Today's Message Index:
----------------------
1. 09:17 AM - Battery Help ()
2. 10:40 AM - Battery Help Solutions ()
3. 11:13 AM - Re: Warning light press-to-test circuitry (Richard Tasker)
4. 11:21 AM - Re: Battery Help (Matt Prather)
5. 11:45 AM - Re: Warning light press-to-test circuitry (flmike)
6. 12:06 PM - source for S700 series switches (sportav8r@aol.com)
7. 03:56 PM - Re: Warning light press-to-test circuitry (Robert McCallum)
8. 07:47 PM - Re: Warning light press-to-test circuitry (Fiveonepw@aol.com)
9. 08:38 PM - Re: Internally regulated alternator OVP protection ()
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 |
|
--> AeroElectric-List message posted by: <bakerocb@cox.net>
AeroElectric-List message previously posted by: BobsV35B@aol.com
<<Good Afternoon OC, I carry an ancient ICOM IC-A3 transceiver in my
emergency equipment pack.
It is powered by the optional battery pack that utilizes ten standard
double A batteries. I also carry a handheld GPS that is powered by double
A batteries. By carrying enough spare batteries to re-power both units I
figure I have about as much back up communication and navigational
capability as can be
had. Happy Skies, Old Bob>>
AeroElectric-List message previously posted by: "Robert L. Nuckolls, III"
<b.nuckolls@cox.net>
<<I try to avoid adding to the list of cockpit accessories
where ever possible. I fly with dual GPS310 receivers that
use AA batteries and my flight bag back-up is a JHP-520 that
gets new cells every year whether I turn it on or not. I put
new cells into both gps receivers outbound on a long trip
and new ones for the return. The DESIGN GOAL is to avoid
messing with batteries and battery boxes while in-flight . . .
ESPECIALLY in rough air or at night where risk of loosing
something on floor goes up.....skip....>>
4/29/2005
Hello Old Bob and Bob Nuckolls, Thanks for your inputs -- I agree with your
philosophy of using conforming AA battery packs either for primary power or
to back up ni cads. That is how I back up the ni cad battery in my ICOM A-4
hand held when I am flying my KIS TR-1.
Unfortunately there is no conforming AA battery pack available, that I could
find, that would fit my friends rather ancient Garmin GPS Comm so some sort
of jury rig arrangement appears to be the best situation. Buying a new ni
cad battery for the unit I think is still possible, but very expensive and
again in a few years would be of doubtful reliability.
I'll address in a separate posting to the list some of the other solutions
offered.
OC
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: | Battery Help Solutions |
--> AeroElectric-List message posted by: <bakerocb@cox.net>
AeroElectric-List message previously posted by: "Mark R Steitle"
<mark.steitle@austin.utexas.edu>
<<OC, I did a search on "12v battery pack" on ebay and came up with many
items. This particular one comes with a carrying case, wall charger and
a cigarette lighter charger. See
<http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=1502&item=5769065
615&rd=1#ebayphotohosting>
Mark S.>>
4/29/2005
Hello Mark, Thanks for your input. I have not yet learned to speak ebay.
Some comments on that item: It looks like it would do the job. Could not get
a feel for the size and weight. It claims the buyer can replace the battery,
but provides no info on what the battery is. May be a bit pricey -- one
could buy just a small 12v battery, some cigarette lighter socket adapters
from Radio Shack and rig something both smaller, lighter, and cheaper.
There does appear to be a profusion of 12 volt battery packs available, but
it is hard to determine if they would be suitable in the cockpit.
OC
Next item suggested thanks to Dj Merrill, Terry Watson, and Harley Dixon was
the Coleman Powermate Car Battery Booster model number PMB8110. Looks like
it also would do the job. May be an overkill in the weight and size
department. Could not get that data from the web. I am still leary of
depending upon ni cad batteries when reliability of performance is the goal.
OC
Final solution? Right now I am leaning towards a Panasonic (or comparable)
12 volt VRLA battery LC-R121R3P which is relatively inexpensive, small,
light (1.3 LBS), and rechargable. It could be hooked up for both recharging
and use with some PN 270-1590 and PN 270-1527 lighter plug and socket
adapters from Radio Shack, some Fast on terminals,and a few minutes work
with stripper and crimper.
