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dan(at)azshowersolutions.
Guest

Posted: Tue Dec 27, 2011 1:41 am Post subject: First Engine Start Problem

Bob,

I have had the Kitfox wiring completed for about 8 months now and I used the new Z-16 schematic. I have most of my avionics on the E-Bus and they have been working well since day one when I first flipped the switch. A week ago the day came to do my first engine start. As it goes with the Rotax 912uls, we purged the oil system then began turning the prop looking for oil pressure. After turning it through several times by hand we decided to then let the starter do the work. The starter turned the engine over well, however, I was dismayed when my whole panel of avionics went dead. I of course quit cranking and began troubleshooting. It didn't take long to find that the fuseable link off the Batt Contactor (heading to the E-Bus) burned through. I went ahead and bypassed the link with 16 AWG and was able to  complete a successful first engine start. The guys that were working with me asked me why that link was there...I did not have a good answer for them. I do have the diode in place, yet I assume a "spike" occurred when I turned the engine over. So...I am now reluctant to put another fuseable link in place but have a concern if there is still a problem that burned my link in the first place. 

I am open to comments and suggestions. 

Thanks,

Dan Billingsley

Mesa, AZ



 [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Dec 27, 2011 4:17 am Post subject: First Engine Start Problem

At 03:37 AM 12/27/2011, you wrote:

 	  Quote: 	
		  Bob,

I have had the Kitfox wiring completed for about 8 months now and I 

used the new Z-16 schematic. I have most of my avionics on the E-Bus 

and they have been working well since day one when I first flipped the switch.


	


   What is the total list of goodies on the e-bus?

 	  Quote: 	
		    A week ago the day came to do my first engine start. As it goes 

 with the Rotax 912uls, we purged the oil system then began turning 

 the prop looking for oil pressure. After turning it through several 

 times by hand we decided to then let the starter do the work. The 

 starter turned the engine over well, however, I was dismayed when 

 my whole panel of avionics went dead. I of course quit cranking and 

 began troubleshooting. It didn't take long to find that the 

 fuseable link off the Batt Contactor (heading to the E-Bus) burned 

 through. I went ahead and bypassed the link with 16 AWG and was 

 able to complete a successful first engine start. The guys that 

 were working with me asked me why that link was there...I did not 

 have a good answer for them. I do have the diode in place, yet I 

 assume a "spike" occurred when I turned the engine over. So...I am 

 now reluctant to put another fuseable link in place but have a 

 concern if there is still a problem that burned my link in the first place.

I am open to comments and suggestions.


	


    Any and all sorts of fault protection (links,

    fuses, breakers, etc) are there to protect wires.

    The idea of an e-bus is to power up electro-whizzies

    most useful for ALTERNATOR OUT EN ROUTE ENDURANCE

    while operating battery only. This alternate feed

    path goes around the battery contactor thus offering

    an opportunity to (1) eliminate battery contactor loads

    on the battery or (2) get a minimum list of useful goodies

    powered if the contactor or its control circuit fails.



    You didn't have a 'spike' . . . you had some level

    of LOAD that was greater than what the 22AWG link

    would carry. Having a list of goodies powered from the

    e-bus will give us the first clues as to why such

    a load existed.

   Bob . . .

mrspudandcompany(at)veriz
Guest

Posted: Tue Dec 27, 2011 6:14 am Post subject: First Engine Start Problem

You didn't have a 'spike' . . . you had some level

    of LOAD that was greater than what the 22AWG link

    would carry. Having a list of goodies powered from the

    e-bus will give us the first clues as to why such

    a load existed.

   Bob . . . 

		Since this is a new wiring installation, you may want to

check your wiring again.  Especially look to make sure that you do not

somehow have starter current through your fusible link.



		Roger

winmail.dat

Description:

Download

Filename:

winmail.dat

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Downloaded:

474 Time(s)

dan(at)azshowersolutions.
Guest

Posted: Tue Dec 27, 2011 6:51 am Post subject: First Engine Start Problem

Thanks for the quick reply. I will be going to the airport today and take inventory of the e-bus goodies. I understand and accept that this could be an over-Load problem so I may need to transfer a couple things to the main bus. What troubles me is I have had this E-bus circuit working many times with everything turned on sometimes for 5 to 10 minutes without a hitch. Will start with a current tally and get back.

