Today's Message Index:
----------------------
1. 08:32 AM - Ducati regulator question (user9253)
2. 09:42 AM - Vertex VXA700 information needed (rparigoris)
3. 09:54 AM - Re: Panel Accessible breaker for Mission Critical Item (Dennis Johnson)
4. 11:38 AM - Re: Ducati regulator question (John Loram)
5. 11:58 AM - Re: Facet Boost Pump Fuses (messydeer)
6. 05:56 PM - Re: Ducati regulator question (Robert L. Nuckolls, III)
7. 06:05 PM - Re: Facet Boost Pump Fuses (Robert L. Nuckolls, III)
8. 09:21 PM - Electrical Noise Prevention (messydeer)
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: | Ducati regulator question |
I am building an RV-12. Because I am registering as E-LSA, I must build it EXACTLY
according to plans using the pre-assembled wiring harness and control board,
essentially a plug and play system. The schematic may be viewed here:
http://www.vansaircraft.com/pdf/revisions/RV-12/User_Manuals/MM-R1.pdf on page 173 of the 185 page of the Adobe document.
My question concerns the 22awg wire that connects the main bus to the "C" terminal
of the Ducati voltage regulator. First of all, there is no fuse protection
for this 3-foot wire that passes through the firewall. One half of the master
switch is in series with this wire. I thought the "C" terminal was for voltage
sensing. It seems that it is being used as an ON-OFF control for the regulator
on the RV-12. If terminal "C" really is a voltage-sense input, then it
would seem that if the master switch were shut off while the engine was running,
that the regulator would see a low input (0 volts) and put out a higher voltage,
resulting in an over-voltage situation. Another concern is the 22,000f
25vdc capacitor on the control board which is on the cabin side of the firewall.
If the regulator fails and can not be shut off, an over-voltage situation
could smoke the capacitor with no way to shut the power off to it. So here are
my questions:
Does terminal "C" of the Ducati regulator act as an ON-OFF control?
If the regulator fails and allows over-voltage, will opening input to terminal
"C" shut off the regulator output?
Thanks,
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=305065#305065
Message 2
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Vertex VXA700 information needed |
I am trying to hook up a Vertex VXA700 handheld as a second Com to my PS Engineering
PSA4000 audio panel.
Here is link to owners manual (1.01MB):
http://www.vertexstandard.com/indexVS.cfm?cmd=DisplayProducts&ProdCatID 4&encProdID=CDA841ED5B9711A5833A60A9115F5EDE&DivisionID=2&isArchived=1
As per manual on page 65 I have a CT-96 headset cable. The problem is I want the
audio panel to allow the Pilot and Co-Pilot PTT to transmit on Com 2 (Vertex)
when I select Com 2.
Does anyone have a schematic how to wire the CT-96 headset cable to accomplish
this task?
I do have as shown on page 65 the external PTT switch.
This is not a simple device that goes in series with the mic jack and pulls PTT
wire to ground. It has two switches that I believe could be replicated with
a relay that has the coil powered and could look for ground through the PTT pin
of Com 2 on the PMA 4000. I think when the external PTT switch/es are pushed,
it disables the handhelds internal mic while connecting to the mic on headset.
Vertex was not of much assistance. They sent over a Service manual and a diagram
of CT-96, which have errors. When I asked another question that would have solved
my issue, Vertex said they don't make the external PTT and couldn't help
me any further.
Thx.
Ron Parigoris
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=305075#305075
Message 3
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | RE: Panel Accessible breaker for Mission Critical Item |
I've been flying my Lancair Legacy for over three years and 350 hours.
I do not agree with your characterization of a no flap landing in a
Legacy. I wouldn't fly it if I thought it was unsafe to land without
flaps. You're right that you need a higher landing speed and a longer
runway, but at least where I fly, there are a dozen suitable runways
within my normal fuel reserve. The last time I did a no flap landing,
for practice, was on a 6,000' runway at sea level and I don't think I
used more than half the runway. But it is something that needs to be
practiced because you're right that it's much easier with flaps than
without.
There are plenty of single points of failure in the flap system and the
fuse or circuit breaker is only one of them. I'd recommend a
comfortable Plan B if any of them caused a flap system failure.
By the way, I have a 7 amp ATO/ATC fuse protecting my wing flap circuit.
During construction, I installed a 5 amp fuse based on measurements of
the flap motor's current draw. However, once I started flying, I found
that I could sometimes blow the fuse if I instantly reversed the flap
direction. For example, let's say I'm on the ground running the before
takeoff checklist and lowering the flaps to 10 degrees. I overshoot a
little and immediately move the flap lever to the up position to get
back to 10 degrees. That immediate reversal of flap movement sometimes
blew the 5 amp fuse. I replaced it with a 7 amp fuse and have not had a
problem since; about three years and over 300 hours.
