Today's Message Index:
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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
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| Subject: | Re: Jabiru Alternator |
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
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| Subject: | Re: Jabiru Alternator |
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
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| Subject: | Re: Jabiru Alternator |
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
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| Subject: | Re: Jabiru Alternator |
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
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| Subject: | Re: Jabiru Alternator |
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
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| Subject: | Re: Jabiru Alternator |
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
>
>
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