Dan



[quote]       From: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com>

 To: aeroelectric-list(at)matronics.com 

 Sent: Tuesday, December 27, 2011 5:14 AM

 Subject: Re: AeroElectric-List: First Engine Start Problem

  

 --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>



At 03:37 AM 12/27/2011, you wrote:

 	  Quote: 	
		   Bob,

 I have had the Kitfox wiring completed for about 8 months now and I used the new Z-16 schematic. I have most of my avionics on the E-Bus and they have been working well since day one when I first flipped the switch.


	


  What is the total list of goodies on the e-bus?

 	  Quote: 	
		    A week ago the day came to do my first engine start. As it goes with the Rotax 912uls, we purged the oil system then began turning the prop looking for oil pressure. After turning it through several times by hand we decided to then let the starter do the work. The starter turned the engine over well, however, I was dismayed when my whole panel of avionics went dead. I of course quit cranking and  began troubleshooting. It didn't take long to find that the fuseable link off the Batt Contactor (heading to the E-Bus) burned through. I went ahead and bypassed the link with 16 AWG and was able to complete a successful first engine start. The guys that were working with me asked me why that link was there...I did not have a good answer for them. I do have the diode in place, yet I assume a "spike" occurred when I turned the engine over. So...I am now reluctant to put another fuseable link in place but have a concern if there is still a problem that burned my link in the first place.

 I am open to comments and suggestions.


	


   Any and all sorts of fault protection (links,

   fuses, breakers, etc) are there to protect wires.

   The idea of an e-bus is to power up electro-whizzies

   most useful for ALTERNATOR OUT EN ROUTE ENDURANCE

   while operating battery only. This alternate feed

   path goes  around the battery contactor thus offering

   an opportunity to (1) eliminate battery contactor loads

   on the battery or (2) get a minimum list of useful goodies

   powered if the contactor or its control circuit fails.



   You didn't have a 'spike' . . . you had some level

   of LOAD that was greater than what the 22AWG link

   would carry. Having a list of goodies powered from the

   e-bus will give us the first clues as to why such

   a load existe========================www.builders                    -Matt          - The AeroElectric-List Email Forum -http://www.matronics.com/Navigator?Aersp;              - MATRONICS WEB FORUMS -

sp;  --> http://ww=======================



 

 

 [b]

tperry(at)lvtofly.com
Guest

Posted: Tue Dec 27, 2011 7:19 am Post subject: First Engine Start Problem

Sound like you have a loose connection. When you cranked the engine something that was not touching now was.  There is often a lot of movement with the engine start you don't get with it just sitting there.  And during your troubleshooting you might have moved the offending conbection where it no longer is making contact.  I have had this type of problem before and it really sucks when it happens during flight, but best to have a good breaker or fuse blow than a fire....

Tim



Sent from my iPhone



On Dec 27, 2011, at 9:46 AM, Dan Billingsley <dan(at)azshowersolutions.com (dan(at)azshowersolutions.com)> wrote:



[quote]Thanks for the quick reply. I will be going to the airport today and take inventory of the e-bus goodies. I understand and accept that this could be an over-Load problem so I may need to transfer a couple things to the main bus. What troubles me is I have had this E-bus circuit working many times with everything turned on sometimes for 5 to 10 minutes without a hitch. Will start with a current tally and get back.

Dan



 	  Quote: 	
		         From: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>

 To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com) 

 Sent: Tuesday, December 27, 2011 5:14 AM

 Subject: Re: First Engine Start Problem

  

 --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>



At 03:37 AM 12/27/2011, you wrote:

 	  Quote: 	
		   Bob,

 I have had the Kitfox wiring completed for about 8 months now and I used the new Z-16 schematic. I have most of my avionics on the E-Bus and they have been working well since day one when I first flipped the switch.


	


  What is the total list of goodies on the e-bus?

 	  Quote: 	
		    A week ago the day came to do my first engine start. As it goes with the Rotax 912uls, we purged the oil system then began turning the prop looking for oil pressure. After turning it through several times by hand we decided to then let the starter do the work. The starter turned the engine over well, however, I was dismayed when my whole panel of avionics went dead. I of course quit cranking and  began troubleshooting. It didn't take long to find that the fuseable link off the Batt Contactor (heading to the E-Bus) burned through. I went ahead and bypassed the link with 16 AWG and was able to complete a successful first engine start. The guys that were working with me asked me why that link was there...I did not have a good answer for them. I do have the diode in place, yet I assume a "spike" occurred when I turned the engine over. So...I am now reluctant to put another fuseable link in place but have a concern if there is still a problem that burned my link in the first place.

