Matronics Email Lists Forum Index Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
 
 Get Email Distribution Too!Get Email Distribution Too!    FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

One battery/two alternators IFR z-diagram

 
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> AeroElectric-List
View previous topic :: View next topic  
Author Message
mburbidg(at)gmail.com
Guest
PostPosted: Wed Dec 18, 2019 3:51 pm    Post subject: One battery/two alternators IFR z-diagram Reply with quote
I’m building an RV-14A. The panel will be IFR capable, Garmin G3X system. The ignition system will be dual PMAGs.
 
I’d like to go with a single battery, two alternator system. B&C 60 Amp and B&C 20 Amp alternators.
 
I’d prefer the electrical system be as simple as is practical. Z-13/20 looks to be about what I want, but I’ve heard this is no longer a recommended architecture. (I saw one post that said it had been excommunicated. 😊)
 
What is there a recommended replacement architecture for the z-13/20?
 
Z-12 also appears to fit the bill.
 
Thanks,
Michael-

- The Matronics AeroElectric-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?AeroElectric-List
Back to top
mburbidg(at)gmail.com
Guest
PostPosted: Wed Dec 18, 2019 6:27 pm    Post subject: One battery/two alternators IFR z-diagram Reply with quote
After doing some reading on the FAQ list, it looks like I should consider the Z-13/8 with the Z-25 excitation mod, or else the Z-14. I think I also now understand one of the drawbacks of Z-12 architecture is if the battery contactor fails, both alternators go offline.
 
Michael-
 
From: "owner-aeroelectric-list-server(at)matronics.com" <owner-aeroelectric-list-server(at)matronics.com> on behalf of Michael Burbidge <mburbidg(at)gmail.com>
Reply-To: "aeroelectric-list(at)matronics.com" <aeroelectric-list(at)matronics.com>
Date: Wednesday, December 18, 2019 at 3:56 PM
To: "aeroelectric-list(at)matronics.com" <aeroelectric-list(at)matronics.com>
Subject: AeroElectric-List: One battery/two alternators IFR z-diagram

 

I’m building an RV-14A. The panel will be IFR capable, Garmin G3X system. The ignition system will be dual PMAGs.
 
I’d like to go with a single battery, two alternator system. B&C 60 Amp and B&C 20 Amp alternators.
 
I’d prefer the electrical system be as simple as is practical. Z-13/20 looks to be about what I want, but I’ve heard this is no longer a recommended architecture. (I saw one post that said it had been excommunicated. 😊)
 
What is there a recommended replacement architecture for the z-13/20?
 
Z-12 also appears to fit the bill.
 
Thanks,
Michael-

- The Matronics AeroElectric-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?AeroElectric-List
Back to top
rick(at)beebe.org
Guest
PostPosted: Thu Dec 19, 2019 2:11 pm    Post subject: One battery/two alternators IFR z-diagram Reply with quote
I'm not sure that's true. I have the same basic setup. Single battery, two alternators and I used Z-12. The PMAGs are self-contained so you don't have an electrically dependent ignition system. I'm using an SB18-14 regulator for the second alternator so both can just stay on. I have a Garmin G-5 as my backup instrument and I installed the battery on it so in the unlikely event of a complete electrical failure I'll have 45 minutes or so to get the plane on the ground.
--Rick
On 12/18/2019 9:26 PM, Michael Burbidge wrote:

Quote:

After doing some reading on the FAQ list, it looks like I should consider the Z-13/8 with the Z-25 excitation mod, or else the Z-14. I think I also now understand one of the drawbacks of Z-12 architecture is if the battery contactor fails, both alternators go offline.
 