OC
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: Warning light press-to-test circuitry |
--> AeroElectric-List message posted by: Richard Tasker <retasker@optonline.net>
They are probably not necessary, but they do isolate the individual lamp
actuators from the lamp test switch.
It is possible (but probably not likely) that one of the devices that
normally actuate the lamps could be damaged if it were grounded with the
test switch while it wanted the lamp to be off.
Dick Tasker
tonybabb wrote:
>--> AeroElectric-List message posted by: "tonybabb" <tonybabb@alejandra.net>
>
>I'm electrically challenged so sorry if this is a dumb question but ....why
>two diodes? I can see why you'd want a diode between the Push-to-test switch
>and the lamp (because all the lamps would be connected together and you
>don't want one turning on the others) but why another diode between the lamp
>and whatever normally grounds it.
>
>Thanks,
>
>Tony Velocity SEFG
>62% done, 78% to go.
>----- Original Message -----
>From: "Richard E. Tasker" <retasker@optonline.net>
>To: <aeroelectric-list@matronics.com.Gecko/20040803>
>Subject: Re: AeroElectric-List: Warning light press-to-test circuitry
>
>
>
>
>>--> AeroElectric-List message posted by: "Richard E. Tasker"
>>
>>
><retasker@optonline.net>
>
>
>>Use diodes. A set of two diodes for each lamp, anodes connected to the
>>ground end of the lamps (leave the 12V connected as is to the lamps).
>>Cathodes (typically indicated by a line on the cathode end of the diode)
>>of one of the diodes from each set connected to the switch and the other
>>side of the switch connected to ground. Cathode end of the other diode
>>of each set connected to the line that normally turns on the lamp.
>>
>>Press the button and all lamps come on but the ground on the lamp is
>>isolated by the other diodes from the normal lamp actuator. Release the
>>button and all lamps work normally .
>>
>>Dick Tasker
>>
>>Neil K Clayton wrote:
>>
>>
>>
>>>--> AeroElectric-List message posted by: Neil K Clayton
>>>
>>>
><harvey4@earthlink.net>
>
>
>>>I'm struggling with a wiring issue involving panel warning lights;
>>>
>>>Each warning light is part of a circuit between it's associated sensor
>>>
>>>
>and
>
>
>>>ground. The warning lamps always have 12v applied to them. When the
>>>
>>>
>sensor
>
>
>>>triggers, it connects the lamp to ground and the bulb illuminates. Easy!
>>>
>>>I want to be able to touch a press-to-test button to test if the warning
>>>lamps (or diodes in my case) are in fact working.
>>>
>>>This involves a 2nd circuit between the press-to-test button and the
>>>
>>>
>lamp.
>
>
>>>The button clamps the lamp to ground and the lamp lights. Right?
>>>
>>>But...are here are my questions;
>>>
>>>1) To only use one press-to-test button, I need all the lamps connected
>>>
>>>
>to
>
>
>>>it, and by inference, to each other. But this same connection will
>>>illuminate ALL the lamps when one is triggered for real by it's sensor.
>>>
>>>
>How
>
>
>>>do I isolate the lamp for it's "everyday" purpose, but connect it to the
>>>others for testing?
>>>
>>>2) Connecting a lamp to ground for test purposes might have all sorts of
>>>secondary effects on the sensors down the line. How do I disconnect the
>>>sensor while grounding the lamp for test, then re-connect everything
>>>
>>>
>again
>
>
>>>for everyday running?
>>>
>>>Am I complicating this? I suspect I am but I can't see the wood for the
>>>
>>>
>trees!
>
>
>>>Thanks
>>>Neil
>>>
>>>
>>>
>>>
>>>
>>>
>>--
>>----
>>Please Note:
>>No trees were destroyed in the sending of this message. We do concede,
>>
>>
>however,
>
>
>>that a significant number of electrons may have been temporarily
>>
>>
>inconvenienced.
>
>
>>----
>>
>>
>>
>>
>
>
>
>
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: Battery Help |
--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
Is there any chance you could disect the battery pack you have and repopulate
it with new batteries?