 I am open to comments and suggestions.


	


   Any and all sorts of fault protection (links,

   fuses, breakers, etc) are there to protect wires.

   The idea of an e-bus is to power up electro-whizzies

   most useful for ALTERNATOR OUT EN ROUTE ENDURANCE

   while operating battery only. This alternate feed

   path goes  around the battery contactor thus offering

   an opportunity to (1) eliminate battery contactor loads

   on the battery or (2) get a minimum list of useful goodies

   powered if the contactor or its control circuit fails.



   You didn't have a 'spike' . . . you had some level

   of LOAD that was greater than what the 22AWG link

   would carry. Having a list of goodies powered from the

   e-bus will give us the first clues as to why such

   a load existe========================www.builders                    -Matt          - The AeroElectric-List Email Forum -http://www.matronics.com/Navigator?Aersp;              - MATRONICS WEB FORUMS -

sp;  --> http://ww=======================



 

 

 	


   

  	  Quote: 	
		  



===================================

" face="courier new,courier">www.aeroelectric.com

 	  Quote: 	
		  www.buildersbooks.com

uilthelp.com
	


matronics.com/contribution

===================================

st">http://www.matronics.com/Navigator?AeroElectric-List

===================================

cs.com

===================================

matronics.com/contribution

===================================



	


[b]

zodiac601

Joined: 11 Jul 2011
Posts: 7

Posted: Tue Dec 27, 2011 7:35 am Post subject: Re: First Engine Start Problem

My guess is an overloaded e bus. When you cranked, the voltage dropped and the amps of everything went up. watts = volts x amps. 



If the battery voltage dropped 20% during cranking, then the amperage of everything went up 20% as well.

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Dec 27, 2011 10:26 am Post subject: First Engine Start Problem

At 09:35 AM 12/27/2011, you wrote:

 	  Quote: 	
		  



My guess is an overloaded e bus. When you cranked, the voltage 

dropped and the amps of everything went up. watts = volts x amps.



If the battery voltage dropped 20% during cranking, then the 

amperage of everything went up 20% as well.


	


    For the vast majority of electro-whizzies, current

    draw does not go up and input voltage goes down. Modern

    avionics with switchmode power supplies are 'constant

    power' systems but even then, the increase is not THAT

    profound for the duration of a cranking cycle. It takes

    a LOT more current to fuse a 22AWG wire than you might

    suppose. See:



http://aeroelectric.com/Pictures/Wire/22AWG_20A.pdf



    Current ratings for wire is bounded by INSULATION

    performance, not COPPER performance. If he fused

    a 22AWG link, something rather profound occurred.

   Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Dec 27, 2011 10:29 am Post subject: First Engine Start Problem

At 08:46 AM 12/27/2011, you wrote:

  	  Quote: 	
		  Thanks for the quick reply. I will be going to the airport today and take inventory of the e-bus goodies. I understand and accept that this could be an over-Load problem so I may need to transfer a couple things to the main bus. What troubles me is I have had this E-bus circuit working many times with everything turned on sometimes for 5 to 10 minutes without a hitch. Will start with a current tally and get back. 	


  In particular, do you have any loads that are not

  generally described in the suggested list of

  endurance goodies I've written about? Is your

  starter system dependent upon e-bus supply of

  energy in any way?



 

 

   Bob . . .    [quote][b]

dan(at)azshowersolutions.
Guest

Posted: Tue Dec 27, 2011 5:44 pm Post subject: First Engine Start Problem

From: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com>

To: aeroelectric-list(at)matronics.com

Sent: Tue, December 27, 2011 11:27:05 AM

Subject: Re: First Engine Start Problem

   At 08:46 AM 12/27/2011, you wrote:

  	  Quote: 	
		  Thanks for the quick reply. I will be going to the airport today and take inventory of the e-bus goodies. I understand and accept that this could be an over-Load problem so I may need to transfer a couple things to the main bus. What troubles me is I have had this E-bus circuit working many times with everything turned on sometimes for 5 to 10 minutes without a hitch. Will start with a current tally and get back. 	

  In particular, do you have any loads that are not

  generally described in the suggested list of

  endurance goodies I've written about? Is your

  starter system dependent upon e-bus supply of

  energy in any way?

