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Z13/8 all electric airplane

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maurv8(at)gmail.com
Guest

Posted: Thu May 16, 2013 4:39 pm Post subject: Z13/8 all electric airplane

Bob,

 I'm using your Z-13/8  diagram wiring my RV-8 and want to use a CB Switch combo to replace the  individual circuit breaker and switch for the AUX ALT ON/OFF SWITCH.  The  circuit breaker has two terminals labeled line & load. Which one do I hook  to GND?

  

 Mauri  Morin

   [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Fri May 17, 2013 9:08 am Post subject: Z13/8 all electric airplane

At 07:38 PM 5/16/2013, you wrote:

  	  Quote: 	
		   Bob,

 I'm using your Z-13/8 diagram wiring my RV-8 and want to use a CB Switch combo to replace the individual circuit breaker and switch for the AUX ALT ON/OFF SWITCH.  The circuit breaker has two terminals labeled line & load. Which one do I hook to GND?

  	


  Either one.



 

 

   Bob . . .    [quote][b]

jonlaury

Joined: 06 Nov 2006
Posts: 336

Posted: Sat May 18, 2013 12:39 pm Post subject: Re: Z13/8 all electric airplane

(at) Bob: "Either one" really?



I may be missing something here, but wouldn't " Line" indicate the battery and "load" would indicate the Aux Alt field. 



If "Line" is Batt Positve, connecting "Load" to ground  will trip the breaker.

nuckolls.bob(at)aeroelect
Guest

Posted: Sat May 18, 2013 3:06 pm Post subject: Z13/8 all electric airplane

At 03:39 PM 5/18/2013, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "jonlaury" <jonlaury(at)impulse.net>



 (at) Bob: "Either one" really?



 I may be missing something here, but wouldn't " Line" indicate the battery and "load" would indicate the Aux Alt field. 



 If "Line" is Batt Positve, connecting "Load" to ground  will trip the breaker.



 

 	


   yep, here's a thread from 2008



 Quote:

 I am rewiring my Navion panel using busses with Potter-Brumfield W31 

 switch breakers and Klixon 7277 c/b's. I put the P-B buss bar on the 

 bottom following their Load-Line labeling but put the Klixon bar on top to 

 ease access to the load terminals. My IA neighbor (not my supervising IA) 

 tried to tell me it was backward but I had already checked and there is no 

 labeling on the Klixon c/b's. I see no intuitive reason it should care 

 about polarity but then I don't have a real understanding of their inner 

 workings. Did I miss something? Does polarity matter for the Klixons? If 

 so, I can change my buss. If not, why does P-B label their units (it's 

 also on their W23 c/b's?) Is it real or just a case of eliminating choice? 

 Thanks for the education. 



 BN: Intuitively, the physics of a series-connected 

 heat-tripped, switch do not suggest a reason why 

 the breaker would care which way electrons flow 

 through it . . . and in particular, AC system 

 breakers where electrons are known to turn around 

 and run the other direction 120 times a second! 



 You've already had some good responses but I'll 

 take this opportunity to elaborate. Not all 

 breakers are rudimentary . . . i.e. a simple 

 spring-loaded, heater-tripped latch holding a 

 set of single or double-break contacts closed. 



 Breakers can be had with auxiliary switches, 

 indicator lights, voltage sense coils, and 

 all manner of enhancements where proper function 

 of the enhancement depends on a connection to 

 power being available even when the breaker is 

 open. Obviously, some third terminal is necessary 

 for an enhancement to function, this is sometimes 

 an obvious connection, or perhaps it gets hooked 

 up through the mounting. 



 In any case, it's not uncommon for a manufacturer 

 to use common tooling to mold a breaker housing 

 for all versions, hence you often see the word 

 "load", "line" or both formed right next to the 

 breaker's terminals . . . 



