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Z-13/20 questions

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jonlaury

Joined: 06 Nov 2006
Posts: 336

Posted: Wed Jan 20, 2010 10:53 am Post subject: Z-13/20 questions

I've decided that Z13/20 works best for my all electric ship and I have a couple of questions:



For aesthetic and robustness reasons, I'm married to the Honeywell AML 34  15A switches. But they only come in DPST.



So for the Ebus-Alt and Master Power switches, could I use one pole for the respective VR Bus terminal and one for the respective contactor? I see the reason for the DPDT switch in the drawing is to allow shutting down the respective alternator without disconnecting the respective bus from the remaining alternator. But couldn't that be accomplished by placing the Alt Field breaker between the DPST switch and the VR to use as a 'switch' to shutdown the offending alternator without opening the respective contactor?



In the drawing, why is the VR bus circuit both fuselinked AND CB'd?

Why fuselink the battery bus-Ebus wire if it's (*) 6" or less?  



Thanks,

John

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Jan 20, 2010 2:37 pm Post subject: Z-13/20 questions

At 12:53 PM 1/20/2010, you wrote:

 	  Quote: 	
		  



I've decided that Z13/20 works best for my all electric ship and I 

have a couple of questions:



For aesthetic and robustness reasons, I'm married to the Honeywell 

AML 34  15A switches. But they only come in DPST.



So for the Ebus-Alt and Master Power switches, could I use one pole 

for the respective VR Bus terminal and one for the respective 

contactor? I see the reason for the DPDT switch in the drawing is to 

allow shutting down the respective alternator without disconnecting 

the respective bus from the remaining alternator. But couldn't that 

be accomplished by placing the Alt Field breaker between the DPST 

switch and the VR to use as a 'switch' to shutdown the offending 

alternator without opening the respective contactor?



In the drawing, why is the VR bus circuit both fuselinked AND CB'd?

Why fuselink the battery bus-Ebus wire if it's (*) 6" or less?


	


     We've had a number of conversations about Z-13/20

     since it was first conceived and published. About

     two years ago I confessed that it wasn't a good

     idea and pulled it from the suite of drawings offered

     on the website and the book.



     It's my recommendation you consider Z-13/8 as the

     lightest, simplest, and least expensive approach

     to a highly failure tolerant system for light

     aircraft. If you MUST go with the SD20 alternator,

     then some variant on full-up, dual systems with

     crossfeed is recommended.



     Switching philosophy is a personal choice. Suggestions

     made in the Z-figures are the product of 20+ years

     of sifting simple ideas to meet design goals.

     I'm not suggesting that the Z-figures are "golden",

     only that they satisfied the design goals. If your

     goal is to use the AML switches, you can add more

     switches and give up the convenience and operational

     safeguards offered by the two pole, progressive

     transfer devices . . . or have the AML operate relay(s)

     as needed to keep the functionality. Finally,

     as you've suggested, you can start shuffling things

     around . . . but it's no longer a Z-figure.



     Bob . . .

jonlaury

Joined: 06 Nov 2006
Posts: 336

Posted: Wed Jan 20, 2010 8:54 pm Post subject: Re: Z-13/20 questions

Arrgh, Bob.



After all my rumination to decide and you say "by the way that system sucks"? You're killing me!('')



As you probably gathered from the Silicone Goo post, I already have the aux alternator. It's 40 amps, same basic unit as B&C. It's overkill but the penalty is just 1.5 #'s and I do need some of the capacity.



I'm choosing Z-13 over Z-19 for 6#'s less weight and unlimited electrical endurance at the expense of marginally less reliability than 2 batteries.



But I don't see an advantage to a cross-feed contactor in Z-13, or where it would go. It seems that Z-13 has everything that I would need. What did you have in mind?



I still don't understand the thinking of having a fuselink and fuse/CB on the  same circuit ala the battery bus to e bus run. Otherwise I feel that Z-13/8(40) and I will get along fine.