No, the starter system is drawn off the main buss. I was not able to take a tally on the goodies today but it is in the cards for tomorrow. I will get back the info to the list as soon as I round it up. I will say that there are quite a few things on the E-Bus as compared to the Main. Doing a tally on the amps drawn when all is on at the E-Bus is something I neglected to do, so I am quite interested in figuring it out. Thanks all for the comments and suggestions.

Dan

    Bob . . .     	  Quote: 	

 [quote][b]

aerobubba(at)earthlink.ne
Guest

Posted: Wed Dec 28, 2011 1:11 am Post subject: First Engine Start Problem

Howdy-



Re:

 we decided to 

 	  Quote: 	
		  then let the starter do the work. The starter turned the engine over well, 

however, I was dismayed when my whole panel of avionics went dead. I of cou

rse quit cranking and began troubleshooting. It didn't take long to find th

at the fuseable link off the Batt Contactor (heading to the E-Bus) burned t

hrough. I went ahead and bypassed the link with 16 AWG and was able to comp

lete a successful first engine start. 


	


I'm on the road at the moment (beautiful dowtown Bahrain...) and don't have the relevant docs with me, but if Z-16 has the E bus fed through a diode down stream from the battery contactor and / or through the E bus switch from upstream of the battery contactor, and the diode were installed reverse biased.....



Without other explicit details, this and the idea about engine flail bringing a grounded chunk of hardware into physical contact with an energized bit of the E bus architecture are all I can think of.



Glen Matejcek

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Dec 28, 2011 6:07 am Post subject: First Engine Start Problem

I'm on the road at the moment (beautiful dowtown Bahrain...) and 

don't have the relevant docs with me, but if Z-16 has the E bus fed 

through a diode down stream from the battery contactor and / or 

through the E bus switch from upstream of the battery contactor, and 

the diode were installed reverse biased.....



   Good call Glen. I did not pick up on the

   fact that the fusible link in question was

   in series with the ALTERNATE feed switch . . .

   which should be OPEN for all but pre-flight

   tests -OR- in-flight, alternator-out operations.



   Combine this closed switch with a reversed

   NORMAL feed path diode could account for the

   severe overload of the link.



   Dan, do your e-bus feed accessories work with

   the alternate feed switch OFF? If not, check

   the normal feed path diode for proper polarity.



   Bob . . .

dan(at)azshowersolutions.
Guest

Posted: Wed Dec 28, 2011 6:39 am Post subject: First Engine Start Problem

[quote]       From: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com>

 To: aeroelectric-list(at)matronics.com 

 Sent: Wednesday, December 28, 2011 7:03 AM

 Subject: Re: AeroElectric-List: Re: First Engine Start Problem

 --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>

I'm on the road at the moment (beautiful dowtown Bahrain...) and don't have the relevant docs with me, but if Z-16 has the E bus fed through a diode down stream from the battery contactor and / or through the E bus switch from upstream of the battery contactor, and the diode were installed reverse biased.....

  Good call Glen. I did not pick up on the

  fact that the fusible link in question was

  in series with the ALTERNATE feed switch . . .

  which should be OPEN for all but pre-flight

  tests -OR- in-flight, alternator-out operations.

  Combine this closed switch with a reversed

  NORMAL feed path diode could account for the

  severe overload of the  link.

  Dan, do your e-bus feed accessories work with

  the alternate feed switch OFF? If not, check

  the normal feed path diode for proper polarity.

No, the E-Bus switch must be ON in order for any of the accessories to operate. I will take another look at the diode polarity as well. One of the guys I am working with suggested I not turn on the E-Bus switch until After I start the engine. That could become a practice, yet it does go against the grain of how things "should" work. Will get back with the info soon. 

www.aeroelectric.com</;    * HomebuiltHELP http://www.matronics.com/Navigator?AeroElectution Web Site ;                     &nb="http://www.matronics.com/contribution" target="_blank">http://www.mat=====================

 [b]

user9253

Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan

Posted: Wed Dec 28, 2011 7:25 am Post subject: Re: First Engine Start Problem

 	  Quote: 	
		  No, the E-Bus switch must be ON in order for any of the accessories to operate. I will take another look at the diode polarity as well. One of the guys I am working with suggested I not turn on the E-Bus switch until After I start the engine. 	


The E-Bus should be energized with the E-Bus switch off and the master switch on.  If not, the diode is backwards.

  Although it will not hurt anything to fly with the E-Bus switch turned on, it is intended to be turned on only in the event that power is not available through the diode.

