 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
wdleonard(at)gmail.com
Guest
|
 Posted: Sun Apr 22, 2007 8:35 am Post subject: ELT Misfire.. Main solenoid |
 |
|
Two years ago....
There I was JMMOB (an official medical abbreviation at some hospitals for Just Minding My Own Business), home with my parents watching TV when my cell rings.... Turns out the manhunt had finally located my 'downed' aircraft parked safely on the transient ramp with the ELT humming away... Talk about embarrassing. I drove to the airport and found a team of 14 year-old (dare I say) nerds pointing electo-gadgets at my plane. Their leader insisted that I pull the ELT to get the S.N. I had 'wisely' installed my ELT under the baggage floor, so at 10pm the elctro team had to spend another hour watching me unload all the stuff in the cargo area, remove the seats, remove the floor, just to get the S/N off the ELT (it is now recorded in the owner documentation). Sorry about that.
Anyway, I had assumed that some un-noticed bump had triggered the ELT. A few times over the curse of the next year I had occasionally caught the ELT light flashing while putting the plane away.. This disturbed me as I could never come up with a good reason... I even blamed my passenger once for accidentally pressing the activation button (which is near the pax headset jack).
But last night I finally found the problem. While playing with the electrical system, I was able to get the ELT to activate several times when shutting off the main solenoid. Isn't there some sort of current spike generated on shut off? Could that be triggering my ELT (ACK)? Has anyone had a similar problem? Know of a fix? I have not installed a diode on my solenoid like electric Bob recommends.. Will that fix the problem?
--
David Leonard
Turbo Rotary RV-6 N4VY
N4VY.RotaryRoster.net
www.RotaryRoster.net
[quote][b]
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
|
|
|
| Back to top |
|
 |
wdleonard(at)gmail.com
Guest
|
| Posted: Tue Apr 24, 2007 6:14 am Post subject: ELT Misfire.. Main solenoid |
|
|
I am sure the spike catchers would work too. Not sure why ACK recommended a cap there instead of a diode except...
If you read Bob's stuff carefully, he has an article where he discourages the use of spike catchers anywhere that failure of the diode could connect the battery to ground. Such is the case with the diode on the main contactor. If it fails closed, it will cause an short to ground.
I know these diodes are reliable, but there have been some instances where they failed and started a fire. Apparently that is why certified installations don't use them.
I am no gEEk either (no offense intended). I have no idea about the likelihood of the diodes failing vs. switches wearing out. Not knowing what to do, I left off the spike catchers off because 1) I don't mind burning through master switches all day if it means reducing the likelihood of a fire, 2) if these diodes are so critical why dont all the contactors come with them? (turns out my starter solenoid has one built-in)... and in fact E-Bob more stronly recommends them for starter contactors then master battery contactors.
I'm not sure if a cap is any more reliable than a diode, but my guess is that its failure mode is more likely to be open circuit rather than closed like the diodes. So if it fixes my ELT problem I'll stick with it rather than the diode... unless someone talks me out of it 
I am guessing that another fix of the ELT problem could include a resistor in the 'test' circuit of the ELT remote.
David Leonard
Turbo Rotary RV-6 N4VY
N4VY.RotaryRoster.net
www.RotaryRoster.net
On 4/23/07, Dan Checkoway <dan(at)rvproject.com (dan(at)rvproject.com)> wrote: [quote] Ah. Do you have "spike catching" diodes on your contactor(s)? The attached image shows a couple of diodes on my contactors.
See the middle of this page:
http://www.rvproject.com/20030526.html
...the top of this page:
http://www.rvproject.com/20030528.html
...the middle of this page:
http://www.rvproject.com/20030607.html
...and/or this photo/diagram:
http://www.aeroelectric.com/Pictures/Contactors/s701-1.jpg
Not sure if any of that is helpful, but if you don't have spike catching diodes on your contactors that could be the solution. I suspect a capacitor does the same thing just more "softly." I'm no electrical engineer!
Hope this helps!
)_( Dan
[quote] ---
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