Matt-
>
> Hello Old Bob and Bob Nuckolls, Thanks for your inputs -- I agree with
> your philosophy of using conforming AA battery packs either for primary
> power or to back up ni cads. That is how I back up the ni cad battery
> in my ICOM A-4 hand held when I am flying my KIS TR-1.
>
> Unfortunately there is no conforming AA battery pack available, that I
> could find, that would fit my friends rather ancient Garmin GPS Comm so
> some sort of jury rig arrangement appears to be the best situation.
> Buying a new ni cad battery for the unit I think is still possible, but
> very expensive and again in a few years would be of doubtful
> reliability.
>
> I'll address in a separate posting to the list some of the other
> solutions offered.
>
> OC
>
>
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: Warning light press-to-test circuitry |
--> AeroElectric-List message posted by: flmike <flmike2001@yahoo.com>
Neil,
See if this ASCII schematic comes through.
Mike
+12V----lamp--------sensor switch -------gnd
|
+---------|>|----------------------
(1N4001 rectifier) |
|
+12V----lamp--------sensor switch -------gnd |
| |
+---------|>|----------------------
|
|
+12V----lamp--------sensor switch -------gnd |
| |
+---------|>|----------------------
|
|
+12V----lamp--------sensor switch -------gnd |
| |
+---------|>|----------------------
|
|
Normally
open
PTT
switch
|
gnd
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: | source for S700 series switches |
--> AeroElectric-List message posted by: sportav8r@aol.com
Besides B & C, where can I shop for S700 series / Carling / C&H switches? I'm
compiling a vendor list before embarking on a total re-do of my panel (now that
I've read the 'Connection)
-Stormy
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: Warning light press-to-test circuitry |
--> AeroElectric-List message posted by: Robert McCallum <robert.mccallum2@sympatico.ca>
Part of the concern posed in the original question was to prevent the
push to test switch feeding back into the "normal" sensors for the
light. The second diode accomplishes this part of the requested task.
Bob McC
tonybabb wrote:
>--> AeroElectric-List message posted by: "tonybabb" <tonybabb@alejandra.net>
>
>I'm electrically challenged so sorry if this is a dumb question but ....why
>two diodes? I can see why you'd want a diode between the Push-to-test switch
>and the lamp (because all the lamps would be connected together and you
>don't want one turning on the others) but why another diode between the lamp
>and whatever normally grounds it.
>
>Thanks,
>
>Tony Velocity SEFG
>
>
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: Warning light press-to-test circuitry |
--> AeroElectric-List message posted by: Fiveonepw@aol.com
In a message dated 04/29/2005 12:15:01 PM Central Standard Time,
retasker@optonline.net writes:
do I isolate the lamp for it's "everyday" purpose, but connect it to the
>>>others for testing?
>>>>
Went through the same concern while planning my LED annunciator panel. Asked
the same question on the A-list and Bob N. reminded me that during normal
power up and engine start, most annunciators "should" activate in one fasion or
another, telling you the lights are working plus provide real-world operational
checks as well. (which is why they're there anyway!) Master on = oil p,
alt, flaps, canopy and EIS warning all active, flaps up turns that one of, ditto
for canopy latched. Engine start knocks out the rest for a clean annunciator
for taxi. Put the items of interest on your checklist and launch. If any
particular light does or does not light when appropriate, good time to shut down
and investigate. Has worked very well for me after 175 hours...
But then you could always rig up some (ughh!) multi-pole relays for PTT
grounds...
Mark Phillips -6A
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: Internally regulated alternator OVP protection |
--> AeroElectric-List message posted by: <gmcjetpilot@yahoo.com>
THANKS BOB, Great reply. The whole purpose of this discussion is not to worship
auto technology, but to know what you are praying for if you choose to sit in
that church pew.
One-liners: regarding auto alternators (voltage regulator) in your airplane:
-Power system test demonstrated 4.6 million hours MTBF (electronic)
-Expect a min 1/2 million hours MTBF (mean time between failure)
-Internal alternators incorporate a fuse that prevents alternator from melt down
if an OV condition occurs, protecting the airframe, but it may not act fast
enough to prevent avionics equip damage.