Michael-
 
From: "owner-aeroelectric-list-server(at)matronics.com" (owner-aeroelectric-list-server(at)matronics.com) <owner-aeroelectric-list-server(at)matronics.com> (owner-aeroelectric-list-server(at)matronics.com) on behalf of Michael Burbidge <mburbidg(at)gmail.com> (mburbidg(at)gmail.com)
Reply-To: "aeroelectric-list(at)matronics.com" (aeroelectric-list(at)matronics.com) <aeroelectric-list(at)matronics.com> (aeroelectric-list(at)matronics.com)
Date: Wednesday, December 18, 2019 at 3:56 PM
To: "aeroelectric-list(at)matronics.com" (aeroelectric-list(at)matronics.com) <aeroelectric-list(at)matronics.com> (aeroelectric-list(at)matronics.com)
Subject: One battery/two alternators IFR z-diagram

 

I’m building an RV-14A. The panel will be IFR capable, Garmin G3X system. The ignition system will be dual PMAGs.
 
I’d like to go with a single battery, two alternator system. B&C 60 Amp and B&C 20 Amp alternators.
 
I’d prefer the electrical system be as simple as is practical. Z-13/20 looks to be about what I want, but I’ve heard this is no longer a recommended architecture. (I saw one post that said it had been excommunicated. 😊)
 
What is there a recommended replacement architecture for the z-13/20?
 
Z-12 also appears to fit the bill.
 
Thanks,
Michael-



- The Matronics AeroElectric-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?AeroElectric-List
Back to top
mburbidg(at)gmail.com
Guest
PostPosted: Thu Dec 19, 2019 5:24 pm    Post subject: One battery/two alternators IFR z-diagram Reply with quote
Hi Rick,
 
I got the information from a thread in the aeroelectric FAQ: http://www.homebuiltexperimental.com/UsefulDocs/AeroElectric-List_FAQ.pdf
 
It looks like you’re set because you have self-powering Pmags and backup power on you G5. But it does seem to me, according to this thread, that a failed contactor can result in total power loss using the z-12 architecture.
 
Michael-
 
p.s. Here’s the text. Perhaps I’ve misinterpreted this.
 
---------
Re: Loss of Batt Contactor in Fig Z-12 >Hi Bob, In numerous places you say "alternators don't run well without a battery"...What exactly does this mean for Z-12 architecture if you lose your battery contactor? Can I assume that in Z-12, the primary B&C 60A alt. and backup SD-20 alternator would both be useless under this failure scenario and you would be left with only your essential bus powered off the battery? A Yes. That is why the All Electric Airplane on a Budget architecture is so attractive. The SD-8 is inexpensive, light, bypasses the battery contactor and supplies enough snort to run LOTS of goodies. Now, just because the battery contactor fails to do the designed function doesn't mean the alternator(s) quit. Remember, an alternator needs a source of field voltage which is the same bus that the alternator powers. IF . . . you hit the bus with a high inrush load (landing light, certainly a hydraulic pump, etc) with no battery to fill in the gap for a few tens of milliseconds, the bus could sag sufficiently to starve the field supply which drops the bus voltage which starves the field supply even more. The effect is precipitous. The alternator quits and without a battery, it doesn't come back. Even if the alternator says on line, loss of battery always degrades stability of the voltage regulator and the bus voltage jumps around more. Filtering action of the battery is lost too and the bus become noisier. Sooooo . . . if one has managed to get an STC to put an SD-20 on a certified ship like a C210 or Bonanza, the next thing I would do is get an STC to add an aux battery. Once you go the dollars and weight to put the SD-20 on an amateur built aircraft, I'd go for the extra battery too . . .whether it's an aux battery in parallel with the main battery al la Z-12 or a dual-battery/dual-alternator installation like Figure Z-14 (even if the second battery is small like we discussed earlier). >If that is indeed the case, wouldn't the slightly more complicated and marginally more expensive Z-14 be MUCH more reliable/redundant as either alternator would be capable of running off either battery in case of a failed contactor... Worded another way: If you're already planning a dual alternator (B&C 60A + SD-20) system, is there any reason to go with the Z-12 architecture over the Z-14 architecture if you can live with the small increases in added weight, cost and complexity of Z-14... A You got it. >On another note, I plan on having initially one electronic ignition and one mag...eventually possibly going to dual electronic ignition after using the mags I already have. Would adding an aux battery & bus (to power the second electronic ign) to Z-12 be a relatively easy modification or do you think it would make more sense to just start out with the dual alt/dual batt/split bus Z-14 system? A If you don't mind the dollars and weight budget, the Z-14 or Z-14A architecture will provide the highest margin of comfort. But if you're going to use up both mags before you put a second electronic ignition on, you may be very close to selling the airplane before you need to upgrade the system . . . perhaps Z-13 has a good chance of supplying your needs for many hundreds of hours. When the second electronic ignition goes in, add a small aux battery al la Z-30. Don't get me wrong, the SD-20 is a fine piece of machinery but if you're making $tradeoffs$ between what useful goodies you're planning to put on the panel and the ability to shovel lots of electrons, maybe your best return on investment would be with the smaller second alternator. Bob . . . -------
---------
 
