Today's Message Index:
----------------------
1. 12:27 AM - Re: Is there a need for a heatsink for the B&C e-buss dio... (Fiveonepw@aol.com)
2. 06:07 AM - Cheap 12v fans (Terry Miles)
3. 07:50 AM - Re: Two Circuits on One Fuse? ()
4. 08:16 AM - Re: Re: Can Rotax be self exciting? ()
5. 10:20 AM - Re: Two Circuits on One Fuse? (Jekyll)
6. 03:37 PM - Re: Re: Two Circuits on One Fuse? (Doug Windhorn)
7. 08:22 PM - Re: Is there a need for a heatsink for the B&C e-buss diode? (Robert L. Nuckolls, III)
8. 08:25 PM - Re: Cheap 12v fans (Robert L. Nuckolls, III)
9. 09:21 PM - Re: Re: Odessey Battery Capacity Test (Robert L. Nuckolls, III)
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: Is there a need for a heatsink for the B&C e-buss |
dio...
In a message dated 5/24/2007 4:11:52 PM Central Daylight Time,
retasker@optonline.net writes:
The best way to solve this problem would be to buy a 12V cooling fan.
They are readily available - even at Radio Shack (although theirs are
somewhat costly).
>>>
Yep- or try _www.mpja.com_ (http://www.mpja.com) and hunt for "fans"- I'm
having trouble getting their website open right now for a direct link, but look
for items like stock # 16496-FN, for $3, or #16543-FN for $4. These are both
12VDC and 2-3/8" and 3-5/8" square respectively, according to a catalog I have
that is maybe 6 months old.
They sell lots of other cool stuff, and there are other sources like this if
you have a few hours for googlin'...
Mark
************************************** See what's free at http://www.aol.com.
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 |
|
Try calling around at local auto stereo install shops for discarded parts.
I just happened on one that way. $5. It was in there junk box with a lot
of heat sink AL that he just gave away.
Terry
Velocity
Chasing stray electrons
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Richard
Tasker
Sent: Thursday, May 24, 2007 5:04 PM
Subject: Re: AeroElectric-List: Is there a need for a heatsink for the B&C
e-buss diode?
<retasker@optonline.net>
The best way to solve this problem would be to buy a 12V cooling fan.
They are readily available - even at Radio Shack (although theirs are
somewhat costly).
Dick Tasker
William Crook wrote:
> Hi Group:
>
> Quick question: Is there a need for a heatsink for the B&C e-buss
> diode? I am mounting the diode on .065 aluminum sheet under the glare
> shield. Would that suffice? If I need a heat sink, what size?
>
> Also, what is the most economical/elegant way to step down 12.8
> volt ship's power to 5 volts for an "avionics" cooling fan (i.e., a
> computer cooling fan from Radio Shack)? Thanks,
>
> Will Crook
> Glastar
> Waynesville, NC
>
>*
>
>
>*
>
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: Two Circuits on One Fuse? |
Dear Bobair8:
Yes you can do it and your house does it all over the place. In
fact you could gang more than two if careful.
Before Bob's concept of using modern automotive fuses, most
planes ganged circuits on one protection device, be it fuse or
circuit breaker all the time. How many small Cessna's have 30
fuses or CB's. Its a nice luxury to have an individual "fuse" for
every circuit and has obvious advantages, like when one blows
you lose one item.
However from a safety stand point you can "gang" circuits on
a fuse and it will be as safe and more practical with some
precautions. (Practical means less fuses than the space
shuttle.)
SIMPLICITY (examples)
You could put in ONLY 10 amp fuses in for all circuits and run
as many 18 awg wires and circuits you like, 1, 2 or 3 or more, if
the total is under 10 amps. This is what many planes do. So
you are just putting in bigger but fewer fuses or CB's.
***********************************************
However it is more than the current draw of the items you must
look at. You have to look at wire protection, which is the real
reason for the fuse or CB.