Another poster expressed concern about circuit protection for the
landing gear. That's near the bottom of my worries, because the backup
gear extension system relies on gravity and proper installation and
lubrication of the landing gear system. I practice the alternate
landing gear extension from time to time and perhaps that's why I'm so
comfortable with it. My hydraulic pump is protected by a 40 amp ANL
current limiter, which I don't believe the pump could possibly blow,
absent some failure that would disable the system anyway.
Dennis
Message 4
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Ducati regulator question |
begin SPECULATION
While it may have a "sense" function, it is probably the power source for
the internal electronics.
Without the source, the internal electronics won't startup, and the
regulator will remain dormant.
end SPECULATION
This configuration, with a motorcycle regulator, was used on the early
Jabiru engines and in that application powering the regulator without having
the engine running would burn out the regulator and the alternator.
-john-
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On
> Behalf Of user9253
> Sent: Friday, July 16, 2010 8:31 AM
> To: aeroelectric-list@matronics.com
> Subject: AeroElectric-List: Ducati regulator question
>
> --> <fran4sew@banyanol.com>
>
> I am building an RV-12. Because I am registering as E-LSA, I
> must build it EXACTLY according to plans using the
> pre-assembled wiring harness and control board, essentially a
> plug and play system. The schematic may be viewed here:
> http://www.vansaircraft.com/pdf/revisions/RV-12/User_Manuals/M
> M-R1.pdf on page 173 of the 185 page of the Adobe document.
> My question concerns the 22awg wire that connects the main
> bus to the "C" terminal of the Ducati voltage regulator.
> First of all, there is no fuse protection for this 3-foot
> wire that passes through the firewall. One half of the
> master switch is in series with this wire. I thought the "C"
> terminal was for voltage sensing. It seems that it is being
> used as an ON-OFF control for the regulator on the RV-12. If
> terminal "C" really is a voltage-sense input, then it would
> seem that if the master switch were shut off while the engine
> was running, that the regulator would see a low input (0
> volts) and put out a higher voltage, resulting in an
> over-voltage situation. Another concern is the 22,000f
> 25vdc capacitor on the control board which is on the cabin
> side of the firewall. If the regulator fails and can not be
> shut off, an over-voltage situation could smoke the capacitor
> with no way to shut the power off to it. So here are my questions:
> Does terminal "C" of the Ducati regulator act as an ON-OFF control?
> If the regulator fails and allows over-voltage, will opening
> input to terminal "C" shut off the regulator output?
> Thanks,
> Joe
>
> --------
> Joe Gores
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=305065#305065
>
>
>
>
>
>
>
> Photoshare, and much much more:
>
>
>
>
Message 5
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Facet Boost Pump Fuses |
Thanks, Bob :-)
Nice to get some background on how the pump works.
Facet told me in an email 5A would be fine, I see from Table 11-3 of AC43.13-1B
a 5A fuse would work, and you say 7A is peachy. So I'm happy and will think no
more about this issue.
--------
Dan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=305105#305105
Attachments:
http://forums.matronics.com//files/dc_wire_and_circuit_protector_chart_784.jpg
Message 6
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Ducati regulator question |
At 01:35 PM 7/16/2010, you wrote:
>
>begin SPECULATION
>While it may have a "sense" function, it is probably the power source for
>the internal electronics.
>Without the source, the internal electronics won't startup, and the
>regulator will remain dormant.
>end SPECULATION
Seems reasonable. Here's a schematic someone sent me of
what was believed to be at least one version of a Ducati
PM alternator rectifier/regulators. It's typical of
many other diagrams I've seen:
http://aeroelectric.com/Pictures/Regulators/regul_912.jpg
The "C" lead is indeed a voltage sense lead. Further,
it powers the regulation + SCR control circuits.
>This configuration, with a motorcycle regulator, was used on the early
>Jabiru engines and in that application powering the regulator without
having
>the engine running would burn out the regulator and the alternator.
>
While this lead exercises ON/OFF control of the R/R, it's
not in a position to do serious harm if left powered
while the engine is not running. It's worst risk is
that over a long period of time, it might run a battery
down with what amounts to perhaps tens of milliamps
of steady current draw.
> > I am building an RV-12. Because I am registering as E-LSA, I
> > must build it EXACTLY according to plans using the
> > pre-assembled wiring harness and control board, essentially a
> > plug and play system. The schematic may be viewed here:
> >http://tinyurl.com/2d4b9j8
> > on page 173 of the 185 page of the Adobe document.
> > My question concerns the 22awg wire that connects the main
> > bus to the "C" terminal of the Ducati voltage regulator.
> > First of all, there is no fuse protection for this 3-foot
> > wire that passes through the firewall.
Yes . . . this is not in agreement with legacy esign
goals for aircraft . . .