John

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Jan 21, 2010 5:49 am Post subject: Z-13/20 questions

At 10:54 PM 1/20/2010, you wrote:

 	  Quote: 	
		  



Arrgh, Bob.



After all my rumination to decide and you say "by the way that 

system sucks"? You're killing me!('')


	


    Sorry 'bout that . . . but it was not well thought

    out. Shouldn't have published it without more thought.



 	  Quote: 	
		  As you probably gathered from the Silicone Goo post, I already have 

the aux alternator. It's 40 amps, same basic unit as B&C. It's 

overkill but the penalty is just 1.5 #'s and I do need some of the capacity.


	


 	  Quote: 	
		  I'm choosing Z-13 over Z-19 for 6#'s less weight and unlimited 

electrical endurance at the expense of marginally less reliability 

than 2 batteries.



But I don't see an advantage to a cross-feed contactor in Z-13, or 

where it would go. It seems that Z-13 has everything that I would 

need. What did you have in mind?


	


    Only completely independent systems have/need

    cross-feed capability. If you have the ability

    to drive two alternators and get rated output

    from them and your second alternator is hefty,

    then perhaps Z-14 is a better bet with two smaller

    batteries.

 	  Quote: 	
		  I still don't understand the thinking of having a fuselink and 

fuse/CB on the  same circuit ala the battery bus to e bus run. 

Otherwise I feel that Z-13/8(40) and I will get along fine.


	


   The only instance I recall using a fusible link in series

   with a breaker is on systems that feature fuse blocks AND

   crowbar OV protection. The only circuit protection on the

   panel is the 5A breaker made necessary by the crowbar ov

   system EXTENSION of the fuse bus up to the breaker calls

   for ROBUST circuit protection that won't open when the breaker

   trips.



   Where do you see a fusible link, fuse and cb on the same

   line in my drawings?

   Bob . . .

user9253

Joined: 28 Mar 2008
Posts: 1908
Location: Riley TWP Michigan

Posted: Thu Jan 21, 2010 8:15 am Post subject: Re: Z-13/20 questions

John,

Here are some more AML rocker switches if you are interested:

http://tinyurl.com/yzesmjo

And the data sheet:

http://content.honeywell.com/sensing/prodinfo/manual/catalog/c30030.pdf

Joe

_________________
Joe Gores

jonlaury

Joined: 06 Nov 2006
Posts: 336

Posted: Thu Jan 21, 2010 9:20 am Post subject: Re: Z-13/20 questions

Bob,



With silicone goo all over the 2nd alternator, 2 smaller batteries never crossed my mind. Looking forward to exploring that.



Re fuselinks and fuses/cb's on same line, the Z-13/8 version that I have shows that condition on the battery bus feed to the E-bus alt feed switch to the Ebus.



John



*************



Joe,



Thanks for the links. I'd looked at the AML 24 series , but dismissed them because the contact rating is for just 2 amps resistive (at) 24vdc.



http://sensing.honeywell.com/index.cfm/ci_id/141354/la_id/1/document/1/re_id/0



I'm not sure if this matters for operating contactors, or some of the other circuits in the Z architectures. I thought that I would have more flexibility with higher amp rated switches at the expense of an extra switch or two, because of single throw limitation.



Thanks

John

flyboybob1(at)gmail.com
Guest

Posted: Fri Jan 22, 2010 3:19 pm Post subject: Z-13/20 questions

Bob,



You wrote regarding Z13/20:  "Shouldn't have published it"



I too had made the decision to use multiple alternators based on my

electrically depandent engine,  I also have a design goal of no single point

of failure in the electrical system, so I decided on a light weight version

of Z14 for basic power distribution and an overlay of Z13 for main-bus and

E-bus.  I like Z13 for it's simplicity of operation, and Z14 for it's

indepandant power supply.  I submitted a wiring diagram that you stated you

were "praying over" a while back.  Seems like I have fallen into an area

similar to John <jonlaury(at)impulse.net> so I thought I would probe you again.