You want (must) make sure the fuse does not exceed the
wires capability.
***********************************************
EXAMPLE:
Say you have 3 items on one fuse and they are each 3.3 amp
with a short wire run. So 22 gage wire is enough for each
individual 3.3 amp run.
(Note: For electrical, 20 awg is a nominal min gauge just for
simplicity and durability. If wiring a large aircraft you would
use 22, 24 and even 26 awg to save weight. For data wiring,
like a transponder 22 awg is fine, making those busy plugs
easier to manage. All my humble opinion, pls no hate mail.)
So a +10 amp fuse would be fine for all three, but you might
go with say the next size up, a 15 amp fuse. Lets say one wire
shorted and the other items where off or drawing min current.
A 22 gage wire would get too hot before fuse blowing a 15 amp
fuse for my comfort (190F?). Now a 22 gauge wire will actually
fuse at 41 amps, but lets say its a "soft short" and the wire
is getting hot but the short is not great enough for the fuse
to blow? You will smell it and 190F might ignite something.
Rule of thumb: 22 awg would use 7 amp, 20 awg = 11 amps
and 18 awg = 16 amp fuses for max chassis wiring. If circuit is
for continuous voltage transmission over long distance, the
wire's current ratings are much lower than above "max.
Again this is all about wire protection than second total current.
The solution is very simple go to 18 awg wire to handle the 16A
load, so each wire at fuse rating is safe, not just the individual
load. Clearly 18 awg is over kill for 3.3 amps over a short length
but perfect for 15 amp fuse. Personally I would pick smaller loads
than 3.3 amps to gang and of course pick non "critical" items.
It's better to match similar ratings together of course,
eg, don't match 8 amps with a bunch of 1/2 amp circuits.
There is nothing keeping you from putting 3 or 4 (one) amp items
on a 5 amp fuse with 20 awg wire. However I would knock it off
at a gang of 3 my self, but there is no rule, just common sense.
CAUTION: Be sure you can lose all items in one shot from a
mission critical standpoint. Now simplify!
George ATP/CFI-II-ME/MSME
>From: Kevin Horton <khorton01@rogers.com>
>Subject: Re: AeroElectric-List: Two Circuits on One Fuse?
>
>The fuse needs to be big enough to comfortably handle the worst
>case total load that could be produced by both devices.
>Kevin Horton RV-8 (finishing kit)
---------------------------------
Looking for a deal? Find great prices on flights and hotels with Yahoo! FareChase.
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: | Re: Can Rotax be self exciting? |
Thanks Richard,
This is very interesting. We'll if it works on a Ducati... Any idea
if there is anything like this available for a Subaru? Does it matter?
Could this be adapted to any electrically dependent system?
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Hoffmann D- Remscheid
Sent: Thursday, May 24, 2007 3:39 PM
To: aeroelectric-list@matronics.com
Subject: AeroElectric-List: Re: Can Rotax be self exciting?
Hello,
I have found two aftermarket products which claim to run without
battery with capacitor only:
http://www.schicke-electronic.de/dgr3.htm switches near the zero
transition and thus produces very low noise. Consider the cooling fins
in comparison to the original Rotax regulator and You may believe it is
a product designed for very long life.
http://www.silent-hektik.com/Duc_R_Rot.htm run Rotax injection
which is electrical dependent. They say that the engine will continue
running as long as it is above 1000rpm with capacitor only.
Hope that helps especially for the 912 / 914 engines
Bob is right once more (:-)
Richard
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: Two Circuits on One Fuse? |
I ganged several of my fuses. I agree with what's been said above so I'll just
stay with a systems approach to add something to the topic.
You didn't say if you are using an E-bus or just a main bus. Your architecture
bears on the process. First, I wouldn't gang anything I would consider appropriate
for an E-bus. Those items are by definition the minimum requirements for
safe continued operation. I wouldn't introduce any chance of sympathetic failure
to my essential systems. Those circuits should be carefully planned to maximize
reliability.
