Today's Message Index:
----------------------
1. 05:07 AM - Re:Starter engaged light, was Starter and contactor wiring (glen matejcek)
2. 08:17 AM - Re: S700-2-50 switch function (user9253)
3. 08:25 AM - Aux Alternator B Lead, Battery Buss (MLWynn@aol.com)
4. 10:32 AM - Re: Re: Starter engaged light, was Starter and contactor wiring (John Burnaby)
5. 11:16 AM - Re: Re:Starter engaged light, was Starter and contactor wiring (Robert L. Nuckolls, III)
6. 11:32 AM - Re: Re: Starter engaged light, was Starter and contactor (BobsV35B@aol.com)
7. 11:39 AM - Re: Re:Starter engaged light, was Starter and contactor (BobsV35B@aol.com)
8. 12:06 PM - Re: Starter engaged light (Robert L. Nuckolls, III)
9. 12:18 PM - Re: Aux Alternator B Lead, Battery Buss (Robert L. Nuckolls, III)
10. 07:24 PM - Re: starter engaged light (Robert L. Nuckolls, III)
Message 1
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| Subject: | RE:Starter engaged light, was Starter and contactor |
wiring
Hi Bob-
> If a starter WERE in a back-drive mode, the polarity
> of voltage would not reverse . . . hence the starter-stuck
> light would not change colors . . . only get much brighter.
>
Duh- I need to stop pondering the digest pre-caffeine.... ;-)
There was an airframe lost a while back due to a stuck contactor and the
ensuing electrical fire, but that involved significantly different and more
robust hardware.
As ever, thanks for your help with the rectal-cranial inversion!
glen matejcek
aerobubba@earthlink.net
Message 2
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| Subject: | Re: S700-2-50 switch function |
Jim,
Perhaps additional components can be used to delay opening of the DP3T switch contacts while switching from one position to another. A large capacitor might help, depending on the current of the load. Or a relay can be used with its contacts in parallel with the DP3T contacts. See the attached sketch. http://tinyurl.com/ya5zkkv
If you post a copy of your schematic, others can offer suggestions.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=285066#285066
Attachments:
http://forums.matronics.com//files/switch_delay_opening_904.jpg
Message 3
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| Subject: | Aux Alternator B Lead, Battery Buss |
Hi all,
I am building an all-electric RV 8 with a rear mounted battery. I was
planning to use Z-12 architecture. On this drawing, both the B lead from the
main alternator and the B lead from the auxiliary alternator terminate (with
appropriate fusing) on the starter contactor hot side and hence to the
aircraft side of the main battery contactor. In reviewing the setup
recommended by Marc Ausman at Vertical Power (still scratching my head on whether
or
not to use the system), he recommends connecting the aux alternator B lead
to the battery side of the battery contactor.
_http://verticalpower.com/docs/VP_Config_2.pdf_ (http://verticalpower.com/docs/VP_Config_2.pdf)
When I asked him why, he said the following:
We wire the secondary alternator to the battery side of the contactor so
that you can still use it if the battery contactor fails. Your normal
operating mode is with the battery contactor closed and using the primary
alternator. If the primary alternator fails, you can switch over to the secondary
alternator. In this failure mode it really doesn't matter which side the
secondary alternator is connected to.
Another scenario is that you are flying along and the battery contactor
fails. The VP-200 automatically detects this failure, load sheds, opens the
battery contactor circuit just to be safe, and then switches over to the
backup alternator. The VP-100 will flag the failure, then you have to manually
switch to the backup alternator. In either case, the secondary alternator
must be on the battery side to operate correctly (the SD-8 is an exception
and will generate power without a battery in the loop, but there are too
many scenarios to get into the nitty gritty).
Power cannot flow from the alternator backwards through the electronic
circuit breakers. So if the battery contactor failed open and both alts are on
the bus side, you'd have no way to charge the battery or use it to
regulate the bus voltage.
