Matronics Email Lists :: View topic - Z-14 v Z-14Fadec question

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Z-14 v Z-14Fadec question

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

CBarber(at)TexasAttorney.
Guest

Posted: Fri Jan 02, 2009 12:02 pm Post subject: Z-14 v Z-14Fadec question

Last week I asked about C/B's tripping in the NON  crossover mode and received a thoughtful answer.  Thanks.  Due to my  growing but limited knowledge in this area it took a EE buddy of mine to figure  out I had the crossover switch wired in a "mirrored" manner on my switch.   Now, no more C/B tripping AND my alternators are charging properly. So, my  initial calculations seemed to be ok as to wires etc....just not  my translation as to switch connections. Ahhhhhh, non-the-less, it now  feels nice.

  

 Now, I have a general question regarding the Z-14  schemes.  For the crossover switch, up is to engage the starter with both  batteries, center is non-crossover, normal mode with batteries working to power  their bus independently and down is both batteries working together on both  busses......If I understand correctly.  So, in the Z-14 Fadec scheme, the  start button engages the starter, then one position on the switch is independent  alt to each bus and the other switch to have the systems work together? Or, is  on position Off and the other switch position engaging both alternators to work  together?  If it is the second scenario, does that mean the two systems  ALWAYS work together?  If so, is there any reason not to have both systems  always working together in the standard Z-14 scheme.  I assume the FADEC  label is since it is always engaged there is no pilot intervention.  Just  looking for a better understanding.  Thanks.

  

 All the best,

  

 Chris Barber

 Houston

 Velocity SE with all electric Mazda 13b  rotary

    [quote][b]

- 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

klehman(at)albedo.net
Guest

Posted: Fri Jan 02, 2009 6:26 pm Post subject: Z-14 v Z-14Fadec question

Chris

On my Z14 I have a two position crossfeed switch. In the normal OFF 

position the two systems run isolated from each other. That way a fault 

in one system can't affect the other. In the ON position the crossfeed 

contactor closes and parallels the batteries. I would only do that if 

one alternator went dead and I wished to continue flying for sometime or 

to get to a repair facility.  In addition since I run very small 

batteries on my system, the crossfeed contactor is wired to close 

automatically any time I crank the engine to start it.

Ken

ej22 and dual EFI



Christopher Barber wrote:

 	  Quote: 	
		   Last week I asked about C/B's tripping in the NON crossover mode and 

 received a thoughtful answer.  Thanks.  Due to my growing but limited 

 knowledge in this area it took a EE buddy of mine to figure out I had 

 the crossover switch wired in a "mirrored" manner on my switch.  Now, no 

 more C/B tripping AND my alternators are charging properly. So, my 

 initial calculations seemed to be ok as to wires etc....just not 

 my translation as to switch connections. Ahhhhhh, non-the-less, it now 

 feels nice.

  

 Now, I have a general question regarding the Z-14 schemes.  For the 

 crossover switch, up is to engage the starter with both batteries, 

 center is non-crossover, normal mode with batteries working to power 

 their bus independently and down is both batteries working together on 

 both busses......If I understand correctly.  So, in the Z-14 Fadec 

 scheme, the start button engages the starter, then one position on the 

 switch is independent alt to each bus and the other switch to have the 

 systems work together? Or, is on position Off and the other switch 

 position engaging both alternators to work together?  If it is the 

 second scenario, does that mean the two systems ALWAYS work together?  

 If so, is there any reason not to have both systems always working 

 together in the standard Z-14 scheme.  I assume the FADEC label is since 

 it is always engaged there is no pilot intervention.  Just looking for a 

 better understanding.  Thanks.

  

 All the best,

  

 Chris Barber

 Houston

 Velocity SE with all electric Mazda 13b rotary

- 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

nuckolls.bob(at)aeroelect
Guest

Posted: Sat Jan 03, 2009 11:12 am Post subject: Z-14 v Z-14Fadec question

 	  Quote: 	
		  

 Now, I have a general question regarding the Z-14 schemes.  For the crossover switch, up is to engage the starter with both batteries, center is non-crossover, normal mode with batteries working to power their bus independently and down is both batteries working together on both busses......If I understand correctly.  So, in the Z-14 Fadec scheme, the start button engages the starter, then one position on the switch is independent alt to each bus and the other switch to have the systems work together? Or, is on position Off and the other switch position engaging both alternators to work together?  If it is the second scenario, does that mean the two systems ALWAYS work together?  If so, is there any reason not to have both systems always working together in the standard Z-14 scheme.  I assume the FADEC label is since it is always engaged there is no pilot intervention.  Just looking for a better understanding.  Thanks. 	




  Two ideas drove the crafting the first iteration of of Z-14

  many moons ago.



  (1) For operators that plan a highly

   redundant electrical and instrumentation system

   for flight in marginal to adverse conditions,

   two independent systems is desirable/

   practical by teaming a conventional main alternator

   with a vacuum pump pad driven alternator.



  (2) Both systems need their own battery. With fully

   redundant systems having cross-feed capability, one

   may strive for smallest practical batteries with the

   notion that battery-only flight is exceedingly 

   improbable. However, small batteries don't crank

   engines well . . . so auto-crossfeed or paralleling

   small batteries during engine cranking is a useful

   thing to consider.



   The two systems are never cross-connected for normal

   operations. Each system receives the benefit of

   a load analysis. Pairs of redundant electronics

   are distributed between the two systems.



   Some years later we were offered electro-whizzies

   with desirable performance characteristics

   under normal operating conditions but not designed

   to live in the real-world of vehicular DC power systems.



   During starter motor inrush time, system voltage can

   sag sufficiently low, sufficiently long . .  .



  http://tinyurl.com/6tbry6 



   that some appliances wander off into the weeds or

   take an untimely interval to reboot.



   These appliances include but are not limited to

   electronic ignitions, electronic fuel injection,

   EFIS systems, FADECs, etc.



   This prompted the addition of two Band-Aids to

   the Z-figures. The FADEC version of Z-14 suggested

   elimination of the auto-crossfeed feature during

   cranking. 



   Another version of Z-13/8 was crafted to add

   a brownout protection battery and auto-disconnect

   relay to support e-bus loads during engine-cranking



  http://tinyurl.com/7q2usj 

   

   The supposition you offered at the end of your post

   is not correct. The cross-feed switch in the FADEC

   version of Z-14 is never closed except to allow

   ONE working alternator to support both sides of the

   system (within that alternator's limitations). The

   switch is left open all other times. Recalcitrant

   systems are operated from the Aux Battery which is

   NOT loaded during engine cranking.



 

        Bob . . .



        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------



     [quote][b]

- 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

Display posts from previous:

	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