Today's Message Index:
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1. 07:01 AM - Re: Re: Starter contactors (Jan de Jong)
2. 09:28 AM - Re: Re: Starter contactors (Robert L. Nuckolls, III)
3. 10:11 AM - Re: Purpose of Diodes on Relays (Robert L. Nuckolls, III)
4. 02:13 PM - Re: Starter contactors (user9253)
5. 05:44 PM - Wig-Wag Trouble Shooting (Mike Creek)
6. 06:15 PM - Re: Starter contactors (user9253)
7. 06:52 PM - Re: Wig-Wag Trouble Shooting (Daniel Hooper)
8. 07:32 PM - 2011 List of Contributors (Matt Dralle)
9. 07:55 PM - Re: Wig-Wag Trouble Shooting (Mike Creek)
Message 1
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| Subject: | Re: Starter contactors |
Just a point of information.
According to Rotax 914 installation manual:
starter relay, 75 A, 300 A for 1 s, weighs 145 g (that is 5 ounces) and
requires a fuse of 2 A.
Having 2, if required, would not be so bad.
Jan de Jong
Message 2
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| Subject: | Re: Starter contactors |
I assume that you meant to type S702-1 starter contactor.
Yes
I am reluctant to use a manual battery disconnect switch. It would
add another failure point to the electrical system.
That's one of the risks mitigated by the dual
feed endurance bus.
I assume that you meant to type S702-1 starter contactor.
Yes
I am reluctant to use a manual battery disconnect switch. It
would add another failure point to the electrical system.
That's one of the risks mitigated by the dual
feed endurance bus. Having a manually operated
battery switch adds no new risks beyond those offere
by the legacy battery master contactor.
In the event of a failed closed contactor, it would take me a minute
or more to exit the plane and operate the battery switch. The cost
to buy a second starter contactor is not much more than a quality
manual battery switch.
Where is your battery located with respect to pilot
access to a battery switch. What are your thoughts
about battery disconnect before unplanned arrival
with the earth?
Here's another thought. If all of your electro-whizzies
could be operated through a 7.5A or less fuse, then
you could consider dispensing with the main bus entirely
in favor of a 'super battery bus'. This would require that
every device have it's own ON/OFF switch . . . with
appropriate attention to shut-down-by-checklist to make
sure the battery is available the next time you go
flying. The starter contactor could be located next
to the battery also.
Bob . . .
Bob . . .
Message 3
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| Subject: | Purpose of Diodes on Relays |
At 12:00 PM 12/18/2011, you wrote:
One thing that really surprises me on your lower trace is the fact
there is no variance in the lower trace as the engine cranks. I know
in my plane the lights in the panel dim as the engine is cranked just
because of the current drawn by the starter motor really loads down
the battery. This could be because of the speed of the trace which I
make out to be around 1.500 sec left to right.
This is a bench test wired per the schematic in the
upper right corner and labeled to show where channels
1 and 2 of the 'scope were connected. The picture's
width is 10 x 250 uS or 2.5 mS.
The only place I've actually seen a diode on a switch is on turbine
engines where the starter motor is also the generator (old 206). The
MM specifies the diode be in good working order to protect from
reverse EMF. I was told that from time to time I would see the
diodes again but haven't.
The energy management diode for a contactor should
be installed on the contactor itself . . . or very
near by. For a short time, diodes WERE installed directly
on starter switches. This MIGHT be an artifact of an
AD that folks-who-know-more-about-airplanes-that-we-do
published in response to some start-contact failures
in the legacy off-l-r-both-start keyswitches offered
no by Aircraft Spruce and perhaps others.
The AD erroneously placed the needed diode across the
switch where it had no beneficial effects. This is
discussed here:
http://aeroelectric.com/articles/spikecatcher.pdf
Any diodes across switch contacts should be replaced
by diodes across the coils. This is not so significant
for a turbine powered aircraft . . . the 'starter contactor'
is likely to double as a reverse current cutout relay
for the generator. Eaton-C/H 6041 series contactors
are common . . . their effects on the controlling
switch are not so profound as that of the automotive
two-stage starter solenoids
http://aeroelectric.com/articles/strtctr.pdf
or even the intermittent duty starter contactors
common to the automotive world. Indeed, the contactor
we used to offer as the S702-1 was supplied to us
with the diode already installed.
Bob . . .
Message 4
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| Subject: | Re: Starter contactors |
The battery is located on the engine side of the firewall. It can be reached through
the oil-check door.
I plan to use an automotive 20 or 30 amp relay in place of the master battery
contactor. However, starting current would not go through the relay.
The starter contactor is located close to the battery. My only concern is a
failed closed starter contactor. But that seems to be a remote possibility.
And if it ever happened, it would occur while on the ground.
Thanks for all of the ideas and suggestions.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=361229#361229
Message 5
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| Subject: | Wig-Wag Trouble Shooting |
I've operated a SSF-1 flasher for about 20 hours with the single-switch
configuration. Only the right side lamp comes on in wig-wag and full-on
positions. I've changed the left side bulb to make sure that it is good.