In your last post regarding my inquiry you said to use Z9 which seemed to

address other issues.  I figured you were just busy with moving  so I didn't

pursue the issue at the time.  Since John has asked a very similar question,

perhaps you could give us your opinion of using Z14 for battery bus, starter

and alternator, and then a main-bus and e-bus from there as with Z13.  I

like this appriach because the inflight troubleshooting is eliminated.

Using a low voltage checklist you can get to stable operation in a few

seconds after a low voltage envent is detected on either battery bus.  You

can see my wiring diagram at: http://kr.flyboybob.com/kr2/wd0004.htm.



Thanks for all you do to help us understand what trade offs we play in

making our electrical decisions.



Regards,

Bob Lee

N52BL  KR2

Suwanee, GA  USA

92% done only 67% to go!

user9253

Joined: 28 Mar 2008
Posts: 1908
Location: Riley TWP Michigan

Posted: Sat Jan 23, 2010 8:34 pm Post subject: Re: Z-13/20 questions

http://kr.flyboybob.com/kr2/wd0004_files/wd0004_frames.htm

Bob Lee,



The fuel injector relay is missing a wire on the common contact.



  There are two current paths between Battery Bus 2 and the Endurance Bus, one through a diode and one through a 10 amp fuse.  Since the second path through the fuse does not have a diode in it, current from Battery Bus 1 can flow to Battery Bus 2.



  The ground power relay coil needs to have a diode in series with it to protect against reverse polarity.  What is the purpose of the 5 amp breaker with two wires going to the ground power plug?



As drawn, the "Cross Contactor" is energized, but the indicator light is off.  Did you intend that terminal 3 of the Cross Contactor Switch be grounded?



I suggest that the top half of the "Cross Contactor" switch control the ground side of the fuel injector relay coil instead of the hot side, thus minimizing hot wires inside of the cockpit.   Of course that change would require changing the indicator light circuit too.

Joe

_________________
Joe Gores

flyboybob1(at)gmail.com
Guest

Posted: Sun Jan 24, 2010 5:30 am Post subject: Z-13/20 questions

Joe,



Thank you very much for your comments (see response below), you've helped me

improve my design.  I made changes to the power distribution schematic and

reposted the dirgram at http://kr.flyboybob.com/kr2/wd0004.htm

Regards,

Bob Lee

N52BL  KR2

Suwanee, GA  USA

92% done only 67% to go!

Joe Gores (user9253 [fran4sew(at)banyanol.com]) wrote:



The fuel injector relay is missing a wire on the common contact.



	<< The jumper from that contact to the relay coil was omitted.  It's been

fixed. >>



  There are two current paths between Battery Bus 2 and the Endurance Bus,

one through a diode and one through a 10 amp fuse.  Since the second path

through the fuse does not have a diode in it, current from Battery Bus 1 can

flow to Battery Bus 2.



	<< Years ago I scored a bunch of AN-3160 circuit breaker switches for a

buck each at Oshkosh.  The symbol you identified as a fuse is in reality a

guarded circuit breaker switch. As the note on the diagram states it is the

E-bus alternate feed path.  If the E-bus goes dark, open the guard and flip

the alternate feed breaker.  If the primary path E-bus feed through the

diode is dark I don't see the backfeed issue as problematic. >>



The ground power relay coil needs to have a diode in series with it to

protect against reverse polarity.



	<< I just looked at Z-31B again and realized what I did.  I put the diode

across the relay like a battery contactor. It's been fixed >>



What is the purpose of the 5 amp breaker with two wires going to the ground

power plug?



	<< The breaker is in the ground path to the over voltage crowbar.  The

ground symbol was up in the crowbar area.  I moved it down to the circuit

breaker. I also changed the breaker to 2 amp rating per Z-31B. >>



As drawn, the "Cross Contactor" is energized, but the indicator light is

off.  Did you intend that terminal 3 of the Cross Contactor Switch be

grounded?