Don't forget the secondary alternator b-lead is a hot wire (since it is
connected to the battery) and needs a fuse in back near the battery. This is
indicated on the wiring diagram. Also, the sec alt B-lead is usually a 10
or 12 gauge wire, so it is not that big or difficult to route.
>From a practical wiring point of view, it would be a lot less wire to put
both alternator B-leads to the starter contactor. On the other hand,
running a 10 gauge wire to the battery side of the main contactor would then
provide you with a way to wire a battery buss in the front of the airplane,
as opposed to placing the battery buss next to the battery and running
multiple wires to the front.
I also have dual electronic ignition in this bird, so I am planning to
place a second, small battery in the front that is dedicated to the second
electronic ignition. I don't know if this changes how it should be set up.
On an earlier post, Bob had said something about using a modified Z-14 with
the endurance buss set up as the secondary shown in Z-14.
Anyway, hope this hasn't been to confusing. This forum and the
Aeroelectric book have been an invaluable source of education for a first-time
builder.
Regards,
Michael Wynn
RV 8 Finishing
San Ramon, CA
Message 4
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| Subject: | Re: RE: Starter engaged light, was Starter and contactor |
wiring
I am using a DPST momentary switch, with a lamp in it that is switched
independently, wired to the coil of a starter contactor for my START
button. I plan to wire the internal lamp to one side of the switch so
that it goes on when the START button is depressed and also have a
parallel wire going to the fat wire between the starter solenoid and the
starter. So the lamp will light when I depress the START button and will
go out when it is released...unless the starter solenoid is stuck closed
and the fat wire between the starter solenoid and the starter is
energized.
See any glitches?
Message 5
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| Subject: | Re: RE:Starter engaged light, was Starter and contactor |
wiring
>There was an airframe lost a while back due to a stuck contactor and the
>ensuing electrical fire, but that involved significantly different and more
>robust hardware.
Do you have a source for more information on this
event?
>As ever, thanks for your help with the rectal-cranial inversion!
No problem my friend . . . it's what we do . . .
Bob . . .
Message 6
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| Subject: | Re: RE: Starter engaged light, was Starter and contactor |
Good Afternoon Jon,
Not sure if that is an open question to all or meant for 'Lectric Bob.
Nevertheless, what advantage is it to you to know that the button has been
pressed? Isn't what you really care about whether or not there is power within
the fat wire going to the starter?
Happy Skies,
Old Bob Siegfried
LL22 Stearman N3977A
In a message dated 2/6/2010 12:35:16 P.M. Central Standard Time,
jonlaury@impulse.net writes:
I am using a DPST momentary switch, with a lamp in it that is switched
independently, wired to the coil of a starter contactor for my START button. I
plan to wire the internal lamp to one side of the switch so that it goes
on when the START button is depressed and also have a parallel wire going to
the fat wire between the starter solenoid and the starter. So the lamp
will light when I depress the START button and will go out when it is
released...unless the starter solenoid is stuck closed and the fat wire between
the
starter solenoid and the starter is energized.
See any glitches?
(http://www.matronics.com/Navigator?AeroElectric-List)
(http://www.matronics.com/contribution)
Message 7
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| Subject: | Re: RE:Starter engaged light, was Starter and contactor |
Good Afternoon 'Lectric Bob,
I have a faint memory of a Cessna 210 having that sort of problem. I think
that was the incident that prompted your old company to add starter engaged
warning lights to their new production aircraft..Maybe around 1980 or so?
Am I way off base here?
Happy Skies,
Old Bob
In a message dated 2/6/2010 1:17:41 P.M. Central Standard Time,
nuckolls.bob@aeroelectric.com writes:
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<nuckolls.bob@aeroelectric.com>
>There was an airframe lost a while back due to a stuck contactor and the
>ensuing electrical fire, but that involved significantly different and
more
>robust hardware.
Do you have a source for more information on this
event?
>As ever, thanks for your help with the rectal-cranial inversion!
No problem my friend . . . it's what we do . . .
Bob . . .
