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  #1  
Old 08-29-2017, 06:48 PM
edward7048 edward7048 is offline
 
Join Date: May 2010
Location: Kokomo, In.
Posts: 91
Default regulator slow to come on line

On my last few startups my voltage shows battery voltage with no charge
after about 2 to 3 minutes the voltage jumps to the upper 13 volts
and is charging ok and this last for the hole flight. I am using the
original regulator mounted in the cabin and I my normal run up rpm is
2200 to2300 has anyone else had this problem?
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  #2  
Old 08-30-2017, 05:41 AM
BigJohn BigJohn is offline
 
Join Date: Nov 2008
Location: Gloversville, NY
Posts: 1,470
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Search the forum for previous threads on similar symptoms. This sounds like the classic pre-cursor to Ducati failure.
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  #3  
Old 08-30-2017, 11:01 AM
DHeal DHeal is offline
 
Join Date: Sep 2006
Location: Windsor, California
Posts: 612
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I am no electrical guru but here is my response based on my 540 hours of RV-12 operating time: The ROTAX 912 ULS uses an integrated AC generator with an external rectifier-regulator (aka "dynamo") to produce electrical energy for both the ignition system and the 12 volt DC airframe system. This "dynamo" produces power in much the same way as the "generators" of yore (i.e., low RPM produces low electrical power). At lower RPMs, I typically see low system voltage and negative amps -- depending on the accessories (e.g., lights, AP, etc.) in use at the time. At high RPMs, all appears to work well with 13.9 volts and 1 amp consistently being displayed. I have given up on trying to correlate electrical system readings beyond that stated above -- the voltage and amp readings vary a bit at other than high RPM settings.

ps -- I now have 410 hours on my relocated Ducati regulator/rectifier -- fingers crossed!!
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  #4  
Old 08-30-2017, 02:59 PM
WingedFrog's Avatar
WingedFrog WingedFrog is offline
 
Join Date: Mar 2010
Location: Raleigh, NC
Posts: 854
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Quote:
Originally Posted by edward7048 View Post
On my last few startups my voltage shows battery voltage with no charge
after about 2 to 3 minutes the voltage jumps to the upper 13 volts
and is charging ok and this last for the hole flight. I am using the
original regulator mounted in the cabin and I my normal run up rpm is
2200 to2300 has anyone else had this problem?
I had the same symptom before the failure of my Ducati regulator at less than a hundred hours. The deterioration of the solders on the SCR leads starts to show up on cold start. What you observe is not related to rpms but temperature. Once you push rpms a bit the increase of temp. in the regulator repairs the contact.
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Kit # 120395 N124BX
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Builder's Blog:http://vieilleburette.blogspot.com/
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