs as it happens, but thought I would ask for some ideas.

thanks,
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  #2  
Old 03-27-2015, 06:49 PM
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Bill.Peyton Bill.Peyton is offline
 
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The plane power alternators that I am familiar with have a self contained voltage regulator. I assume you re watching the field current on the VPX. If that's the case, it is normal to see a fluctuation in the amount of current being drawn by the alternator field. If you post your schematic it would be easier to help you out.
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Old 03-27-2015, 06:54 PM
jtrollin jtrollin is offline
 
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Bill,

Let me see if I can get a image of my wiring, but I followed the VPX manual. It is not the current, the VPX shows the alternator go to a power off state, like I turned off the switch, then it comes back on again at random intervals.

John
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Old 03-27-2015, 07:06 PM
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Bill.Peyton Bill.Peyton is offline
 
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Which plane power alternator?
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Old 03-27-2015, 07:14 PM
jtrollin jtrollin is offline
 
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It is the one that comes with the firewall forward kit fro vans, think it's AL12-EI60

John
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http://websites.expercraft.com/jtrollin/
Phase 1 Complete
Vans Builder Number: 40923
798HJ Reserved
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  #6  
Old 03-27-2015, 07:17 PM
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Bill.Peyton Bill.Peyton is offline
 
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That alternator has the internal VR and OV crowbar. You stated you had replaced the voltage regulator, so I am a bit confused how you replaced the VR
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Old 03-27-2015, 07:19 PM
jtrollin jtrollin is offline
 
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They have a kit to replace it. They recommend it be replaced every so many hours, forgot the number. It was actually pretty easy to change out.
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RV-10
http://websites.expercraft.com/jtrollin/
Phase 1 Complete
Vans Builder Number: 40923
798HJ Reserved
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  #8  
Old 03-27-2015, 07:28 PM
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Bill.Peyton Bill.Peyton is offline
 
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I can't imagine why they would recommend periodic replacement of a functioning part. I assume everything worked at some point. I would suggest you put a voltmeter on the field connector at the alternator and verify you have around .3 volts less than the battery voltage. If so, I would run the engine without the avionics on, and check the voltage at the battery, it should be greater than 13.8 volts. At this point I would monitor the voltage output to see if it is rising above 16 volts, which is about where the crowbar over voltage will kick in. This should also fault your current on the VPX field circuit. One additional thing, could your belt be loose? How many hours do you have on the alternator? PP is real good with warranty issues, send it in and have it checked out.
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  #9  
Old 03-27-2015, 07:42 PM
jtrollin jtrollin is offline
 
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It has brushes on it that wear out over time. You are supposed to check the length of the brushes and replace if the are a certain size.
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RV-10
http://websites.expercraft.com/jtrollin/
Phase 1 Complete
Vans Builder Number: 40923
798HJ Reserved
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  #10  
Old 03-27-2015, 07:45 PM
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How many hours do you have on the alternator? I would think that it would not be unreasonable to expect 500 hours on the alternator without maintenance.
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