> > One half of the
> > master switch is in series with this wire. I thought the "C"
> > terminal was for voltage sensing. It seems that it is being
> > used as an ON-OFF control for the regulator on the RV-12. If
> > terminal "C" really is a voltage-sense input, then it would
> > seem that if the master switch were shut off while the engine
> > was running, that the regulator would see a low input (0
> > volts) and put out a higher voltage, resulting in an
> > over-voltage situation.
You'd be correct if this were not ALSO a power supply
wire for the R/R . . .
> Another concern is the 22,000=C2=B5f
> > 25vdc capacitor on the control board which is on the cabin
> > side of the firewall. If the regulator fails and can not be
> > shut off, an over-voltage situation could smoke the capacitor
> > with no way to shut the power off to it.
Also correct . . .
> > here are my questions:
> > Does terminal "C" of the Ducati regulator act as an ON-OFF control?
Yes
> > If the regulator fails and allows over-voltage, will opening
> > input to terminal "C" shut off the regulator output?
Very probably. Further, given that the output capability
for the Rotax (and all PM) alternator is relatively low,
the voltage is not going to climb precipitously . . .
If you had an ACTIVE NOTIFICATION of high voltage, this
would probably suffice to offer timely crew notification.
Alternatively, you could add active OV protection like that
illustrated in
http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/Z16M.pdf
I would further suggest, active notification of low voltage
is a good thing too.
Finally, a 3A fuse in series with the "C" lead would be in
conformity with legacy design goals.
Bob . . .
Message 7
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Facet Boost Pump Fuses |
> If it's 20AWG, put a 7A fuse in an don't loose
> any sleep over it. Having too robust a feeder
> protection cannot put anything inside the pump
> at risk.
>
Would this reasoning not lead to running "really" robust feeders/fuses, and
then a fuel pump (or other device) with and internal problem that is
generating a lot of heat (fire/smoke)?
I agree that we're not trying to 'save/protect' the pump, rather trying to
prevent smoking wires, but a smoking load can be a big problem, too.
Most devices we use in our airplanes are considered
not flight worthy if they exhibit any failure mode that
becomes a hazard source for combustion . . . emitting
smoke is frowned upon too. The "really robust" feeders
was more rhetorical than anything else . . . after all,
with a fuse block, one has the option of selecting the
optimal fuse for each application . . . and easily
changing it if later circumstances suggest it's a
good idea. Specifically, with the FACET being a low
energy device totally enclosed in a metal box. The
risks are nil . . .
Emacs!
Although I seem to recall that G. Richter suggested
that the entire airplane could be configured with an
array of one-size-fits-all, self-resetting PTC polyswitches
soldered to a nifty etched circuit board product he
offered. But when it's so easy to achieve the elegant
solution, why not do it?
Bob . . .
Message 8
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Electrical Noise Prevention |
Hi!
I'm finishing up my electrical wiring and am wondering about noise. I'm not sure
what types there are, nor do I know all the sources. I have heard the alternator
and the transmitting radio can cause problems. Also heard that anything with
a pulsing signal could also be a source.
I have a 3 or 4 100-150 Mhz ferrite RF suppressors from MGL http://www.mglavionics.com/EMI_suppressor_for_VHF_frequencies.pdf. It sounds like MGL recommends putting them on any output from the radio, but not the antenna.
I've heard that twisting the feeder line to the noise maker with it's ground coming
back from the device (or having the wires next to each other) will help cancel
out EMF generated noise.
My schematic is posted in another thread: http://www.matronics.com/forums/viewtopic.php?t=72713. The two alternator leads are about 1' long and are wrapped together until one separates to go to the regulator and the other to the alt disconnect relay, which is right next to the regulator. The regulator output wire goes ~6" to a 10k micro (10 mili?) F 50V filter capacitor.
I forgot to label the left and right mag wires, which are dangling out the bottom
center of the pic. The engine instruments will be 6 cht's, 6 egt's, fuel pressure
sender, fuel flow sensor, OT, OP, carb temp, and tach. All these will plug
into the RDAC above the battery. A shielded data cable goes from there back
to the EFIS.
All the wires go through the firewall in either of two firewall penetations, then
join together going to the right side, then back to the instrument panel and
into a wire wrap along a light channel 'tray' along the bottom of the instrument
panel. The pic shows the panel rotated 90 degrees in the open position.
Most of the wires hanging loose are grounds. They'll be bundled together in the
final installation, and if needed, close to the panel feed wires already wrapped.
Besides the mag wires (which are shielded), the only wire with pusling would
be the boost pump. The radio (which may be a handheld) and strobe/nav/pos
lights are not in. I know strobes are notorious noise makers. I have the shielded
cable installed already in the wings.
How does this look to you? Thanks again for taking your time helping me :-)
--------
Dan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=305153#305153
Attachments:
http://forums.matronics.com//files/cabin_wiring_labeled_836.jpg
http://forums.matronics.com//files/firewall_electrical_components_labeled_828.jpg
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! --
|