Joe

_________________
Joe Gores

dan(at)azshowersolutions.
Guest

Posted: Wed Dec 28, 2011 5:43 pm Post subject: First Engine Start Problem

Bob and Joe, thank you for pointing out both over loading ( I went back and read note 12) and the fact that the E-bus should be working with the Alternate switch off. To tell the truth, I have not tried it that way (w/just the Master on). If it does not work I do see that would mean the diode between the two buses is in backwards. I did check the diode position on the Batt Contactor and it IS installed the right way. I now have at the very least, some changing of circuits over to the Main bus. Will report back on findings after tomorrow. 

Dan



[quote]       From: user9253 <fran4sew(at)banyanol.com>

 To: aeroelectric-list(at)matronics.com 

 Sent: Wednesday, December 28, 2011 8:25 AM

 Subject: AeroElectric-List: Re: First Engine Start Problem

  

 --> AeroElectric-List message posted by: "user9253" <fran4sew(at)banyanol.com (fran4sew(at)banyanol.com)>

 	  Quote: 	
		   No, the E-Bus switch must be ON in order for any of the accessories to operate. I will take another look at the diode polarity as well. One of the guys I am working with suggested I not turn on the E-Bus switch until After I start the engine.


	


The E-Bus should be energized with the E-Bus switch off and the master switch on.  If not, the diode is backwards.

  Although it will not hurt anything to fly with the E-Bus switch turned on, it is intended to be turned on only in the event that power is not available through the diode.

Joe



--------

Joe Gores





Read this topic online  here:



http://forums.matronics.com/viewtopic.php?p=361838#361838www.aeroelectric.com

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Dec 28, 2011 5:57 pm Post subject: First Engine Start Problem

At 07:39 PM 12/28/2011, you wrote:

 	  Quote: 	
		  Bob and Joe, thank you for pointing out both over loading ( I went 

back and read note 12) and the fact that the E-bus should be working 

with the Alternate switch off. To tell the truth, I have not tried 

it that way (w/just the Master on). If it does not work I do see 

that would mean the diode between the two buses is in backwards. I 

did check the diode position on the Batt Contactor and it IS 

installed the right way. I now have at the very least, some changing 

of circuits over to the Main bus. Will report back on findings after tomorrow.


	


    Blowing a fusible link is a rather non-trivial

    event. 22AWG wire is capable of considerable

    more current than the legacy rating in wire

    bundles of 5A would suggest.



    It would be interesting to get a real current

    measurement of all your goodies before you

    start moving things. Clip an ammeter across

    the alternate feed switch while the master

    switch is off.

   Bob . . .

dan(at)azshowersolutions.
Guest

Posted: Thu Dec 29, 2011 6:37 pm Post subject: First Engine Start Problem

Just got back from the airport and found the following:

1.I took the ammeter reading across the Alternate switch (with the Master switch off). I was reading at 5.2 A with everything on and that was without keying the mic for transmission. I assume that would bump it up even more (didn't get a chance to try that). 

2. The Diode between the two buses WAS backwards. I changed it and now my panel lights up when the Master switch is on. Would this have had any bearing on why my fuseable link burned or do you think I need to move some things to the Main bus? The components I have on the E-bus are as follows:

Dynon D100, Garmin 396, EIS (engine monitor), SL40 radio, Transponder, LED Becon and tail position light, Intercom, HZ Stab trim servo. I don't  have wing tip position/Nav lights yet but can probably put them on the main bus along with the other lights when I get them. The other thing I was toying with is moving the D-100 and the 396 over as they both have back-up batteries Thoughts or suggestions welcome.

Thanks,

Dan



[quote]       From: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com>

 To: aeroelectric-list(at)matronics.com 

 Sent: Wednesday, December  28, 2011 6:54 PM

 Subject: Re: Re: First Engine Start Problem

  

 --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>



At 07:39 PM 12/28/2011, you wrote:

 	  Quote: 	
		   Bob and Joe, thank you for pointing out both over loading ( I went back and read note 12) and the fact that the E-bus should be working with the Alternate switch off. To tell the truth, I have not tried it that way (w/just the Master on). If it does not work I do see that would mean the diode between the two buses is in backwards. I did check the diode position on the Batt Contactor and it IS installed the right way. I now have at the very least, some changing of circuits over to the Main bus. Will report back on findings after tomorrow.


