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tomblejwas(at)yahoo.com Guest
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Posted: Mon Nov 18, 2013 11:59 am Post subject: Questions about Z-08 |
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Bob,
In the postings on running an alternator without a battery, you suggested I consider your new draft Z-08, which is buried in the long stream on "EXP 2 Bus workaround." The more I look at Z-08, the more I like the simplicity. It seems to meet most of my design goals, but answers to a few questions would be helpful.
1. What were your criteria in deciding to connect "Engine A" with a switch (1-3) and "Engine B" through a relay? By the way, what does the "K2" inside a green hexagon indicate on the relays?
2. You show both A and B connected to the "Motive Power Distribution Bus" through a single stud and bolt connector. I've read that lock washers do little to prevent a bolt from loosening. What do you do to give this type of connection the reliability one needs for critical components? Or can we? Wouldn't a different connection for A and B be prudent?
3. With respect to screw type connectors, what about the ground connection to the engine block? The high vibration of a running engine would seem to make these especially susceptible to loosening. What about two block connections going to two brass bolts through the firewall ground bus, or would this set up an electrically noisy ground loop?
4. I found your discussions about single versus dual batteries and properly maintaining batteries to be interesting. Since, as I mentioned in an earlier post, I've experienced a car battery shorting while I was driving. I accurately interpreted the limited info and stopped the car in a convenient place. Yes, the battery did not get the kind of attention you have suggested. But will the next owner of my plane be as conscientious as me? So, what is the downside of changing the DC Power Master from OFF/BAT/BAT+ALT to OFF/ALT/ALT+BAT, assuming that ALT FIELD can be disconnected if the alternator needs to be disconnected? If I did so, I would use an MGL Battery Monitor to see both voltage and current across the battery.
I appreciate your approach to challenging people like me to think through our decisions. Great forum? Thanks.
Tom
Thomas E. Blejwas
12 Via Entrada
Sandia Park, NM 87047
505-286-9294
tomblejwas(at)yahoo.com (tomblejwas(at)yahoo.com)
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nuckolls.bob(at)aeroelect Guest
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Posted: Mon Nov 18, 2013 4:09 pm Post subject: Questions about Z-08 |
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At 01:57 PM 11/18/2013, you wrote:
Quote: | Bob,
In the postings on running an alternator without a battery, you suggested I consider your new draft Z-08, which is buried in the long stream on "EXP 2 Bus workaround." The more I look at Z-08, the more I like the simplicity. It seems to meet most of my design goals, but answers to a few questions would be helpful.
1. What were your criteria in deciding to connect "Engine A" with a switch (1-3) and "Engine B" through a relay? |
the wires associated with "A" go mostly cold with
opening the battery contactor. The relay is a 'mini
contactor' located adjacent to the battery hence
the contactor control switch "B" on the panel
Quote: | By the way, what does the "K2" inside a green hexagon indicate on the relays? |
Artifact reference designators not yet germane to the
drawing.
Quote: |
2. You show both A and B connected to the "Motive Power Distribution Bus" through a single stud and bolt connector. I've read that lock washers do little to prevent a bolt from loosening. What do you do to give this type of connection the reliability one needs for critical components? Or can we? Wouldn't a different connection for A and B be prudent? |
The fuseblock connection is a stud that can
be secured with a locking nut . . . unlike headed
screws that engage threaded holes on popular terminal strips.
Quote: |
3. With respect to screw type connectors, what about the ground connection to the engine block? The high vibration of a running engine would seem to make these especially susceptible to loosening. What about two block connections going to two brass bolts through the firewall ground bus, or would this set up an electrically noisy ground loop? |
You could use two straps to the engine if you
wish . . . but some thread-locker on the single
bolt would secure it. Vibration is not an automatic
loosening force on a threaded fastener . . . it's
mass who's cg is not centered on the bolt that
provides loosening torque due to vibration. In this
case, a terminal on a soft piece of wire or braid
doesn't offer a significant mass.
Quote: |
4. I found your discussions about single versus dual batteries and properly maintaining batteries to be interesting. Since, as I mentioned in an earlier post, I've experienced a car battery shorting while I was driving. I accurately interpreted the limited info and stopped the car in a convenient place. Yes, the battery did not get the kind of attention you have suggested. But will the next owner of my plane be as conscientious as me? |
It should be noted in your POH/Maintenance documents.
There are numerous critical structures that receive
annual and/or pre-flight inspection. Adding the battery(ies)
to such a list isn't a far-fetched idea.
Quote: | So, what is the downside of changing the DC Power Master from OFF/BAT/BAT+ALT to OFF/ALT/ALT+BAT, assuming that ALT FIELD can be disconnected if the alternator needs to be disconnected? If I did so, I would use an MGL Battery Monitor to see both voltage and current across the battery. |
With the crowbar ov protection, you could
do the DC power switching as a simple two-pole,
on-off device. You can pull the breaker to
kill the altenrator field circuit.
