Today's Message Index:
----------------------
1. 01:38 PM - Re: Z-13/8 design and operating philosophy (Robert L. Nuckolls, III)
2. 05:02 PM - 2-10 SWITCH - Can this be done? (Sam Hoskins)
3. 05:31 PM - Re: 2-10 SWITCH - Can this be done? (Dale Ensing)
4. 05:43 PM - Re: 2-10 SWITCH - Can this be done? (ROGER & JEAN CURTIS)
5. 06:28 PM - Re: 2-10 SWITCH - Can this be done? (Charlie England)
6. 06:37 PM - Re: 2-10 SWITCH - Can this be done? (Ken)
Message 1
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| Subject: | Z-13/8 design and operating philosophy |
At 11:37 AM 11/22/2008, you wrote:
>
>Bob,
>
>Thanks for updating our thinking. I too am going through this
>installation.
>
>Just to re-iterate the flow..
>
>Low voltage condition or other on primary alt, so...
>
>1. Switch main DC Power from Alt to Bat.
>2. Shed un-necessary load.
>2. Close the Alt E-Bus Feed switch.
>2. Switch main DC Power from Bat to Off.
>2. Switch on the Aux Alt SD-8 (After storing gum wrappers).
>4. Fly to a safe place.
That works. Just keep in mind that the whole idea
behind artfully maintained batteries and second
engine driven power sources is so that a "safe"
place is also a comfortable, convenient place for
effecting repairs to your machine. Further, all
the goodies on the panel cannot offer the
be-there-when-you-need-it utility of the stuff
in your flight bag.
Bob . . .
>Thanks
>
>-----Original Message-----
>From: owner-aeroelectric-list-server@matronics.com
>[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
>Robert L. Nuckolls, III
>Sent: Saturday, November 22, 2008 11:29 AM
>To: aeroelectric-list@matronics.com
>Subject: AeroElectric-List: Z-13/8 design and operating philosophy
>
><nuckolls.bob@cox.net>
>
>
> >>Hi Bob. Love your book.
>
> Thank you. I'm pleased that you find it a good value.
>
> >> On page 17-9 dealing with the SD-8 Alt, second column, second
> >> paragraph. I assume you would want to open the battery cont,
> >> close the E-bus alt feed switch and close the SD-8alt control
> >> relay (same as aux alt off/on swithch on Z-13 to on?)ONLY if the
> >> main alt fails as mentioned in the next para?
>
> Yes. That was the original intent. E-bus alt feed is closed before
> you turn off the battery master for the purpose of load shedding
> during battery-only operations. To avoid having the e-bus go down
> during the changeover, you turn on alternate-feed first, battery
> master off next. SD-8 can go on at any time in the sequence.
>
> Now assuming that an SD-8 is installed, it may be brought on
> to support e-bus loads thus saving all the battery's stored
> energy to support approach to landing were the battery master
> is turned back on and other equipment items are added to
> the system loads.
>
> >> Then will the SD-8 just be supplying pwr to charge the battery,
> >> or will it directly be supplying pwr to the essential bus because
> >> it is supplying more volts?
>
> It's a reasonable assumption that the battery was fully
> charged when the main alternator failed. There is no need
> for the SD-8 to "charge" the battery . . . it needs to support
> e-bus loads so as to NOT discharge the battery. As long as
> the SD-8 output remains above 12.7 volts or so, the battery
> will not contribute to operation of e-bus loads . . . i.e.
> is held in reserve.
>
> >> Someone told me he flies around with his SD-8 aux alt switch on
> >> all the time so there will never be a situation where there is no
> >> missing pwr to the field to get it to work. I don't think that is
> >> the correct way is it? With the SD-8, is it best to assume the
> >> endurance bus should not exceed about 7 amps (just under the 8)?
>
> He doesn't understand the equipment installed aboard
> his aircraft and has not crafted a Plan-A/Plan-B
> operating protocol based on understanding.
>
> His concerns for keeping the SD-8 "alive" are unfounded.
> First, the SD8 doesn't have an externally excited field.
> Second, assuming he has an active notification of low
> voltage (LV warning light) then the changeover from
> Plan-A to Plan-B after main alternator failure is
> a no-big-rush deal. The battery is sitting there
> substantially topped off and will run things nicely
> for some time . . . he could finish unwrapping his
> stick of gum and properly stow the wrapper before
> making the change.
>
> The SD-8 can be loaded to as much as 10A at cruise
> rpm without sagging below the 12.8 volt levels that
> begins to load the battery. There are no hard and fast
> "rules" about operations with the SD-8. Back before
> we installed SD-8's on a handy, vacated vacuum pump
> pad we sized AND MAINTAINED batteries for the purpose
> of supporting e-bus loads to meet design goals.
>
> If the builder's design goals call for battery-only
> endurance to be equal to fuel endurance, then the
> options for battery-only ops were constrained
> by trade-offs for battery size versus endurance
> loads.
>
> Once a second engine driven power source is added,
> one may use ALL the capability of this source
> without taxing the battery. However, let us
> assume that endurance loads need to be 12 amps.