I suggest that the top half of the "Cross Contactor" switch control the

ground side of the fuel injector relay coil instead of the hot side, thus

minimizing hot wires inside of the cockpit.   Of course that change would

require changing the indicator light circuit too.



	<< The relay is actually the starter realy that coincidently controls the

fuel injection cold start circuit.  That is why it is on the hot side.  I

changed the cross connect light circuit to get it's power from the cross

connect contactor. >>

mrspudandcompany(at)veriz
Guest

Posted: Sun Jan 24, 2010 6:49 am Post subject: Z-13/20 questions

Thank you very much for your comments (see response below), you've helped me

improve my design.  I made changes to the power distribution schematic and

reposted the dirgram at http://kr.flyboybob.com/kr2/wd0004.htm

Regards,

Bob Lee

Bob,



In taking a quick look at your diagram, it appears that your cross feed

contactor will not work.  You seem to have both sides of the contactor tied

together and through a switch (start/xfeed switch) to ground.  When you

power this up a diode will vaporize.



I haven't looked over the rest of the drawing.



Roger

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Jan 24, 2010 8:10 am Post subject: Z-13/20 questions

AeroElectric-List message posted by: "Bob Lee" <flyboybob1(at)gmail.com>



Bob,



You wrote regarding Z13/20:  "Shouldn't have published it"



     Yes . . . it was not a well considered or tested

     recipe for success at the time of publication.



I too had made the decision to use multiple alternators based on my

electrically dependent engine,  I also have a design goal of no single point

of failure in the electrical system, so I decided on a light weight version

of Z14 for basic power distribution and an overlay of Z13 for main-bus and

E-bus.  I like Z13 for it's simplicity of operation, and Z14 for it's

independent power supply.



      There is risk associated with cherry-picking features

      from multiple recipes for the purpose of crafting a new

      recipe. It begs to be sifted for the effects of single

      failures (if flight for hire or transport, double failures

      along with probability analysis). Finally, the value of

      a new recipe is traded against existing recipes for addressing

      design goals not easily addressed in existing recipes. Z13/20

      was crafted and published without due diligence to these

      processes.



I submitted a wiring diagram that you stated you were "praying over"

a while back.  Seems like I have fallen into an area similar to

John <jonlaury(at)impulse.net> so I thought I would probe you again.



In your last post regarding my inquiry you said to use Z9 which seemed to

address other issues.



     Z-9 was crafted to meet design goals offered by "Mr. Corvair

     Engines" and fine tuned to adopt legacy design goals for failure

     modes. Conversion packages for the VW would have similar electrical

     system issues as the Corvair. You've stated that you found Z13/8,

     Z-14 and I guess Z-9 inadequate to your design goals.



     Cruising your website offers and impression that your

     goals for the KR-2 are indeed extra-ordinary. I didn't

     have time to read all the details so correct me if I'm

     wrong . . . this is a highly experimental endeavor that

     uses a lot of designs and hardware from projects never

     before assembled in this combination on a single airplane . . .

     much less multiple airplanes.



     Not necessarily a "bad" idea. But it does suggest a long

     list of risks requiring a "fine-tuning" of the airplane before

     you can confidently launch on a series of long distance

     travels with high probability of care-free arrivals.

     This is not your grandpa's C-170. It will certainly test

     your skills as a multi-discipline, flight test engineer.



     From one who has participated in the flight testing and

     product development of very complex airplanes

     I can only caution that $time$ to test, de-bug, and

     re-design seems to go up with the exponentially

     with the number of "new ingredients" in your recipe

     for success. Of course, given the unforgiving nature

     of the aerodynamically supported machines, one hopes

     that new de-bugging tasks are not displaced by

     issues involving bent airplanes and/or broken bods.