Quote: |
I appreciate your approach to challenging people like me to think through our decisions. Great forum? Thanks.
|
I'm pleased that you find value in the exercise.
I believe that the attentive builder is a much
lower-risk pilot because he is privy to things
our flight instructors never told us . . . or were
included in the cookie-cutter POH.
Bob . . . [quote][b]
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l.p(at)talk21.com Guest
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Posted: Tue Nov 19, 2013 2:57 pm Post subject: Questions about Z-08 |
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Bob.
I have been unable to find any attachments pertaining to the Z-08 architecture that is being talked about.
Are you able to point me in the right direction please?
When I receive the aeroelectric-list in e-mail form there are never any attachments with them.
Am I missing something?
Any help much appreciated.
Patrick Elliott.
G-LGEZ
Quote: | "Attached are the preliminary sketches for my current
thoughts on an architecture for single battery, single
alternator, electrically dependent engine. This line of
thinking is being developed as an preferred alternative
to Z-19."
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________________________________ Message 4 _____________________________________
Time: 04:09:36 PM PST US
From: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>
Subject: Re: Questions about Z-08
At 01:57 PM 11/18/2013, you wrote:
Quote: | Bob,
In the postings on running an alternator without a battery, you
suggested I consider your new draft Z-08, which is buried in the
long stream on "EXP 2 Bus workaround." The more I look at Z-08, the
more I like the simplicity. It seems to meet most of my design
goals, but answers to a few questions would be helpful.
1. What were your criteria in deciding to connect "Engine A" with a
switch (1-3) and "Engine B" through a relay?
|
the wires associated with "A" go mostly cold with
opening the battery contactor. The relay is a 'mini
contactor' located adjacent to the battery hence
the contactor control switch "B" on the panel
Quote: | By the way, what does the "K2" inside a green hexagon indicate on
the relays?
|
Artifact reference designators not yet germane to the
drawing.
Quote: |
2. You show both A and B connected to the "Motive Power
Distribution Bus" through a single stud and bolt connector. I've
read that lock washers do little to prevent a bolt from
loosening. What do you do to give this type of connection the
reliability one needs for critical components? Or can we? Wouldn't
a different connection for A and B be prudent?
|
The fuseblock connection is a stud that can
be secured with a locking nut . . . unlike headed
screws that engage threaded holes on popular terminal strips.
Quote: |
3. With respect to screw type connectors, what about the ground
connection to the engine block? The high vibration of a running
engine would seem to make these especially susceptible to
loosening. What about two block connections going to two brass
bolts through the firewall ground bus, or would this set up an
electrically noisy ground loop?
|
You could use two straps to the engine if you
wish . . . but some thread-locker on the single
bolt would secure it. Vibration is not an automatic
loosening force on a threaded fastener . . . it's
mass who's cg is not centered on the bolt that
provides loosening torque due to vibration. In this
case, a terminal on a soft piece of wire or braid
doesn't offer a significant mass.
Quote: |
4. I found your discussions about single versus dual batteries and
properly maintaining batteries to be interesting. Since, as I
mentioned in an earlier post, I've experienced a car battery
shorting while I was driving. I accurately interpreted the limited
info and stopped the car in a convenient place. Yes, the battery
did not get the kind of attention you have suggested. But will the
next owner of my plane be as conscientious as me?
|
It should be noted in your POH/Maintenance documents.
There are numerous critical structures that receive
annual and/or pre-flight inspection. Adding the battery(ies)
to such a list isn't a far-fetched idea.
Quote: | So, what is the downside of changing the DC Power Master from
OFF/BAT/BAT+ALT to OFF/ALT/ALT+BAT, assuming that ALT FIELD can be
disconnected if the alternator needs to be disconnected? If I did
so, I would use an MGL Battery Monitor to see both voltage and
current across the battery.
|
With the crowbar ov protection, you could
do the DC power switching as a simple two-pole,
on-off device. You can pull the breaker to
kill the altenrator field circuit.
Quote: |
I appreciate your approach to challenging people like me to think
through our decisions. Great forum? Thanks.
|
I'm pleased that you find value in the exercise.
I believe that the attentive builder is a much
lower-risk pilot because he is privy to things
our flight instructors never told us . . . or were
included in the cookie-cutter POH.
Bob . . .
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nuckolls.bob(at)aeroelect Guest
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Posted: Wed Nov 20, 2013 11:57 am Post subject: Questions about Z-08 |
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At 04:57 PM 11/19/2013, you wrote:
Quote: | Bob.
I have been unable to find any attachments pertaining to the Z-08
architecture that is being talked about.
Are you able to point me in the right direction please?
When I receive the aeroelectric-list in e-mail form there are never
any attachments with them.
Am I missing something?
Any help much appreciated.
