Today's Message Index:
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1. 06:53 AM - Re: Is there any reason to have a separate battery and alt swit (budyerly@msn.com)
2. 10:47 AM - Re: Is there any reason to have a separate battery and alt swit (h&jeuropa)
3. 11:22 AM - Re: Re: Is there any reason to have a separate battery and alt swit (Pete)
4. 02:38 PM - Re: Re: Is there any reason to have a separate battery and alt swit (William Daniell)
5. 02:39 PM - Re: Re: Is there any reason to have a separate battery and alt swit (William Daniell)
6. 02:59 PM - Re: Rotax 914 and Dynon comparability to calculate actual fuel u (budyerly@msn.com)
7. 05:08 PM - Re: Re: Is there any reason to have a separate battery and alt swit (Gilles Thesee)
Message 1
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Subject: | Re: Is there any reason to have a separate battery and alt |
swit
Sorry for the long delay. My virus protection doesn't like the matronics site.
As for the ROTAX alternator. It is a dynamo so it does not require electrical
excitation of the field circuit as there is none. Even the ignition coils in
the stator are self generating. Pretty simple, basically a big lawn mower electrical
system. So either battery, dynamo (ROTAX alternator), or both is not
going to hurt a thing.
Your automotive or standard alternator (even certified aircraft) require voltage
to excite a field current before the rotating coils can provide power. Alternators
are lighter, more powerful and cheaper to make watt to watt.
An alternator is dependent on the battery to initiate the field. Cut the field
and battery in a Cessna, then turn on only the battery, and the alternator will
not fire, unless there is residual voltage stored in a capacitor in the system
with enough energy to excite the field coil. To my limited knowledge of all
solid state equipment currently available, that power backup to the main bus
to excite an alternator field is no longer available. All backup batteries
simply power the box only.
Best Regards,
Bud Yerly
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=496378#496378
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Subject: | Re: Is there any reason to have a separate battery and alt |
swit
Will,
As Gilles pointed out above, the weak point of the Rotax system is the Ducatti
rectifier/regulator. The electrical design is fine, the problem is the construction.
Early ones, P/N 343620, had diodes that unsoldered internally. There
is an easy work around for this (2 external diodes). Later ones, P/N 362001,
are poorly manufactured with cold solder joints, unsoldered joints and mechanical
failures. Either one seems to work pretty well if the load is kept low, certainly
less than 10 amps and best if closer to 5 amps.
Silent Hektik regulators, made in Germany have been used by many Rotax owners.
They are difficult to purchase in the US, although they may be available from
Vans Aircraft as an alternate on the RV12.
Some owners have purchased John Deere garden tractor regulators and used them with
success. Part number AM101406 is usually the one mentioned.
B&C Speciality has just developed a replacement for Ducatti, the part number is
AVC1. You can find an install manual on their website but it's not yet listed
for sale.
I built a Mike Miller replacement. Mike is an electrical engineer with a RV12.
Ducatti failures are pretty common in them. He inspected many failed Ducatti
units and summarized the problems as stated above. He designed a replacement
that is electrically identical but has more robust components and most importantly
larger heat sink. His will operate at 20 amps all day!
Our Europa draws about 8 amps in flight. We used an early Ducatti with external
diodes for many years. At some point we purchased the later model Ducatti and
used that for a couple years. Finally a year ago I built the MM replacement
and have had no problems.
I hope this offers some insight and maybe solutions. Your 70A spike sounds like
an instrumentation problem, but other than temporarily installing a second ammeter,
I don't have a solution in mind.
Jim Butcher
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=496382#496382
Message 3
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Subject: | Re: Is there any reason to have a separate battery and |
alt swit
Hi Jim!
Could you share the Miller design? I assume it can be easily tweaked go give earthX
battery charge levels(?)
Cheers snd thx!
Pete :)
C-GNPZ
> On May 15, 2020, at 1:58 PM, h&jeuropa <butcher43@att.net> wrote:
>
>
> Will,
>
> As Gilles pointed out above, the weak point of the Rotax system is the Ducatti
rectifier/regulator. The electrical design is fine, the problem is the construction.
