Today's Message Index:
----------------------
1. 02:29 AM - Re: Re: AeroElectric-List: Re: Rotax 912 UL alternator drop-out (FLYaDIVE)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: AeroElectric-List: Re: Rotax 912 UL alternator |
drop-out
Good report Paul.
A practical approach has prevailed.
Now since you know 10 Amps will overload the system and 5 to 6 Amps is
borderline for an overload. The next thing to do is COOL the unit and
apply 5 to 6 Amps and see if it stays online. If it stays online you now
know cooling is required.
Barry
On Sun, Aug 18, 2013 at 11:57 AM, Paul Kuntz <paul.r.kuntz@gmail.com> wrote:
> Several inputs suggested checking the connections on the leads coming from
> the alternator, and checking the system ground connections. I checked the
> faston-type alternator lead connections, which were clean and tight. I
> checked all of the ground connections, which were also tight. Yesterday I
> went up for a test flight and confirmed the symptoms under varying system
> loads. The normal system voltage with alternator on line is 13.8 volts,
> which is consistent with what others are reporting for the Rotax Ducati
> regulator. I see a max load of 10 amps with everything running, so I am
> satisfied that the total load is well within the standard Rotax system
> capacity. I also observed that the system voltage drops to 13.5 volts at
> the 10 amp max load, which seems abnormal. Under this max load, the
> alternator dropped out after a few minutes, indicated by system voltage
> dropping to around 12.5 volts -- consistent with fully charged lead-acid
> battery.
>
> When I reduced the load to 3 amps, which is my practical minimum (one
> Dynon display, radio and transponder), the alternator came back and stayed
> there, with system voltage at the normal regulator set point of 13.8
> volts.
>
> I repeated this experiment a few times for various loads, finding that a
> total load above 5 or 6 amps will cause the alternator to drop out after a
> few minutes, and that it will come back when the load is reduced to 3
> amps.
>
> I am pretty well convinced that my voltage regulator is bad. I did learn
> from comments on this issue that Van's includes a voltage regulator cooling
> kit with its lighting kit for the RV-12, consisting of a length of plastic
> tubing that connects from the air intake duct to a shroud over the
> regulator, providing a direct blast of cooling air to counteract the
> increased electrical load of the lighting. So there is certainly
> indication that the Ducati regulator is susceptible to overheating under
> load. The RV-12 regulator is on the engine side of the firewall, however,
> and mine is on the cabin side. At 10 amps with the regulator mounted in
> the cockpit environment, I'm thinking the regulator should be able to
> handle the load without supplemental cooling. Others have noted the
> not-so-good reputation of the Ducati regulator, but there are thousands of
> them in service on Rotax engines worldwide, so rather than tackle a
> reconfiguration of my regulator and wiring installation at this point , I
> ordered a replacement Ducati from Lockwood Aviation and will see how it
> goes. I also ordered a overvoltage protection module from B&C, since the
> Pipistrel electrical system does not include one. I'll install it with the
> new voltage regulator.
>
> I'll report my findings after installing the new regulator.
>
> Paul Kuntz
>
>
> On Sat, Aug 10, 2013 at 10:21 PM, Paul Kuntz <paul.r.kuntz@gmail.com>wrote:
>
>> Thanks for the tips, everyone. I concur with Bob that my Ducati
>> regulator is done for and should be replaced. I will take a look at the
>> Schicke unit that Peter mentioned.
>>
>> Cheers,
>> Paul Kuntz
>>
>>
>> On Friday, August 9, 2013, Robert L. Nuckolls, III wrote:
>>
>>> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <
>>> nuckolls.bob@aeroelectric.com>
>>>
>>> At 12:55 PM 8/9/2013, you wrote:
>>>
>>>> Thanks for the tip. I'll check this cooling shroud idea. I'm also
>>>> wondering if my regulator has already been compromised. Any opinions on
>>>> what my repeated fail/recover situation indicates? I would guess that it
>>>> cycled between failed and recovered 8 or 10 times before we established a
>>>> state where it stayed on line, limited to a total current draw of 3 amps.
>>>>
>>>
>>> If your regulator can't carry 10A without cooling, it's
>>> probably broke. A functional part should be capable of
>>> rated output for the alternator which is on the order
>>> of 18A. I've not heard of any mass-movements to forced
>>> air cool these regulators.
>>>
>>>
>>>
>>>
>>> Bob . . .
>>>
>>> ====**==============================**=
>>> -List" target="_blank">http://www.matronics.com/**
>>> Navigator?AeroElectric-List
>>> ====**==============================**=
>>> http://forums.matronics.com
>>> ====**==============================**=
>>> le, List Admin.
>>> ="_blank">http://www.matronics.com/**contribution
>>> ====**==============================**=
>>>
>>>
>>>
>>>
> *
>
> *
>
>
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|