	


   Blowing a fusible link is a rather non-trivial

   event. 22AWG wire is capable of considerable

   more current than the legacy rating in  wire

   bundles of 5A would suggest.



   It would be interesting to get a real current

   measurement of all your goodies before you

   start moving things. Clip an ammeter across

   the alternate feed switch while the master

   switch is off.

<="_blank" href="http://www.aeroelectric.com">www.aeroelectric.comhttp://www.ma======================



 

 

 [b]

user9253

Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan

Posted: Thu Dec 29, 2011 7:45 pm Post subject: Re: First Engine Start Problem

The diode being backwards was the reason the fusible link burned open.  Part of the starter current was going through the E-Bus circuit.  There is a saying that electricity takes the path of least resistance.  Even though there is a big fat wire going from the battery to the starter, that path is not the least resistance for ALL of the current.  Some of the current will find it easier to take parallel paths.  An analogy is highway traffic.  Most cars will take the multi-lane expressway.  But when traffic is very heavy and slows down, some cars will take side streets.  For them it is the path of least resistance.

  Your lighting circuit could be moved to the main bus.  The E-Bus should handle 5 amps OK.  The additional 2 amps while transmitting is of short duration and should not burn open the fusible link.  I will not be offended if Bob or anyone corrects me.

Joe

_________________
Joe Gores

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Dec 30, 2011 6:34 am Post subject: First Engine Start Problem

At 09:45 PM 12/29/2011, you wrote:

 --> AeroElectric-List message posted by: "user9253" <fran4sew(at)banyanol.com>



 The diode being backwards was the reason the fusible link burned open.  Part of the starter current was going through the E-Bus circuit.  There is a saying that electricity takes the path of least resistance.  Even though there is a big fat wire going from the battery to the starter, that path is not the least resistance for ALL of the current.  Some of the current will find it easier to take parallel paths.  An analogy is highway traffic.  Most cars will take the multi-lane expressway.  But when traffic is very heavy and slows down, some cars will take side streets.  For them it is the path of least resistance.



   Your lighting circuit could be moved to the main bus.  The E-Bus should handle 5 amps OK.  The additional 2 amps while transmitting is of short duration and should not burn open the fusible link.  I will not be offended if Bob or anyone corrects me.

  

     You are right on my friend. I will remind

     readers that the e-bus (while once erroneously

     called an "essential bus") was crafted

     for the purpose of keeping an alternator-

     out event from becoming an emergency. Hence,

     it was re-named the Endurance Bus.



     Successful and worry free application of

     the e-bus is dependent upon TWO things.

     (1) Knowing the minimum amount of energy

     stored in the battery and (2) knowing how

     many hours of flight are possible while

     being a good student of Energy Economics.



     One of my most cherished teachers, Thomas

     Sowell told me that economics is the study

     of scarce resources for which there are

     multiple uses. In this case, the scarce

     resource is watt-seconds of electrical

     energy available to run JUST the electro-

     whizzies most useful or en route operations.

     Once you have the airport of intended destination

     in sight, the scarcity of watt-seconds

     disappears.



     My personal design goal for sizing and

     powering the e-bus is to have more hours

     of en-route ops available from the electro-

     whizzies than I have fuel aboard. Everybody

     plans for there to be enough fuel for the

     mission leg . . . it seems that having

     a properly crafted e-bus is a good move

     for making a dead alternator a maintenance

     event as opposed to an emergency. Some

     years ago at Oshkosh, I suggested in one

     of my forums that system reliability is

     achieved when you can deal with any single

     failure without breaking a sweat.



     Since the people who own the airplanes

     I rent would not let me re-arrange their

     bus structures, my personal e-bus is powered

     by alkaline cells.



  http://tinyurl.com/4xjhgly 



     Whether I'm flying a J-3 or an A-36, I

     can confidently get where I want to go

     on an exceedingly austere budget of

     self contained watt-seconds.



     I recommend that the builder craft a

     Plan-B for alternator out-ops that includes

     periodic capacity checks to make sure that

     their battery's current state will carry

     e-bus loads for the duration of their 

     personal design goals. Whether that's 1 hour

     or duration of fuel aboard is your decision.

     But knowing WHAT it is an maintaining it

     is essential to the no-sweat management

     of an alternator-out event.



     You can obviously have more than necessary

     goodies on the e-bus . . . as long as they

     have ON-OFF switches. The goal is to have

     a plan for load-shedding in place that

     re-configures energy consumption to meet

     electrical endurance design goals.