Early ones, P/N 343620, had diodes that unsoldered internally. There
is an easy work around for this (2 external diodes). Later ones, P/N 362001,
are poorly manufactured with cold solder joints, unsoldered joints and mechanical
failures. Either one seems to work pretty well if the load is kept low,
certainly less than 10 amps and best if closer to 5 amps.
>
> Silent Hektik regulators, made in Germany have been used by many Rotax owners.
They are difficult to purchase in the US, although they may be available from
Vans Aircraft as an alternate on the RV12.
>
> Some owners have purchased John Deere garden tractor regulators and used them
with success. Part number AM101406 is usually the one mentioned.
>
> B&C Speciality has just developed a replacement for Ducatti, the part number
is AVC1. You can find an install manual on their website but it's not yet listed
for sale.
>
> I built a Mike Miller replacement. Mike is an electrical engineer with a RV12.
Ducatti failures are pretty common in them. He inspected many failed Ducatti
units and summarized the problems as stated above. He designed a replacement
that is electrically identical but has more robust components and most importantly
larger heat sink. His will operate at 20 amps all day!
>
> Our Europa draws about 8 amps in flight. We used an early Ducatti with external
diodes for many years. At some point we purchased the later model Ducatti
and used that for a couple years. Finally a year ago I built the MM replacement
and have had no problems.
>
> I hope this offers some insight and maybe solutions. Your 70A spike sounds like
an instrumentation problem, but other than temporarily installing a second
ammeter, I don't have a solution in mind.
>
> Jim Butcher
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=496382#496382
>
>
>
>
>
>
>
>
>
Message 4
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Subject: | Re: Is there any reason to have a separate battery and |
alt swit
Jim
thanks
YES - I have to say I was quite alarmed by 70A! Since I was in the air
some way from a suitable place to land I carried on figuring that all I had
heard indicated that the rotax would be hard put to produce a consistent
18A let alone 70A. The sparks and smoke stayed in the wire.
Of course I checked and rechecked everything but could never replicate the
fault on the ground. This suggests that this is something to do with a
warm engine and high power. As a reuslt of this discussion it occurred to
me that the fault might be the voltage regulator showing signs of failing?
Mine is mounted on the engine side of the firewall so heat could be a
factor.
I have a hall effect sensor on the battery wire and this has never
shown major fluctuations.
So yes Im guessing that its a fault in the dynon or my installation or a
loose connection or a bit of all three.
My next item is to check the output of the alt using an
independent instrument.
Will
William Daniell
LONGPORT
+1 786 878 0246
On Fri, May 15, 2020 at 1:52 PM h&jeuropa <butcher43@att.net> wrote:
>
> Will,
>
> As Gilles pointed out above, the weak point of the Rotax system is the
> Ducatti rectifier/regulator. The electrical design is fine, the problem is
> the construction. Early ones, P/N 343620, had diodes that unsoldered
> internally. There is an easy work around for this (2 external diodes).
> Later ones, P/N 362001, are poorly manufactured with cold solder joints,
> unsoldered joints and mechanical failures. Either one seems to work pretty
> well if the load is kept low, certainly less than 10 amps and best if
> closer to 5 amps.
>
> Silent Hektik regulators, made in Germany have been used by many Rotax
> owners. They are difficult to purchase in the US, although they may be
> available from Vans Aircraft as an alternate on the RV12.
>
> Some owners have purchased John Deere garden tractor regulators and used
> them with success. Part number AM101406 is usually the one mentioned.
>
> B&C Speciality has just developed a replacement for Ducatti, the part
> number is AVC1. You can find an install manual on their website but it's
> not yet listed for sale.
>
> I built a Mike Miller replacement. Mike is an electrical engineer with a
> RV12. Ducatti failures are pretty common in them. He inspected many
> failed Ducatti units and summarized the problems as stated above. He
> designed a replacement that is electrically identical but has more robust
> components and most importantly larger heat sink. His will operate at 20
> amps all day!