Gang only unrelated items, non essential or those with other backups:
- Gang all your internal lights and panel lights. Carry a flashlight for a backup.
I carry several when night flying including a LED on a neck lanyard.
- Gang your flaps with something such as position lights. You can safely fly without
either in a pinch.
- Gang intermittent items such as trim, taxi lights.
Just some ideas to ponder.
In the end, you can add to your fuse block without really adding to your fuse block.
Run a single fused wire to a terminal block and run individual power runs
from there using in-line fuses. Another method is to run a single wire to all
CB's you may still use. In my plane, I have fuses but decided to install pullable
CBs for pitch and roll trim so I could rapidly locate and turn off the trims
in case of a run away condition. I ran 1 fused wire to the daisy-chained
CBs. Each CB protects its down stream wires and the power run is fused and sized
to feed both CBs.
George, good info.
Jekyll
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=114746#114746
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: | Re: Two Circuits on One Fuse? |
May as well throw in a few more veggies into the soup here.
I am not a fan of "ganging," but would consider it in some cases. If one is
short several fused terminals, I would add another fuse block with a short
supply lead from the supply of the first block or direct from the firewall .
Since I would tolerate only 2-3 of these cases, I would then look for the
low current need equipment, 1-2 amps. Here's the reason. Minimum
recommended wire size is 22 ga which would be protected with a 3 amp or less
fuse. Combining a couple 1 amp devices on this 3 amp fuse would not
increase the need to upsize the wire to either device.
If the combined power need of ganged leads approached or exceeded 3 amps, I
would jump to a 5 amp fuse and change the feed wires to each device ganged
to this fuse from 22 ga to 20 ga.
Anything more than that, give me another buss. They're not expensive.
Ganging larger demand devices may be OK if there is no likelihood they will
be active at the same time, but the fuse needs to be sized to protect the
smallest wire and you must be prepared to not miss those devices in case the
are both powered at the same time and blow a fuse in the process.
Regards, Doug Windhorn
----- Original Message -----
From: "Jekyll" <rcitjh@aol.com>
Sent: Friday, 25 May, 2007 10:17
Subject: AeroElectric-List: Re: Two Circuits on One Fuse?
>
> I ganged several of my fuses. I agree with what's been said above so I'll
> just stay with a systems approach to add something to the topic.
>
> You didn't say if you are using an E-bus or just a main bus. Your
> architecture bears on the process. First, I wouldn't gang anything I would
> consider appropriate for an E-bus. Those items are by definition the
> minimum requirements for safe continued operation. I wouldn't introduce
> any chance of sympathetic failure to my essential systems. Those circuits
> should be carefully planned to maximize reliability.
>
> Gang only unrelated items, non essential or those with other backups:
> - Gang all your internal lights and panel lights. Carry a flashlight for a
> backup. I carry several when night flying including a LED on a neck
> lanyard.
> - Gang your flaps with something such as position lights. You can safely
> fly without either in a pinch.
> - Gang intermittent items such as trim, taxi lights.
>
> Just some ideas to ponder.
>
> In the end, you can add to your fuse block without really adding to your
> fuse block. Run a single fused wire to a terminal block and run individual
> power runs from there using in-line fuses. Another method is to run a
> single wire to all CB's you may still use. In my plane, I have fuses but
> decided to install pullable CBs for pitch and roll trim so I could rapidly
> locate and turn off the trims in case of a run away condition. I ran 1
> fused wire to the daisy-chained CBs. Each CB protects its down stream
> wires and the power run is fused and sized to feed both CBs.
>
> George, good info.
>
> Jekyll
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=114746#114746
>
>
>
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: | Re: Is there a need for a heatsink for the B&C e-buss |
diode?
At 10:37 AM 5/24/2007 -0700, you wrote:
>Hi Group:
>
>Quick question: Is there a need for a heatsink for the B&C e-buss
>diode? I am mounting the diode on .065 aluminum sheet under the glare
>shield. Would that suffice? If I need a heat sink, what size?