Patrick Elliott.
|
I'm still studying the options for reliable
attachment of illustrations to my postings. . .
In the mean time, the discussions that drive
the dialog on a new z-figure so far are
illustrated in a preliminary release of
figure Z-07. Seems Z-08 was recently used
in another discussion so I've renumbered
the drawing you can download at:
tinyurl.com/kbn6bys
Bob . . .
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teblejw
Joined: 19 Nov 2013 Posts: 14
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Posted: Thu Nov 21, 2013 7:06 pm Post subject: Questions about Z-08 |
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I haven't figured out how to easily insert my response with parts of the message to which I'm responding. Sorry for the difficulty this creates in understanding my comments.
1. Bob, do I understand correctly, that a simple switch is suitable for "Engine A" in Z-08 (now Z-07) because the switch will not usually be opened but rather the Main Battery Contactor will be opened instead?
Assuming that the Motive Bus is in my cockpit, I don't see why the relay for "Engine B" is in the engine compartment instead of in the cockpit, requiring two wires penetrating the firewall, instead of just one.
2 & 3. I appreciate your suggestions on securing stud-nut and engine-block connections. Thanks.
4. You suggested a double pole switch and the circuit breaker of the crowbar circuit could meet my needs, but this would allow the alternator and battery turned on together and then the alternator disconnected. But I want to keep the alternator connected while I disconnect the battery, as well as possibly disconnecting the alternator using the circuit breaker. Think I need a 2-10 switch for this. Correct?
Thanks.
Tom
Sent from my iPad
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nuckolls.bob(at)aeroelect Guest
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Posted: Thu Nov 21, 2013 7:21 pm Post subject: Questions about Z-08 |
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At 09:05 PM 11/21/2013, you wrote:
Quote: |
<tomblejwas(at)yahoo.com>
I haven't figured out how to easily insert my response with parts of
the message to which I'm responding. Sorry for the difficulty this
creates in understanding my comments.
|
Just hit 'reply' and the proposed outgoing
message will start off with a copy of the
message to which you are responding. Then
simply edit to insert your comments/questions
between line items of the subject matter.
Quote: | 1. Bob, do I understand correctly, that a simple switch is suitable
for "Engine A" in Z-08 (now Z-07) because the switch will not
usually be opened but rather the Main Battery Contactor will be
opened instead? Assuming that the Motive Bus is in my cockpit, I
don't see why the relay for "Engine B" is in the engine compartment
instead of in the cockpit, requiring two wires penetrating the
firewall, instead of just one.
|
The relay is a mini-battery contactor. It's purpose
is to disconnect a battery feeder as close as practical
to the battery. Engine A is not a battery feeder, Engine B
is. Hence, the disconnect relay at the battery.
Quote: | 2 & 3. I appreciate your suggestions on securing stud-nut and
engine-block connections. Thanks.
4. You suggested a double pole switch and the circuit breaker of
the crowbar circuit could meet my needs, but this would allow the
alternator and battery turned on together and then the alternator
disconnected. But I want to keep the alternator connected while I
disconnect the battery, as well as possibly disconnecting the
alternator using the circuit breaker. Think I need a 2-10 switch
for this. Correct?
|
Do you KNOW that you want to run the alternator
without a battery? This is not commonly done . . .
but it can be if you've conducted experiments to
explore the conditions under which you can operate
alternator only.
Even if you use the 2-10 as suggested, there are
no provisions for operating the altenrator without
also having a battery on line.
Bob . . .
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teblejw
Joined: 19 Nov 2013 Posts: 14
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Posted: Fri Nov 22, 2013 8:03 am Post subject: Questions about Z-08 |
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Bob,
I had previously selected to get a daily e-mail, so I must look at the HTML version of the messages to reply. When I do so, the message to which I am replying doesn't get copied into the new e-mail.
You stated under my #4: "Even if you use the 2-10 as suggested, there are no provisions for operating the alternator without also having a battery on line."
Assume I'm using an alternator that has a demonstrated ability to run without a battery (which I am) and that I am switched to Engine A. I change the switching so that, while the engine is running, I can open the contactor, e.g., middle position of my earlier suggestion of OFF/ALT/ALT+BAT. (If I need to disconnect the alternator while on ALT+BAT, I pull the circuit breaker in the crowbar circuit.) Doesn't this accomplish "operating the alternator without also having a battery on line"? I might also add switching to shut down the Main Power Distribution Bus.
Thanks for your patience with my questions.
Tom
Sent from my iPad
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ngeorge(at)continentalmot Guest
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Posted: Fri Nov 22, 2013 8:15 am Post subject: Questions about Z-08 |
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Tom -
Settings in your email application determine whether the original message is included in a reply...
Neal
=======================
Bob,
I had previously selected to get a daily e-mail, so I must look at the HTML version of the messages to reply. When I do so, the message to which I am replying doesn't get copied into the new e-mail.
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