On 22/04/2014 13:03, Christoph Both wrote:
> Dear Europa community:
> I am experiencing a strange electrical phenomenon:
> After engine start (Rotax 912ULS) and showing up usually
> at first higher RPM (run up or later, during cruise), my
> MGL V6 radio freezes. I first thought it is a radio
> problem but on the ground, engine OFF it works great, and
> for extended period of time. Frozen means frequencies
> dialed will show on LCD screen but pushing any buttons
> will not work and radio is incapacitated. It remains in
> this state until engine is OFF. I am operating a handheld,
> same frequency which does NOT show any distorted reception
> or TX problems while VX is frozen. The V6 does not RX and
> TX when frozen.
> I have a good set of headphones and hear no unfamiliar
> background noise either. However, I discovered that on my
> GRT Glass, engine monitor graphic analyzer, formerly
> drawing smooth curves for all 4 EGT and CHT sensor
> temps,all 4 parallel temp curves have now sharp steep
> triangular positive and negative spikes, approximately
> every second or so, in irregular patterns +/- and
> different amplitudes. At higher RPM the amplitudes
> increase, at idle they are hardly visible. But, no
> clicking or noise in the headphones.
> I have a straight forward EXP-2 Bus system which worked
> flawless from day #1 until 65 hours FT.
> What really got me confused, and the radio suspect
> questioned is that my electric VSI is now freezing as well
> or freezing at alarming altitude data display (23,000feet
> last time). Where is my oxygen mask?
> I have talked to ROTAX Canada but they had no clue yet.
> Just in case, I ordered a new rectifier unit and capacitor
> in the hope of remedying the problem this way. Parts have
> not arrived yet.
> Any ideas what the issue can be or how to trouble shoot this?
> Thanks,
> Christoph Both
> EUROPA C-GPEL
> 75+ hours, Waterville, Nova Scotia, Canada
I thought I would add my two pennyworth to this.
My Ducati failed at 175 hours.
I have an ammeter and a voltmeter. The ammeter isn't
damped and the voltmeter is.
I tried a total of four new Ducatis and every single one
vibrated the ammeter needle at 5 cycles per second,
between 2 and 10 amps in the cruise. Two of the four came
---From the UK - two from Lockwood.
I assume that the damped voltmeter wasn't able to show the
vibrating voltage at 5 cps, but that it was giving maybe
14 - 16 volts 5 times a second.
My original Ducati did not vibrate my ammeter needle - nor
did two other people's Ducatis. The difference was that
these Ducatis were earlier models.
I beleve that they changed the circuitry, so that the
problem appeared around 2006 - although I would have to
look up the date.
A digital ammeter would not have shown this vibration; I
suspect that others have no ammeter.
Anyway I bought a GR6 and it has happily run for 500 hours
since then, with no ammeter needle vibration.
The GR6 does need a few more revs to get going - 2500 -
and I believe its stated max is 16A rather than the
Ducati's 19A. However as the GR6 has far superior cooliing
fins I am sure the GR6 wil be much more long-lived (I
cover that by having a spare on board - guarantees
non-failure !)
Of course Schicke won't send GR6s to the USA, but there
are ways round that !
By the way the AC output from the stator can get up to 30
volts !
Richard Holder
Europa G-OWWW
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