 I've asked several tech reps for breakers and 

 except for enhanced breakers, orientation in 

 the system doesn't matter. Interestingly enough, 

 if an electrician encounters "line" and/or "load" 

 labels on a breaker, he'll wire it up that way 

 whether it matters or not. And I suspect many 

 aviation techs do too . . . not because the 

 physics matters but because some inspector who 

 doesn't know any better can be counted on to 

 insist that the protocols be followed. 



 The only time I've encountered this as a 

 "problem" is when a builder finds it convenient 

 to fabricate a two-row bus-bar and take load 

 feeders off opposite ends of the breaker. When 

 they come stamped with a breaker rating, 

 they look pretty funky with one row upside-down 

 in their holes! 



 

   Bob . . .    [quote][b]

jonlaury

Joined: 06 Nov 2006
Posts: 336

Posted: Sun May 19, 2013 7:18 am Post subject: Re: Z13/8 all electric airplane

[/quote]

   yep, here's a thread from 2008...

 

   Bob . . .   [quote]



Bob,

My question was less about electron directional flow than it was about the fellow's intention to connect the switch/breaker to GND. Unless he is switching/breaking the GND to control the alternator field, which I thought in most instances was bad practice, isn't he wiring up a dead short that will trip the breaker everytime the alt field is switched on?

Bob McC

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

Posted: Sun May 19, 2013 9:05 am Post subject: Z13/8 all electric airplane

Jon;



Did you look at  schematic Z13/8 to see what is being discussed?? There is

no "field" associated with the AUX alternator as it's a PM type. (Dynamo in

the dwg) The schematic clearly shows the breaker and switch connected

between the alternator "B" lead relay and ground. And yes, when the over

voltage module operates it causes a direct short to ground through this

breaker tripping it.



Bob McC



[quote] --

_________________
Bob McC
Falco #908
(just starting)

nuckolls.bob(at)aeroelect
Guest

Posted: Sun May 19, 2013 10:38 am Post subject: Z13/8 all electric airplane

 	  Quote: 	
		  My question was less about electron directional flow than it was 

about the fellow's intention to connect the switch/breaker to GND. 

Unless he is switching/breaking the GND to control the alternator 

field, which I thought in most instances was bad practice, isn't he 

wiring up a dead short that will trip the breaker everytime the alt 

field is switched on?


	


   As Bob suggests . . . trace the circuit.

   The alternator control switch is used to

   energize a relay that connects the PM

   alternator to the BUS.



   The control relay coil is paralleled with

   a crowbar OVM . . . open circuit 99.99%

   of the time but becomes a dead short

   when voltage across the device exceeds

   about 16.4 volts.



   The "short" across the relay coil would

   indeed force it to relax the contacts and

   disconnect the offending alternator from

   the bus. But it would also burn the wires

   that supply power to the relay coil through

   the closed switch.



   The goal for keeping one's cockpit smoke free

   suggest some form of fault current mitigation

   like a fuse, breaker, polyswitch, etc.

   In this case it's a breaker which can be ANYWHERE

   along the series path from bus to ground.



   Actually, I've been contemplating replacement of

   the breaker in that drawing with a polyswitch.

   Given the low current demands for driving the

   relay coil, this would be an excellent place

   to incorporate a polyswitch. I'm wrestling

   with annunciation issues.  A popped breaker is,

   not a great annunciator but it's not bad. If

   we 'hide' a tripped condition by going solid

   state polyfuse, then perhaps some form of OV

   TRIP indication is called for.



   I've got some ideas and will incorporate the

   most elegant configuration into the Z-figures

   that control PM alternators with the RELAY/OVM

   combination.



   Bob . . .

jonlaury

Joined: 06 Nov 2006
Posts: 336

Posted: Mon May 20, 2013 9:09 am Post subject: Re: Z13/8 all electric airplane

[quote="Bob McC"]Jon;



Did you look at  schematic Z13/8 to see what is being discussed?? There is

no "field" associated with the AUX alternator as it's a PM type. ..



Bob McC



 	  Quote: 	
		   -- 	




Both Bobs,

There's the disconnect 

I parachuted into this thread with a bias toward a non-PM alternator backup because that's what mine is and I'd used 13/8 as a foundation for my system.