Bob, you asked 2 questions or clarifications:
>I didn't see that the IC knows anything about impending failures?
You are correct; nothing says it will predict a transistor is about to fail, as
I indicated. **However, the VR in the ND does have Over Voltage protection, as
do many I-VRs.**
If I have to make one point, internal VR do have OV protection. The question of
how effective or how they work is still up for debate. What does that mean?
I have to assume when over voltage is sensed (17V) the IC will try to shut the
field (MOSFET) down. So if the OV is the symptom of a FET failure, than yes it
will detect a failure, but agreed this is not very predictive. Also the rotor
short protection (detection) although not a direct indication of the FET shorting
as I might have assumed, I wonder if a FET failure could appear as a field
short (ie increasing field current like a field short).
>Where in the narrative do we find a feature that "senses impending overload"?
Predictive (impending) over load/temp may be overstating it. Besides the obvious
normal functions of any VR limiting voltage, there are references made to current
limiting and thermal-overload protection. I recall ND propaganda referring
to reducing alternator output in the event it becomes over heated, but I cant
find the specific technical reference, other than vague terms. Thermal protection
of what: IC, field driver transistor or alternator output rectifier? Many
ICs do have internal thermal shut down protection. Is that a function of alternator
over load? Could be. I found details that support thermal protection
and shut down of a power MOSFET by an IC for other applications, including stereos,
but nothing specific about this in alternator applications. Since FET failures
are preceded with increasing temp this could be somewhat predictive. Whether
any I-VR has thermal protection or not, I don't know, but it is well with
in the capabilities of off the shelf components
to do
this, just might not be cost effective for auto applications. (Keep your alternator
as cool as you reasonably can).
Quote: A power MOSFET contains thousands of parallel devices that are internal,
and you cannot individually protect them. This situation is similar to the well-known
phenomenon of secondary breakdown and you can take steps to avoid its
destruction. One way to overcome this problem is to directly sense the temperature
of the MOSFET by integrating the MOSFET with the controller, and the temperature
can be sensed directly on the FET die.
http://wind.eecs.berkeley.edu/~nesgaard/PATH%20Report%20on%20Power%20System%20Reliability.pdf
Data quoted for reliability of electronic components for individual components
and as a system. This ref is EXCELLENT, directly dealing with the topic at hand,
"power system reliability" (with an eye on protection of unbelievably advanced
automotive electronics which affects safety) Apparently auto technology in
the future will have active electronics with communication links, steering actuation
and collision avoidance using radar and Liar -Light Detection And Ranging!
Note: FIT (Failure In Time -billions hrs).
http://www.koaproducts.com/english/application/ap7.htm
The ND I have, uses a current limit / fusing device; unfortunately its not a diode
as you speak of. From the Berkeley ref above, it points to the fact this kind
of device has a disadvantage in that they can withstand currents 10 times
their normal rating for prolonged time (a fraction of a second?). To get the recommend
1ms failure the fuse cant have more than 4 times norm capacity. So as
an absolute back up to save your avionics from OV, it is not going to help much;
however, it will assure the alternator will die at some point, sooner than
later without catching on fire. Which is real important to anyone using a ND
alternator.
http://www.irf.com/technical-info/whitepaper/s30p5.pdf
Interesting very technical and over my head, but excelling graphical illustration
representing the internal flow inside a FET in failure modes. The main point
is a FET failure is not just one internal event, but also many secondary events.
Apparently the new L MOSFETs are more resilient, but my 25-year-old Pioneer
Stereo (65watt x 2), with MOSFET transistors is still kicking.
Thanks Bob, for giving your insight. When it comes to little alternators with I-VR,
first I can trust that it will NOT cause danger to the aircraft. However
equipment damage "avionics" is *possible* as you and others have stated. With
that said, understanding of *how possible* will help make an informed choice.
I can accept the risk of using a I-VR without extra OV protection since MTBF
is between 200,000-500,000 hours. If I had $30,000 of avionics I would also consider
using additional OV protection, it is more insurance. However, depending
on your design goals, a stand alone I-VR alternator can provide a very good
level of reliability and simplicity. Also, use of standard auto parts may help
on the road if you need to replace it.
Thanks George
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! --
|