Message 8
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| Subject: | Re: Starter engaged light |
At 12:22 PM 2/6/2010, you wrote:
>I am using a DPST momentary switch, with a lamp in it that is
>switched independently, wired to the coil of a starter contactor for
>my START button. I plan to wire the internal lamp to one side of the
>switch so that it goes on when the START button is depressed and
>also have a parallel wire going to the fat wire between the starter
>solenoid and the starter. So the lamp will light when I depress the
>START button and will go out when it is released...unless the
>starter solenoid is stuck closed and the fat wire between the
>starter solenoid and the starter is energized.
>
>See any glitches?
The "starter engaged" light needs to get power from
as far downstream as practical in the power/control
wiring for the starter. The design goal for a starter
engaged light is to annunciate a starter that is still
powered AFTER the start button is released. The
high risk cause for this is a stuck starter contactor.
If you wire your starter engaged light to the start
switch, then the only thing it can tell you is that
the switch is stuck . . . if the contactor is stuck,
it won't stay illuminated.
If you're using an automotive starter contactor with
an "I" terminal . . .
http://www.aeroelectric.com/Pictures/Contactors/s702wire.jpg
. . . then attaching the starter engaged light
to that terminal (protected by a 3A fuse) monitors THAT
contactor. If your contactor is not fitted with an "I"
terminal, then attaching the light wire to the downstream
side of the starter contactor is a good thing to do.
Bob . . .
Message 9
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| Subject: | Re: Aux Alternator B Lead, Battery Buss |
Ausman at Vertical Power (still scratching my head on whether or not
to use the system), he recommends connecting the aux alternator B
lead to the battery side of the battery
contactor. http://verticalpower.com/docs/VP_Config_2.pdf
When I asked him why, he said the following:
We wire the secondary alternator to the battery side of the contactor
so that you can still use it if the battery contactor fails. Your
normal operating mode is with the battery contactor closed and using
the primary alternator. If the primary alternator fails, you can
switch over to the secondary alternator. In this failure mode it
really doesn't matter which side the secondary alternator is connected to.
<snip>
Anyway, hope this hasn't been to confusing. This forum and the
Aeroelectric book have been an invaluable source of education for a
first-time builder.
Keep in mind that when the installation manual for
a system like Vertical Power =or= a Z-figure is
published, the ARCHITECTURE is being crafted to
meet certain design goals. The advice from Marc
embraces the design philosophy for a two-layered
electrical system as described in the notes for
Z-13/8 and illustrated in the companion drawing.
If your design goals are different and you are
satisfied with the failure mode effects for a
new configuration, then by all means . . .
I'm not trying to champion anyone's architectures
as being superior over any another . . . only the
idea that there are REASONS why things are hooked
up a particular way. Be sure you do the homework,
take the exam and are satisfied with the grade
before you shuffle things around.
Bob . . .
Message 10
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| Subject: | Re: starter engaged light |
At 01:35 PM 2/6/2010, you wrote:
>Good Afternoon 'Lectric Bob,
>
>I have a faint memory of a Cessna 210 having that sort of problem. I
>think that was the incident that prompted your old company to add
>starter engaged warning lights to their new production
>aircraft..Maybe around 1980 or so?
>
>Am I way off base here?
Not at all. Starter engaged lights were added to a number
of Beechcraft airframes as reports came in about damage
to starters and ring gears from stuck contactors. I
was struck by the notion that such a failure started a
chain of events that brought the airplane down. It
would be interesting to read the reports on the incident
if they can be retrieved.
Some years ago at OSH, some airshow performer reported
having "teased a starter contactor closed with the
g-loads of the performance" causing it it to weld and
ultimately do a lot of damage to the starter and
ring gear.
It's almost a sure bet that the contactor stuck during
cranking and was simply overlooked as the performer
was pre-occupied with the immediate task. G-loads
just don't close a starter contactor . . . they MIGHT
close an OPEN battery contactor . . . but who flies
around with a battery contactor open?
Bob . . .
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