Rectifier regulator wiring harness problem update

[Ausflyer]

I have been ground running my all-but completed -12, and cannot get a positive amps reading on the dynon, and the voltage hovers around 12.

I went thru the paperwork and searched this forum and came up with DONT POWER-UP YOUR SYSTEM issue from September 09. Vans fix for this was Service Letter Sept 11, 2009. When building the FWF section I checked the revised plan sheet date and revision (45.05 rev 1 dated 09/08/09) and concluded at the time that this sheet revision must have included changes to overcome the regulator burnout problem. The coincidence of the Service Letter and the revised plan was plain. Now I'm not so sure. The revised plan still shows the Yellow wire going to the C terminal on the plug that goes into the regulator.

Eighteen months down the track its hard to believe Vans have no provided an ammended plan sheet to save new builders falling into this trap. How many regulators do they replace each month?

And its a clear safety issue too. As reported in the posts on this subject, the yellow wire is hot and has no fuse.

Tomorrow I plan to take my regulator to the local Ducati shop for testing. It failed my testing per Step 7 of the service letter, but I'm not that confident of my testing. Hopefully it's something simple I wired up wrong.



Rod

 

[Mich48041]

Regulator wiring

The Van's Service Bulletin dealt with a yellow wire going to terminal "L" on the voltage regulator. If your harness does not have a wire going to terminal "L", then the Service Bulletin does not concern you. A yellow wire SHOULD go to terminal "C". It is true that this yellow wire is not protected by a fuse and is connected directly to the battery through the master switch and battery contactor. A builder could double insulate the yellow wire where it passes through the firewall.
The "C" terminal on the regulator stands for Control. There must be voltage on the yellow wire to enable the regulator to work. With the master switch turned on, measure the voltage between ground and terminal "C". That voltage should be about the same as the battery voltage. If there is no voltage at terminal "C", then the problem is in the aircraft wiring, not the regulator. The firewall should not be painted under the voltage regulator in order to provide good electrical contact between the regulator and ground.
With the engine running, if there is battery voltage on regulator terminal "C" but no charging voltage output on terminals "B" and "R", then check the AC voltage coming from the alternator. Measure the AC voltage between the yellow wires (NOT to ground) on regulator terminals "G" and "G". If there is no AC voltage, then the alternator is at fault. If there is AC voltage of about 16 volts or more, then the alternator is working and the regulator must be at fault if it is not putting out more than 13 vdc on terminals "B" and "R".
Joe

 

[Mich48041]

RV-12 ammeter

By the way, do NOT pay much attention to the Dynon ammeter in the RV-12. It is pretty much useless. The way the aircraft is wired, the ammeter shows current going into or out of the battery, not current used by aircraft loads. A fully charged battery will have very little current going into it. A small charging current of 1 amp or less will probably not even show up on the Dynon 60 amp ammeter.
Joe

 

[Ausflyer]

Thanks Joe for your comprehensive explanation. I will head off to the AP and run the tests you suggest. I did not paint the firewall, but will check all the earths. Perhaps with a second look I can sort out if the Service letter applies to my kit.

 

[Ausflyer]

After a very frustrating day, the regulator problems seem to have resolved themselves. I now have Amps and Volts that increase with the engine rpm, and the voltage across the bettery when the master and ignition switches are off is holding (at least for a few hours). Tomorrow mornings startup will be interesting.

Thanks again Joe. I didn't have to go far down your list of tests to get a result.I still find the relevance of the Service Letter obscure to say the least. I understand that it must stay there. but builders would be helped if its application to which kits and plan sheets was clearer.

One thing I did learn was that Ducati motorcycles have nothing to do with Ducati electrics. The bikes have used Jap electrics since the 90's.

 

[Mich48041]

Intermittent problem?

Ausflyer,
It is unclear from your posting whether you found a problem and fixed it or if things just started working on their own. If it is an intermittent problem, then there could be a loose connection someplace. If you determine the cause of the low voltage, post your findings to help others.

I still find the relevance of the Service Letter obscure to say the least.

That Service Bulletin only applied to the first few kits. I am sure that Van's corrected the problem quickly because it cost them money to replace voltage regulators. Sometimes it seems that the plans or notices were written for lawyers instead of for laymen. But they have to be specific in every detail or else we would be making even more mistakes.
Joe