You can see my wiring diagram at: http://kr.flyboybob.com/kr2/wd0004.htm



     This is a busy electrical system. It has virtually

     no legacy of design goals that birthed the Z-figures and

     is essentially a scratch design. It would take hours

     of conversation and mulling features to first understand

     why the system is designed this way and then ratify

     the ideas or suggest alternatives. This is something

     I cannot offer right now as I have more than I can

     handle for consulting clients already on the schedule.



     My best suggestion is that you adopt Z-13/8 as a

     system that gets its reliability from

     simplicity. My sense is that you are going to have

     a great deal on your plate getting other, much

     more risky details ironed out. Electrical SYSTEM

     failures are VERY SELDOM root cause of an unplanned

     arrival with the earth. Z-13/8 with a well maintained

     battery offers a rock solid energy generation and

     delivery platform. "Stirring" the recipe only adds

     risk for design error and complexity driven risk.



     I'm working an accident right now that happened

     for reasons involving a stirring of the recipe.

     An expensive, complex airplane carrying people

     hit the dirt for rudimentary lapses in judgement

     about electrical system architecture. There was

     always plenty of POWER available . . . but poorly

     conducted to critical components.



     I wish you well with your project. It's my

     best recommendation that you don't stack electrical

     uncertainties on top of the tasks before you.



     Bob . . .

flyboybob1(at)gmail.com
Guest

Posted: Sun Jan 24, 2010 8:41 am Post subject: Z-13/20 questions

Roger (ROGER &  JEAN CURTIS [mrspudandcompany(at)verizon.net]) wrote:



In taking a quick look at your diagram, it appears that your cross feed

contactor will not work.  You seem to have both sides of the contactor tied

together and through a switch (start/xfeed switch) to ground.  When you

power this up a diode will vaporize.



Roger, I don't think you saw the cross connect light between ground and the

cross connnect contactor positive. The cross connect light will limit

current and prevent the diodes from vaporizing (assuming light and diode

component values are sized appropriately).



Regards,

Bob Lee

N52BL  KR2

Suwanee, GA  USA

92% done only 67% to go!

mrspudandcompany(at)veriz
Guest

Posted: Sun Jan 24, 2010 10:11 am Post subject: Z-13/20 questions

Roger, I don't think you saw the cross connect light between ground and the

cross connnect contactor positive. The cross connect light will limit

current and prevent the diodes from vaporizing (assuming light and diode

component values are sized appropriately).



Regards,

Bob Lee

		Bob,



		My mistake, however, unless I am wrong again you will have

the cross feed actuated whenever the battery masters are turned on due to

the jumper between pins 1 & 3 of your Start/Xfeed switch.



		Roger

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Bob McC

Joined: 09 Jan 2006
Posts: 258
Location: Toronto, ON

Posted: Sun Jan 24, 2010 10:41 am Post subject: Z-13/20 questions

Hi Roger;  

Different Bob, but the starter/Xfeed switch depicted is a three position switch and with the switch in the “centre” position which is presumably intended to be the “normal” position the Xfeed is Off.  

Bob McC  

_____________________________________________

 From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)] On Behalf Of ROGER & JEAN CURTIS

 Sent: Sunday, January 24, 2010 1:08 PM

 To: aeroelectric-list(at)matronics.com

 Subject: RE: Re: Z-13/20 questions 

  

Roger, I don't think you saw the cross connect light between ground and the  

cross connnect contactor positive. The cross connect light will limit  

current and prevent the diodes from vaporizing (assuming light and diode  

component values are sized appropriately).  

Regards, 

  

Bob Lee 

  

Bob,  

My mistake, however, unless I am wrong again you will have the cross feed actuated whenever the battery masters are turned on due to the jumper between pins 1 & 3 of your Start/Xfeed switch.  

Roger 
    [quote][b]

_________________
Bob McC
Falco #908
(just starting)

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