     Over the years I've studied many "Dark-n-

     Stormy Night" stories and deduced that most

     if not all would never have been written

     had the pilot/author had (1) understanding

     and (2) an artfully crafted and maintained

     Plan-B.



 

   Bob . . .    [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Dec 30, 2011 8:30 am Post subject: First Engine Start Problem

At 08:33 PM 12/29/2011, you wrote:

 	  Quote: 	
		  Just got back from the airport and found the following:

1.I took the ammeter reading across the Alternate switch (with the 

Master switch off). I was reading at 5.2 A with everything on and 

that was without keying the mic for transmission. I assume that 

would bump it up even more (didn't get a chance to try that).


	


   Okay, how does 5.2A fit into your Plan-B?



 	  Quote: 	
		  2. The Diode between the two buses WAS backwards. I changed it and 

now my panel lights up when the Master switch is on. Would this have 

had any bearing on why my fuseable link burned or do you think I 

need to move some things to the Main bus? The components I have on 

the E-bus are as follows:

Dynon D100, Garmin 396, EIS (engine monitor), SL40 radio, 

Transponder, LED Becon and tail position light, Intercom, HZ Stab 

trim servo. I don't have wing tip position/Nav lights yet but can 

probably put them on the main bus along with the other lights when I 

get them. The other thing I was toying with is moving the D-100 and 

the 396 over as they both have back-up batteries Thoughts or 

suggestions welcome.


	


   See my earlier posting about Plan-B. You don't necessarily

   need to move anything. But you SHOULD have a check-list

   driven plan of action for responding to a low-voltage warning

   light. 5.2A may not be the Plan-B number. The lower you

   can make it, the more secure you are in dealing with an

   alternator failure.

   Bob . . .

Bob McC

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

Posted: Fri Dec 30, 2011 10:55 am Post subject: First Engine Start Problem

Dan;  

   

While the reversed diode is definitely the cause of the fused fusible link (in combination with having the alternate feed switch on) and installing the diode correctly will prevent the link failing in the future, (your loads are well within what the link will handle) this might also be an indication that there is a higher than desirable resistance in the “fat wire” circuit. Normally the resistance of the large wires and their connections is very very low and they should present the most attractive path for the starter current. However if one of the connections in this circuit is displaying relatively high resistance due to being loose or dirty or???? Then the parallel path through the miswired e-buss circuit might become more attractive and draw an unusually larger percentage of the starter current aggravating the scenario explained by Joe. It might be worth a simple voltage drop test across the fat wire circuit components while cranking to see if there are any joints or portions of that circuit displaying higher than normal resistance. If wired precisely per Z-16 then the likely source for the high resistance, if it exists, would be one of the connections to the battery contactor or the contactor itself. The other possibility of course is that if you tried to crank the engine with the reversed diode, the alternate feed “on” and the master switch “off” then full cranking current was attempting to pass through your fusible link and “poof”. Correctly installing the diode absolutely cures this possibility as well.  

   

Bob McC  

   

> -----Original Message-----  

> From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-  

> server(at)matronics.com] On Behalf Of user9253  

> Sent: Thursday, December 29, 2011 10:46 PM  

> To: aeroelectric-list(at)matronics.com  

> Subject: Re: First Engine Start Problem  

>   

> --> AeroElectric-List message posted by: "user9253" <fran4sew(at)banyanol.com>  

>   

> The diode being backwards was the reason the fusible link burned open.  Part of the  

> starter current was going through the E-Bus circuit.  There is a saying that electricity  

> takes the path of least resistance.  Even though there is a big fat wire going from the  

> battery to the starter, that path is not the least resistance for ALL of the current.  

> Some of the current will find it easier to take parallel paths.  An analogy is highway  

> traffic.  Most cars will take the multi-lane expressway.  But when traffic is very heavy  

> and slows down, some cars will take side streets.  For them it is the path of least  

> resistance.  

>   Your lighting circuit could be moved to the main bus.  The E-Bus should handle 5  

> amps OK.  The additional 2 amps while transmitting is of short duration and should  

> not burn open the fusible link.  I will not be offended if Bob or anyone corrects me.  

> Joe  

>   

> --------  

> Joe Gores  

>   

>   

>   

>   

> Read this topic online here:  

>   

> http://forums.matronics.com/viewtopic.php?p=361963#361963  

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_________________
Bob McC
Falco #908
(just starting)

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