Sorry for the confusion.



John

eschlanser

Joined: 08 Apr 2010
Posts: 60

Posted: Thu May 23, 2013 8:37 am Post subject: Re: Z13/8 all electric airplane

Bob,



 Instead of a polyswitch in the PM alternator circuit, may I suggest using the Linear OVP module from PerhelionDesign.com? http://www.periheliondesign.com/lovm.htm



 Disclaimer: I have no connection with the company except for using the LOVP instead of crowbar OVM/RELAY combinations in both main alternator (IR) and aux alternator (SD8) circuits in my project's Z-13-8 derived electrical system.

 I had considered using polyswitchs. True, the LOVP module is way more expensive than polyswitches. But in return for the cost, the engineering work has been done. It has provision for an Led lite annunciator and a reset feature. I don't understand all the engineering, but it seems to me that a thermally activated polyswitch is not under the pilot's control. After cooling, wouldn't it keep trying to reset itself?

 I'd like to see how you would use the Perhelion LOVP in Z13/8 as I struggled with the wiring.



Eric S.

Z13/8 in a W-10 Tailwind/O-320 project



[/quote]

   Actually, I've been contemplating replacement of

   the breaker in that drawing with a polyswitch.

   Given the low current demands for driving the

   relay coil, this would be an excellent place

   to incorporate a polyswitch. I'm wrestling

   with annunciation issues.  A popped breaker is,

   not a great annunciator but it's not bad. If

   we 'hide' a tripped condition by going solid

   state polyfuse, then perhaps some form of OV

   TRIP indication is called for.



   I've got some ideas and will incorporate the

   most elegant configuration into the Z-figures

   that control PM alternators with the RELAY/OVM

   combination.



   Bob . . .[/quote]

nuckolls.bob(at)aeroelect
Guest

Posted: Thu May 23, 2013 10:19 am Post subject: Z13/8 all electric airplane

At 11:37 AM 5/23/2013, you wrote:

 	  Quote: 	
		  



Bob,



  Instead of a polyswitch in the PM alternator circuit, may I 

 suggest using the Linear OVP module from PerhelionDesign.com? 

 http://www.periheliondesign.com/lovm.htm


	


   That is one of many ov management options

   used in vehicular DC power systems . . .



 	  Quote: 	
		    I had considered using polyswitchs. True, the LOVP module is way 

 more expensive than polyswitches. But in return for the cost, the 

 engineering work has been done. It has provision for an Led lite 

 annunciator and a reset feature. I don't understand all the 

 engineering, but it seems to me that a thermally activated 

 polyswitch is not under the pilot's control. After cooling, 

 wouldn't it keep trying to reset itself?


	


   The polyswitch does not go open, only to a high

   resistance state which keeps drawing enough current

   to STAY in that high resistance state. This means

   that fault current that would put wiring at risk is

   limited to some acceptably low value. In the

   case OV management for the PM alternator, the

   NORMAL current that holds the relay closed will

   not drip the polyswitch. A dead short OV module

   connected across the relay would burn wires unless

   a fuse, breaker or polyswitch did not respond to

   limit the current. Fuses and breakers take the current

   to zero . . . the polyswitch takes it to some low,

   non-hazardous value. Either philosophy is consistent

   with Z-13/8 design goals.



   In the interim, I've once again backed off the incorporation

   of the polyswitch. NOT because it fails to function

   as advertised but because it's designed to mount to

   an ECB. Artful incorporation of the polyswitch into

   Z-13/8 PM alternator control calls for mounting it

   into some fabricated assembly. I looked at a surface

   mounted device on an ECB along with resistors to

   drive a 'tripped' indicator light.



   Too much monkey motion . . . so my track record is

   still intact. Since my first introduction to the

   realm of inrush limiters and polyfuses at LearJet

   in 1980, I've not discovered an elegant way to

   incorporate these critters into airframe system

   wiring. They work fine as a component INTERNAL to

   a black box.

