Samuel, This is a simple dynamo type charging system. The easiest thing to do in diagnostics is to break it down into it's simplest parts. So the question becomes, is this a problem with the dynamo? Is it the regulator (rectifier set)? Or is it the wiring? First off, let me say that I have never touched a Revmaster or other VW charging system. But have repaired similar type of dynamo charging systems on Jabirus, motorcycles and outboard boat engines. The only difference being that those systems are full wave where the Revmaster apparently only uses a half wave rectifier.
So, let's start with the dynamo. You'll note the dynamo itself has no ground when it is not plugged into the regulator. So, unplug the dynamo (alternator) from the regulator, then using your meter in continuity mode, test the two leads coming from the dynamo against ground. They should not be grounded. If they are, there is a problem there. Then test for continuity through the dynamo from one lead to the other. That should show continuity looking nearly like a dead short between the leads. If those tests are both good, your dynamo is probably good. Assuming the dynamo is good, now we test the regulator. The "regulator" in this case is not a regulator at all, but instead is a half wave bridge rectifier. That means that it uses a pair of diodes to filter the AC current coming from the dynamo into pulsed DC. The simple way to test this is to disconnect it from the circuit. Using your meter in continuity mode again, test for continuity between the red and yellow poles as shown on the drawing you referenced. Reverse the leads and check again. You should see continuity in one direct, and no continuity in the other. If that's the case, then the diodes are good and the half bridge should be functional. That only leaves the wiring to sort out. In the drawing you referenced, I see one glaring issue that I can't seem to rectify in my head. The "yellow loop" appears to connect 12V DC directly to one leg of the stator, which is producing unregulated AC. That would be unlike any dynamo I have ever seen and I wouldn't think that would work. In fact, it should trip the breaker. It likely trips the breaker any time that circuit is energized whether the engine is running or not. When the engine is running, the two wires coming from the stator should be producing unregulated variable frequency AC voltage. I would think feeding that directly to the battery would be a problem. I can not find a drawing of the TMG-3096 regulator on line, but every rectifier/regulator I have seen has a minimum of either 4 leads, or 3 leads and a mounting tab that is used for ground. Typically the two leads from the stator connect to two leads on the regulator for A/C input(there is no polarity since they are not grounded and produce A/C voltage), and the other two leads are the output with a nominal 12 - 14V DC on one lead and the other lead being the ground reference for the system (or may be grounded through a mounting tab). I'll be happy to help you diagnose it a bit further if you want, but a good photo of your regulator and accurate description of the regulator wiring and actual model would be helpful. But let's do it off line, and you can post the final results once you have it working. -Jeff Scott Arkansas Ozarks --------------------- > Sent: Friday, May 22, 2020 at 1:12 AM > From: "Samuel Spanovich via KRnet" <[email protected]> > To: [email protected] > Cc: "Samuel Spanovich" <[email protected]> > Subject: KR> In need of some electrical help - Revmaster 2100D > > Guys, I stand before you a very very confused individual, and am really > hoping somebody might have a solution to help me get this bird back in the > air. > > After installing the engine back in N6399U (after my rebuild), I started her > up, and then noticed my alternator circuit breaker popped. When the engine > is running, and the alternator OFF, the voltage is a steady 12V, which makes > sense. However with the alternator ON (even with the engine completely off > OFF), the voltage will drop to about 8-10V, and eventually the circuit > breaker will pop again. I was thinking maybe the regulator/Rectifier was > short circuiting itself somehow, however after ordering a new one and > installing it exactly the same as the old one, the problem still persists. > > When removing the engine for my rebuild, other than disconnecting the wires > leading from the alternator to the regulator/Rectifier, I disconnected > NOTHING ELSE in terms of wiring. Now all of a sudden, after hooking > everything back up exactly as before, as soon as I turn the alternator switch > on (again, even with the engine off), in a matter of about 10 seconds, the > circuit breaker pops. > > There is obviously a short circuit somewhere, hence the voltage drop/circuit > breaker popping but I honestly am not sure where to even start looking. I > have my plane set up per Revmaster Alternator diagram (posted below). I’ve > noticed on the diagram that it says to ground the rectifier to the 12VDC > battery Ground, but this still is not doing the trick. I’ve also tried > grounding it in a different location, and with different wires as well, all > with the same results (circuit breaker popping). > > I will say....referencing the Revmaster alternator diagram, if I ONLY connect > the battery (hot wire) to the regulator/rectifier, the voltage will remain > steady. It’s only whenever I connect the alternator leads to the > rectifier/regulator as well, is when I notice the voltage drop. > > If somebody has a working Revmaster engine, would you mind taking a picture > of your rectifier/regulator setup, and also taking a picture of your grounds, > and also show me where your hot wire leads to, etc.? Now that I have taken > my old one out, and attempted to put my new one in, I no longer have a > working model of what the actual physical setup is supposed to look like. > > Also, does anybody know how you can actually test the alternator WITHOUT > taking it off the engine case (measuring resistance, volts AC coming out of > the leads with engine running, etc.). I’m really hoping the physical > alternator is not the problem, because if so, that fix that involves removing > the engine....again. > > Any help would be GREATLY appreciated! > > Revmaster diagram posted in this forum, about 1/2 way down. > http://forums.matronics.com/viewtopic.php?p=451960 > > V/R > > Sam Spanovich > N6399U > 74S, Anacortes WA > > Sent from my iPhone > _______________________________________________ > Search the KRnet Archives at > https://www.mail-archive.com/[email protected]/. > Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options. > To UNsubscribe from KRnet, send a message to [email protected] > _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/[email protected]/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to [email protected]
