---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 09/12/25: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:11 AM - Re: Jabiru Alternator (dj_theis) 2. 11:05 AM - Re: Jabiru Alternator (user9253) 3. 12:06 PM - Re: Jabiru Alternator (dj_theis) 4. 12:46 PM - Re: Jabiru Alternator (user9253) 5. 12:47 PM - Re: Jabiru Alternator (dj_theis) 6. 02:26 PM - Re: Re: Jabiru Alternator (Rob Turk) ________________________________ Message 1 _____________________________________ Time: 07:11:58 AM PST US Subject: AeroElectric-List: Re: Jabiru Alternator From: "dj_theis" Hi Sebastien, Ive never worked on the Jabiru alternator but have spent countless hours on a similar integrated alternator on the Revmaster. Both are 12 pole permanent magnet (PM) anlternators and suffer from similar design and manufacturing shortcomings. Without going into any detail of the design or manufacturing flaws, if you are lucky the problem is your regulator /rectifier. If the problem extends to the stator, you might want to consider the available upgrade to an external field controlled alternator. https://www.rotecaerosport.com/alternatorupgrade I believe Jabiru stators are wound with 12 series wound (single phase) coils. If this is what you have there will be 2 wires coming from the alternator, likely leading to a relay. I dont know if Jabiru used an isolating relay between the stator and the regulator, can you provide a wiring diagram? There are a few things you can check. 1) Measure the resistance from wire to wire of the two output wires from the alternator stator, disconnected from the relay. These are the wires that should come directly from the stator and should be isolated from ground and have a measurable resistance (I dont know the specification for stator resistance on the Jabiru but you will need a good DVOM that can measure single digit resistance). Knowing the expected resistance is important as one of the common failures is a breakdown of the insulation on the stator wires and the resistance will be (significantly) less than the spec. Also check if there is an inline fuse in the stator wiring that could be blown. 2) Check that the alternator stator wires are isolated from ground. 3) Check that the relay (if it exists) is operational. (disconnected from the alternator and the regulator, energize the relay and verify that there is continuity between the contacts that were wired to one stator lead and one regulator lead. 4) Assuming the above tests dont expose a problem Testing the AC output of the alternator is a little more difficult but can be done. You will need to carefully wire and secure connections from the output of the alternator (the two stator wires) without the regulator, to an AC meter and run the engine from idle to the normal charge voltage. At idle (900 rpm) I would expect the voltage (AC rms) is well below the minimum charging voltage of 12.8 volts (note that it is the peak voltage, not the rms voltage that must rise above 12.8, and the rms underrepresents the peak by a multiple of about 1.4) Increasing the rpm should show an increase the voltage linearly, (if the voltage shows 9 volts at 900 rpm you should see something close to 18 volts at 1800 rpmdouble the rpm should double the open circuit voltage). You are measuring open circuit voltage (no load) and the connected voltage to a battery would be significantly less. So restating, doubling the rpm should double the open circuit voltage AC rms voltage. The open circuit voltage of a working PM alternator at moderate speeds will be astonishingly high! 20 volts (or more) is not uncommon when not connected to a battery at high rpm. 5) The rectifier/regulator is the last item to check and requires a capable bench AC source to do properly test but if all the above tests dont expose an obvious problem, you should have a working charging system that pretty much identifies the regulator as the point of failure. I hope this helps give you a little insight into what you might check. Dan Theis. -------- Dan Theis Scratch building Sonex #1362 Revmaster Alternator problem solved. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=515620#515620 ________________________________ Message 2 _____________________________________ Time: 11:05:04 AM PST US Subject: AeroElectric-List: Re: Jabiru Alternator From: "user9253" One way to check a rectifier/voltage regulator is to substitute a new one. if the new one works, then the old one must be bad. Search eBay for AM101406 which is for John Deere tractors. They sell for as little as $18, item number 176962600707. AM101406 has 5 terminals. B+ : Battery AC: Generator AC: Generator L: Lamp IGW: Ignition switch -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=515621#515621 ________________________________ Message 3 _____________________________________ Time: 12:06:19 PM PST US Subject: AeroElectric-List: Re: Jabiru Alternator From: "dj_theis" I second Joes suggestion. Ive tested the JD rectifier/regulator and found them to be good substitutes for whatever OEM R/R are supplied (single phase PMs only, of course). The only caution might be that these R/R devices have been on the market for a while and there might be less than ideal copies available. Purchasing from John Deere (or a reliable substitute provider), as Joe implies with the JD part number, is generally a reliable source. -------- Dan Theis Scratch building Sonex #1362 Revmaster Alternator problem solved. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=515622#515622 ________________________________ Message 4 _____________________________________ Time: 12:46:49 PM PST US Subject: AeroElectric-List: Re: Jabiru Alternator From: "user9253" The eBay item I suggested is not a genuine John Deere part. It is probably made in China. I have been using a similar voltage regulator in my RV-12 for 100s of hours without a problem. It is very important to keep the voltage regulator cool. Mount it using heat conductive paste and cool it with forced air. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=515623#515623 ________________________________ Message 5 _____________________________________ Time: 12:47:15 PM PST US Subject: AeroElectric-List: Re: Jabiru Alternator From: "dj_theis" I second Joes suggestion. Ive tested the JD rectifier/regulator and found them to be good substitutes for whatever OEM R/R are supplied (single phase PMs only, of course). The only caution might be that these R/R devices have been on the market for a while and there might be less than ideal copies available. Purchasing from John Deere (or a reliable substitute provider), as Joe implies with the JD part number, is generally a reliable source. -------- Dan Theis Scratch building Sonex #1362 Revmaster Alternator problem solved. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=515624#515624 ________________________________ Message 6 _____________________________________ Time: 02:26:32 PM PST US Subject: Re: AeroElectric-List: Re: Jabiru Alternator From: Rob Turk Jabiru uses Kubota regulators, type Kubota RP201-53710 On the Jabiru engines, a common issue is the connection from the coil to the regulator and from the regulator to the battery and ground. The spaces in the Kubota regulator are underrated for the application. Advice is usually to cut off the original and use good quality spade connectors. Rob On 9/12/25 21:04, dj_theis wrote: > > I second Joes suggestion. > > Ive tested the JD rectifier/regulator and found them to be good substitutes for whatever OEM R/R are supplied (single phase PMs only, of course). > > The only caution might be that these R/R devices have been on the market for a while and there might be less than ideal copies available. > > Purchasing from John Deere (or a reliable substitute provider), as Joe implies with the JD part number, is generally a reliable source. > > -------- > Dan Theis > Scratch building Sonex #1362 > Revmaster Alternator problem solved. > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=515622#515622 > > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.