 	  Quote: 	
		    I'd like to see how you would use the Perhelion LOVP in Z13/8 as I 

 struggled with the wiring.


	


   You use it per the installation instructions. It's

   wired in series with the device that you want to

   shut down in the event of an ov condition.



   The point of Z13/8 is to mitigate "struggling". The

   drawing is not intended to be the epitome of systems

   but simply an elegant solution that meets design goals

   for the system.



   There are certainly useful variations on the theme

   that can and should be considered if the drawing

   as-presented fails to meet some other design goal.



   Assuming you perceive a need to depart from the

   suggested wiring, what new or overlooked design goal

   needs attention? In other words, what feature of Z-13/8

   drives your willingness/need to "struggle"? What

   changes are you considering and what is the anticipated

   return on investment for the change?



   Bob . . .

eschlanser

Joined: 08 Apr 2010
Posts: 60

Posted: Thu May 23, 2013 3:01 pm Post subject: Re: Z13/8 all electric airplane

Bob,



 Thank you for the education on the polyswitch. Once again, you cleared up an electrical design for me.



 Z13/8 is awesome. The only reason I changed anything in Z13/8 was due to the advertising for the LOVP. The marketing sold me on it. However, the LOVP has more wires and connections than the crowbar OV, making it more involved to incorporate. 



 For this first timer, anything electrical is a struggle. I should have built the absolute simplest system,  Z11, first. Then, I could have worked my way up to Z13/8 after getting some practical experience in the art. 

 Attending one of your seminars and studying the AEC have been great exposure to the formal discipline of aircraft electrical science. 



Thanks again for so generously sharing your experience, 



Eric S.

 

[/quote]

   Assuming you perceive a need to depart from the

   suggested wiring, what new or overlooked design goal

   needs attention? In other words, what feature of Z-13/8

   drives your willingness/need to "struggle"? What

   changes are you considering and what is the anticipated

   return on investment for the change?



   Bob . . .[/quote]

nuckolls.bob(at)aeroelect
Guest

Posted: Thu May 23, 2013 4:42 pm Post subject: Z13/8 all electric airplane

At 06:01 PM 5/23/2013, you wrote:

 	  Quote: 	
		  



Bob,



  Thank you for the education on the polyswitch. Once again, you 

 cleared up an electrical design for me.



  Z13/8 is awesome. The only reason I changed anything in Z13/8 was 

 due to the advertising for the LOVP. The marketing sold me on it. 

 However, the LOVP has more wires and connections than the crowbar 

 OV, making it more involved to incorporate.



  For this first timer, anything electrical is a struggle. I should 

 have built the absolute simplest system,  Z11, first. Then, I could 

 have worked my way up to Z13/8 after getting some practical 

 experience in the art.

  Attending one of your seminars and studying the AEC have been 

 great exposure to the formal discipline of aircraft electrical science.



Thanks again for so generously sharing your experience,


	


   You're most welcome . . . it's what we do. Without

   a doubt, the LVOP performs as advertised. My best

   counsel is to set system desing goals and then

   work for lowest parts count, weight and cost of

   ownership.



   I fiddled with a little different technique for

   incorporating the Polyswitch into the PM alternator

   OV protection . . . even came up with a little ECB

   to carry a surface mount device along with the companion

   resistors for trip annunciation. It would have been a

   new product to offer . . .



   Problem was that it applied to a limited number

   of total situations for replacing a CB . . . namely

   the disconnect relay for a PM alternator.



   The 9024 4-function module is slated to replace crowbar

   ovm in the control of PM alternators. So to spend $resources$

   to spruce up a low-volume application slated to be obsolete

   just didn't make sense.



   Getting on the List and standing your own design goals

   against recipes for success is the very best way to

   strive for the elegant solution. It's a collegial service

   I enjoyed during my tenures at Electro-Mech and Beech.

   No reason it shouldn't work here too.



   Bob . . .



   Bob . . .

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