 
From: "owner-aeroelectric-list-server(at)matronics.com" <owner-aeroelectric-list-server(at)matronics.com> on behalf of Rick Beebe <rick(at)beebe.org>
Reply-To: "aeroelectric-list(at)matronics.com" <aeroelectric-list(at)matronics.com>
Date: Thursday, December 19, 2019 at 2:16 PM
To: "aeroelectric-list(at)matronics.com" <aeroelectric-list(at)matronics.com>
Subject: Re: AeroElectric-List: One battery/two alternators IFR z-diagram

 

I'm not sure that's true. I have the same basic setup. Single battery, two alternators and I used Z-12. The PMAGs are self-contained so you don't have an electrically dependent ignition system. I'm using an SB18-14 regulator for the second alternator so both can just stay on. I have a Garmin G-5 as my backup instrument and I installed the battery on it so in the unlikely event of a complete electrical failure I'll have 45 minutes or so to get the plane on the ground.
--Rick
On 12/18/2019 9:26 PM, Michael Burbidge wrote:
Quote:

After doing some reading on the FAQ list, it looks like I should consider the Z-13/8 with the Z-25 excitation mod, or else the Z-14. I think I also now understand one of the drawbacks of Z-12 architecture is if the battery contactor fails, both alternators go offline.
 
Michael-
 
From: "owner-aeroelectric-list-server(at)matronics.com" (owner-aeroelectric-list-server(at)matronics.com) <owner-aeroelectric-list-server(at)matronics.com> (owner-aeroelectric-list-server(at)matronics.com) on behalf of Michael Burbidge <mburbidg(at)gmail.com> (mburbidg(at)gmail.com)
Reply-To: "aeroelectric-list(at)matronics.com" (aeroelectric-list(at)matronics.com) <aeroelectric-list(at)matronics.com> (aeroelectric-list(at)matronics.com)
Date: Wednesday, December 18, 2019 at 3:56 PM
To: "aeroelectric-list(at)matronics.com" (aeroelectric-list(at)matronics.com) <aeroelectric-list(at)matronics.com> (aeroelectric-list(at)matronics.com)
Subject: AeroElectric-List: One battery/two alternators IFR z-diagram

 

I’m building an RV-14A. The panel will be IFR capable, Garmin G3X system. The ignition system will be dual PMAGs.
 
I’d like to go with a single battery, two alternator system. B&C 60 Amp and B&C 20 Amp alternators.
 
I’d prefer the electrical system be as simple as is practical. Z-13/20 looks to be about what I want, but I’ve heard this is no longer a recommended architecture. (I saw one post that said it had been excommunicated. 😊)
 
What is there a recommended replacement architecture for the z-13/20?
 
Z-12 also appears to fit the bill.
 