I'm guessing either the flasher or the diode is bad. Any suggestions for
trouble shooting? I suppose I could just order both and change both of
them, but I'm hoping there is a way to tell if either the flasher or diode
is bad.
Thanks,
Mike
Message 6
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| Subject: | Re: Starter contactors |
I had a great idea. Wire two starter contactors in series. They will be energized
by two momentary push button switches, one labeled and in plain sight on
the panel, the other switch hidden. When the barefoot bandit attempts to steal
my plane, he will turn on the master and push the start button. He will hear
one contactor pull in and assume there is an electrical problem because the
engine does not crank. So he will go find another plane that someone left the
key in.
I will not need a key or an expensive key switch because only I will know how
to start the engine (along with everyone else on Aeroelectric). And I will not
have to worry about losing the key or forgetting it. Has anyone ever driven
all of the way to the airport, only to realize the aircraft key was still at
home?
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=361244#361244
Message 7
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| Subject: | Re: Wig-Wag Trouble Shooting |
So you can't get the left side to light under any circumstances? Have you tried
directly energizing it with it disconnected from the wig-wag module? It could
be a wiring issue.
Do you have a multimeter that you can use to check for the presence of voltages
at various points?
--Daniel
On Dec 19, 2011, at 7:40 PM, Mike Creek wrote:
>
> I've operated a SSF-1 flasher for about 20 hours with the single-switch
> configuration. Only the right side lamp comes on in wig-wag and full-on
> positions. I've changed the left side bulb to make sure that it is good.
> I'm guessing either the flasher or the diode is bad. Any suggestions for
> trouble shooting? I suppose I could just order both and change both of
> them, but I'm hoping there is a way to tell if either the flasher or diode
> is bad.
>
> Thanks,
> Mike
>
>
>
>
>
Message 8
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| Subject: | 2011 List of Contributors |
Dear Listers,
The 2011 Matronics Email List and Forum Fund Raiser officially ended a couple of
weeks ago and its time that I publish this year's List of Contributors. Its
the people on this list that directly make the Email Lists and Forums possible.
Their generous contributions keep the servers and Internet connection up and
running!
You can still show your support this year and pick up a great gift at the same
time. The Contribution Web Site is fast, easy, and secure:
http://www.matronics.com/contribution
Or, by dropping a personal check in the mail to:
Matt Dralle / Matronics
581 Jeannie Way
Livermore CA 94550
I also want to thank Bob, Jon, and Andy for their generous support through the
supply of great gifts this year!! These guys have some great products and I encourage
you to visit their respective web sites:
Bob Nucklolls - AeroElectric - http://www.aeroelectric.com
Jon Croke - HomebuiltHELP - http://www.homebuilthelp.com
Andy Gold - The Builder's Bookstore - http://www.buildersbooks.com
And finally, I'm proud to present The 2011 Fund Raiser List of Contributors:
http://www.matronics.com/loc/2011.html
Thanks again to everyone that made a Contribution this year!!
Matt Dralle
Matronics Email List and Forum Administrator
Message 9
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| Subject: | Wig-Wag Trouble Shooting |
Hmm..., yes it could be a wiring issue, however (although my previous post
isn't very clear) it worked fine for about 20 hours, but only the right side
comes on now. I've checked the wiring and connectors visually and by moving
the connectors to ensure they have good contact at the switch, flasher, and
diode. I'm reasonably sure the wiring is fine. Your idea about energizing
the left side is a good one, I'll switch wires for left and right to see if
the left side lights up.
I considered using a volt meter; however, it is in a difficult spot and both
the wig-wag flasher and diode are energized from the same switch (unless one
pole is bad) so I doubt a volt meter would reveal much given the
configuration; but it is certainly worth a try.
Thanks,
Mike
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Daniel
Hooper
Sent: Monday, December 19, 2011 6:49 PM
Subject: Re: AeroElectric-List: Wig-Wag Trouble Shooting
--> <enginerdy@gmail.com>
So you can't get the left side to light under any circumstances? Have you
tried directly energizing it with it disconnected from the wig-wag module?
It could be a wiring issue.
Do you have a multimeter that you can use to check for the presence of
voltages at various points?
--Daniel
On Dec 19, 2011, at 7:40 PM, Mike Creek wrote:
> --> <mwcreek@frontiernet.net>
>
> I've operated a SSF-1 flasher for about 20 hours with the
> single-switch configuration. Only the right side lamp comes on in
> wig-wag and full-on positions. I've changed the left side bulb to make
sure that it is good.
> I'm guessing either the flasher or the diode is bad. Any suggestions
> for trouble shooting? I suppose I could just order both and change
> both of them, but I'm hoping there is a way to tell if either the
> flasher or diode is bad.
>
> Thanks,
> Mike
>
>
>
>
>
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