>
> Our Europa draws about 8 amps in flight. We used an early Ducatti with
> external diodes for many years. At some point we purchased the later model
> Ducatti and used that for a couple years. Finally a year ago I built the
> MM replacement and have had no problems.
>
> I hope this offers some insight and maybe solutions. Your 70A spike
> sounds like an instrumentation problem, but other than temporarily
> installing a second ammeter, I don't have a solution in mind.
>
> Jim Butcher
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=496382#496382
>
>
Message 5
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Subject: | Re: Is there any reason to have a separate battery and |
alt swit
Bud - So just to check that I understood, I could have the ALT ON and the
BAT OFF without harming the electrical system?
Will
William Daniell
LONGPORT
+1 786 878 0246
On Fri, May 15, 2020 at 9:56 AM budyerly@msn.com <budyerly@msn.com> wrote:
>
> Sorry for the long delay. My virus protection doesn't like the matronics
> site.
>
> As for the ROTAX alternator. It is a dynamo so it does not require
> electrical excitation of the field circuit as there is none. Even the
> ignition coils in the stator are self generating. Pretty simple, basically
> a big lawn mower electrical system. So either battery, dynamo (ROTAX
> alternator), or both is not going to hurt a thing.
>
> Your automotive or standard alternator (even certified aircraft) require
> voltage to excite a field current before the rotating coils can provide
> power. Alternators are lighter, more powerful and cheaper to make watt to
> watt.
>
> An alternator is dependent on the battery to initiate the field. Cut the
> field and battery in a Cessna, then turn on only the battery, and the
> alternator will not fire, unless there is residual voltage stored in a
> capacitor in the system with enough energy to excite the field coil. To my
> limited knowledge of all solid state equipment currently available, that
> power backup to the main bus to excite an alternator field is no longer
> available. All backup batteries simply power the box only.
>
> Best Regards,
> Bud Yerly
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=496378#496378
>
>
Message 6
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Subject: | Re: Rotax 914 and Dynon comparability to calculate actual |
fuel u
Tony,
Since no one answered:
The Dynon normally uses the Red Cube FT60. Follow the instructions on orientation
and it gives few problems. They are easy to clog if you allow bits of hose
float around in your fuel lines so flush first before install.
I prefer to run my return along side my fuel supply line on the top of the cockpit
module. Then past the bulkhead (mud flap in the rear of the wheel well) then
to a return red cube that is fastened so as to be as straight as possible,
from the top to the return fitting on the tank.
On some aircraft, we put the red cubes together under the baggage bay. The supply
line is near the pump and the return is plumbed into the fuel drain line.
This puts both cubes together for maintenance and allows a single plug for wiring.
Try to keep the cube inlet and outlet as straight as possible and between
the pump and engine on the supply.
See attached Drawing. If it doesn't show, email me direct.
Best Regards,
Bud Yerly
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=496395#496395
Attachments:
http://forums.matronics.com//files/fuel_system_914_mono_europa_209.png
Message 7
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Subject: | Re: Is there any reason to have a separate battery and |
alt swit
Le 15/05/2020 23:33, William Daniell a crit:
Will,
There is a law in physics measurements : the more parameters you
measure, the more you scratch your head^^!
That said, you wrote that your bus - or battery - voltage remained
within the "green" limits during each of the events. So no reason to
suspect the voltage regulator.
The only item capable of supplying more than the 21 amps of the
alternator is the battery, but while doing this its voltage would sag
due to internal resistance (Cf Ohm's law for a generator). 70 amp is no
trifle.
So the main probabilty is an ammeter artefact. The best way to measure
currents is with a Hall effect sensor, as the shunt may induce side
effects in your circuits with high currents.
But first things first, without independent and reliable voltage and
possibly current measurements or logging, no assumptions can be made.
Concerning disconnecting the battery while running, not sure it would be
a safe thing to do, especially in flight :
--
Best regards,
Gilles
http://contrails.free.fr
http://lapierre.skunkworks.free.fr
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