What's your e-bus loads? For 10A or less, mount to any metal surface.
>
>Also, what is the most economical/elegant way to step down 12.8 volt
>ship's power to 5 volts for an "avionics" cooling fan (i.e., a computer
>cooling fan from Radio Shack)? Thanks,
Go with a 12v fan.
http://mpja.com/listitems.asp?dept=48&main=46
http://tinyurl.com/ypxuaw
http://dkc3.digikey.com/PDF/T072/2002.pdf
http://dkc3.digikey.com/PDF/T072/2004.pdf
Three pages of stuff here:
http://dkc3.digikey.com/PDF/T072/2006-2009.pdf
http://tinyurl.com/2u3db7
Bob . . .
----------------------------------------
( "Physics is like sex: sure, it may )
( give some practical results, but )
( that's not why we do it." )
( )
( Richard P. Feynman )
----------------------------------------
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: | Re: Cheap 12v fans |
At 09:03 AM 5/25/2007 -0400, you wrote:
><terrence_miles@hotmail.com>
>
>Try calling around at local auto stereo install shops for discarded parts.
>I just happened on one that way. $5. It was in there junk box with a lot
>of heat sink AL that he just gave away.
Be wary of used fans of any kind in your project. Fans have
quirky service lives, especially in intermittent duty on
airplanes. Put in a NEW fan and be mindful of any increase
in noise that might indicate a bearing getting dry.
I've seen a number of expensive failures preceded by
the failure of an inexpensive or poorly cared for
fan. Not the least of these experiences was with
a computer in my office.
Bob . . .
Message 9
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: Odessey Battery Capacity Test |
At 10:58 AM 5/24/2007 -0400, you wrote:
><eanderson@carolina.rr.com>
>
>Thanks, Charlie.
>
>I have been flying with one Odyssey PC680 - 14 1/2lbs after getting rid
>of my 2 Concord RGC 25 AH batteries each weighing 22 1/2 lbs - can you say
>44 lbs of battery. One went bad after 6 months and I replaced them with 2
>Odyssey. After flying with 2 Odyssey for 3 years, I finally removed one
>and have been flying with one for 3 years.
>
>A battery than can give that kind of performance after six years is the
>battery for me.
>
>Ed
I hear many anecdotal statements about battery life. Will
probably hear a bunch more at OSH this years (I'll be hanging
out in the Concorde Battery booth for awhile and I'm trying
to get a Saturday evening slot in the tents).
The question seldom asked and even less often answered is,
"Does your x-year old battery support minimum equipment loads
for a period of time consistent with you PLANNED recovery
from an in-flight failure of an alternator?"
Just because it's getting the engine started doesn't mean
it's going to be as useful as you would like when the curtain
raises on the play scripted for your own dark-n-stormy-night
story. If you're need for battery performance is governed
by a day-vfr only use of your airplane, then cranking the engine
may be everything you expect the battery to do for you.
However, if you'd like to run a certain bevy of electro-whizzies
reliably for say 3-4 hours after the alternator quits, then
perhaps your battery has been "failed" for several years.
Time: 08:03:25 AM PST US
From: "Tinne maha" <tinnemaha@hotmail.com>
Subject: AeroElectric-List: Re: Odessey Battery Capacity Test
I don't get it...........I thought the purpose of the capacity test was to
see how long the ship's battery could power the essential bus & stay above
10.5 Volts. If the amount of time this takes is within the pilot's zone of
comfort (i.e. enough to land safely), then the battery is deemed sufficient.
Any battery's ability to start an engine is tested at each startup.
Assuming the above is true, I don't see what this particular test
accomplished. Can someone explain what I'm missing?
Not sure what knowledge was added by cranking the engine too
but obviously, some level of endurance for the stated list
of appliances was demonstrated too.
Bob . . .
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! --
|