> Okay, 10A from the SD-8 and 2A from the battery.
> This formula for achieving comfortable termination
> of flight is still quite attractive.
>
> You make your own rules based on load analysis and design
> goals for operating YOUR CHOICE of endurance mode accessories
> and planning on how you'll supply that energy.
>
> >> And finally, what is the best way to tie in dual LSEs and the
> >> SD-8 together? Thank you very much. David Buntin
>
> Run each ignition from the battery bus on it's
> own fuse. Run only one ignition during endurance
> mode operations.
>
> Bob . . .
>
>
>Checked by AVG - http://www.avg.com
>11/22/2008 6:59 PM
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 2
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| Subject: | 2-10 SWITCH - Can this be done? |
I am trying to configure a switch and am currently stumped.
I have two possible power inputs A or B.
I have two possible devices, C or D.
I want the three position switch to have the following conditions, with no
other combinations.
A powers C
B powers D
Off
Do you think this is possible with a single 2-10 Switch? I sure couldn't
figure it out. How else might I be able to accomplish it with only one
switch? Maybe a 4-10 (and where would I get one)?
This all has to do with redundant power inputs providing power to two sets
of fuel injectors.
Thanks,
Sam
Message 3
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| Subject: | Re: 2-10 SWITCH - Can this be done? |
Sam,
Can the center position be 'OFF'?
If so, a double pole/double throw switch will work if you use it to only sw
itch the positive leads and use a common for the negative for both connecti
ons. One pole, with throw in one direction, (say up) could give you the A p
ower to C and the other pole with the other direction throw (say down) woul
d give you B power to D.
Dale Ensing
----- Original Message -----
From: Sam Hoskins
To: Aerolectric List
Sent: Sunday, November 23, 2008 7:58 PM
Subject: AeroElectric-List: 2-10 SWITCH - Can this be done?
I am trying to configure a switch and am currently stumped.
I have two possible power inputs A or B.
I have two possible devices, C or D.
I want the three position switch to have the following conditions, with n
o other combinations.
A powers C
B powers D
Off
Do you think this is possible with a single 2-10 Switch? I sure couldn't
figure it out. How else might I be able to accomplish it with only one sw
itch? Maybe a 4-10 (and where would I get one)?
This all has to do with redundant power inputs providing power to two set
s of fuel injectors.
Thanks,
Sam
Message 4
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| Subject: | 2-10 SWITCH - Can this be done? |
I am trying to configure a switch and am currently stumped.
I have two possible power inputs A or B.
I have two possible devices, C or D.
I want the three position switch to have the following conditions, with no
other combinations.
A powers C
B powers D
Off
Do you think this is possible with a single 2-10 Switch? I sure couldn't
figure it out. How else might I be able to accomplish it with only one
switch? Maybe a 4-10 (and where would I get one)?
This all has to do with redundant power inputs providing power to two sets
of fuel injectors.
Thanks,
Sam
You can accomplish this using a 2-10 switch connected as follows: A to 2, B
to 5, C to 1, D to 6.
A simple dpdt center off switch can be also wired for this circuit.
Roger
Message 5
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| Subject: | Re: 2-10 SWITCH - Can this be done? |
ROGER & JEAN CURTIS wrote:
>
> I am trying to configure a switch and am currently stumped.
>
> I have two possible power inputs A or B.
>
> I have two possible devices, C or D.
>
> I want the three position switch to have the following conditions,
> with no other combinations.
>
> A powers C
> B powers D
> Off
>
> Do you think this is possible with a single 2-10 Switch? I sure
> couldn't figure it out. How else might I be able to accomplish it
> with only one switch? Maybe a 4-10 (and where would I get one)?
>
> This all has to do with redundant power inputs providing power to two
> sets of fuel injectors.
>
> Thanks,
>
> Sam
>
> * *
> *You can accomplish this using a 2-10 switch connected as follows: A to 2, B
to 5, C to 1, D to 6.*
> * *
> *A simple dpdt center off switch can be also wired for this circuit.*
> * *
> *Roger*
Is it acceptable that one switch failure takes out both systems?
Message 6
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| Subject: | Re: 2-10 SWITCH - Can this be done? |
I never understood why guys like this sort of thing. It means you do NOT
have redundant systems since one switch failure can fail both sources of
power.
FWIW my engine continues to run if I energize both injection systems and
feed twice the normal fuel to it. Definitely rich but not a show stopper.
Ken
Sam Hoskins wrote:
> I am trying to configure a switch and am currently stumped.
>
> I have two possible power inputs A or B.
>
> I have two possible devices, C or D.
>
> I want the three position switch to have the following conditions, with
> no other combinations.
>
> A powers C
> B powers D
> Off
>
> Do you think this is possible with a single 2-10 Switch? I sure
> couldn't figure it out. How else might I be able to accomplish it with
> only one switch? Maybe a 4-10 (and where would I get one)?
>
> This all has to do with redundant power inputs providing power to two
> sets of fuel injectors.
>
> Thanks,
>
> Sam
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