Thanks,
Michael-



- The Matronics AeroElectric-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?AeroElectric-List
Back to top
cluros(at)gmail.com
Guest
PostPosted: Fri Dec 20, 2019 3:46 pm    Post subject: One battery/two alternators IFR z-diagram Reply with quote
Speaking strictly for my applications Bob (VFR and IFR AB, some of which have electrically dependent engines), I totally agree. My ideal system is not bulletproof or dispatcheable after one or more failures. My ideal system is as simple and cheap as possible, while allowing for comfortable termination of flight after a failure.
As soon as the bus voltage sags below 13.8v, red lights start flashing in multiple places. Once this happens there is a checklist to follow in each airplane, and manually changing the alternator switch from main to aux is no big deal. 20A is sufficient for comfortable termination of flight, or even load shedding and continuation of flight in many circumstances.
I like the idea of an endurance bus, but have never implemented it because the added complexity was not justified by the benefits.

On Fri, Dec 20, 2019, 15:09 Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:

Quote:
Quote:
 
What is there a recommended replacement architecture for the z-13/20?

  Z13/8 was crafted with the notion of offering
  a robust (meaning unlimited electrical endurance
  in the alt-out mode) plan-b for loss of main alternator
  assuming running loads can be reduced to 10A
  or less . . . which is the capability of
  the SD8.

  I fiddled with the idea of a Z13/20 waayyy
  back when . . . at time when the operating
  philosophy for the SD20 called for b-lead
  current sensing and cockpit indications
  for reducing load to values at or below
  the 'rated' output of the alternator.

  This made the FAA happy . . . but in retrospect
  was totally unnecessary. The SD20 has
  a pedigree based on a 40A, automotive,
  belt driven alternator (B&C's L40).
  In a Lycoming installation, it runs
  at 10KRPM or better, may indeed be expected
  to produce 40A under some conditions
  and is belt-driven which produces significant
  axial loading on the bearings.

  As an SD20, it's DERATED not for any physical
  design limits . . . but because on the
  vacuum pump pad it isn't driven at much
  more than 3900 rpm. So in fact, you cannot
  physically 'overload' this alternator to the
  extend that functionality is at risk.
  Its output sags and it's physically incapable
  of producing the same output as the mother-machine
  just 'cause it's not turning fast enough.

  In years since, materials and processes for
  the raw-stock have improved such that the
  SD20 is now rated at more than 20A on a
  pad drive.

  The Z13/8 philosophy for minimizing running
  loads while under standby power is not
  especially valid for EITHER a Z12 or Z13/20
  application.

  So as mentioned in my post of a few mintues
  ago, I think I'm going to revise Z-12 to (1)
  remove the Endurance Bus and (2) replace the
  standby regulator with something simple and
  cheap. The best indicator of loading the standby
  alternator too hard is depression of bus
  voltage below 13.0 volts. Given the number
  of voltmeters in most airplanes today, the
  value of a over-current, under-voltage sensing
  regulator on the standby system seems something
  of overkill.

  Modern electronics and lighting have made it
  possible to craft even an IFR capable machine
  with running loads below the output capability
  of a pad-driven SD20.

  Have I overlooked anything here? Considered
  critical review is most welcome . . .


  Bob . . .


- The Matronics AeroElectric-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?AeroElectric-List
Back to top
rick(at)beebe.org
Guest
PostPosted: Sat Dec 21, 2019 8:35 pm    Post subject: One battery/two alternators IFR z-diagram Reply with quote
On 12/20/2019 7:15 PM, user9253 wrote:
Quote:


So as mentioned in my post of a few mintues
ago, I think I'm going to revise Z-12 to (1)
remove the Endurance Bus and (2) replace the
standby regulator with something simple and
cheap.
> Great idea Bob. Simpler is better.

Quote:
Many VFR sport planes do not even need a standby alternator.
Now if we could just convince builders to NOT install an avionics switch.

--------
Joe Gores

I'm sold on both counts. I'm turning my traditional 6-pack VFR GlaStar
into an all-glass IFR plane and I'm wiring it using Z-12 with no
endurance bus and no avionics master. I repurposed its hole for the
pitot heat switch.

--Rick

- The Matronics AeroElectric-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?AeroElectric-List
Back to top
Display posts from previous:   
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> AeroElectric-List All times are GMT - 8 Hours
Page 1 of 1

 
Jump to:  
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