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BMC_Dave

Joined: 04 Jul 2018
Posts: 40

Posted: Mon Jan 07, 2019 11:45 am Post subject: Z-12 Aux Alt Question

Taking a chance and posting my in-work Z-12 power architecture.



I'm trying to decide what behavior I want from my aux alt. Whether I want it to remain automatic or be manually switched. Bob had previously suggested using an additional LR3 regulator for an independently switched aux alt that was connected directly to the e-bus. I'm wondering if I move the aux alt to the e-bus can I continue to use the standby regulator provided in the B&C "Complete RV-10 bundle"? What effect will putting it behind the isolating diode from the main bus have, if any?



Thanks.

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nuckolls.bob(at)aeroelect
Guest

Posted: Mon Jan 07, 2019 5:25 pm Post subject: Z-12 Aux Alt Question

At 01:45 PM 1/7/2019, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "BMC_Dave" <bmcdave85(at)gmail.com>



 Taking a chance and posting my in-work Z-12 power architecture.



 I'm trying to decide what behavior I want from my aux alt. Whether I want it to remain automatic or be manually switched. Bob had previously suggested using an additional LR3 regulator for an independently switched aux alt that was connected directly to the e-bus. I'm wondering if I move the aux alt to the e-bus can I continue to use the standby regulator provided in the B&C "Complete RV-10 bundle"? What affect will putting it behind the isolating diode from the main bus have, if any?

 	


   Why move it to the e-bus? Z-12 allows either alternator

   to power the aircraft not unlike the FAA approved

   installations in TC aircraft. Given that the standby

   alternator is much more robust than the machines available

   when the e-bus was combined with the SD-8 for a 'minimalist'

   solution, there seems to be little value in putting an

   egg-beater to architectures that have proven to meet

   design goals for a couple decades now.



   What failure is best mitigated by moving the altenrator

   to the e-bus than by leaving it on the main bus?



   You can use either regulator . . . it's just that the

   SB1 running alone does not offer lv warning while

   the LR3 does. If you already have an SB1, then

   it wall suffice for the purpose of controlling

   the standby alternator.



 

 

   Bob . . .

BMC_Dave

Joined: 04 Jul 2018
Posts: 40

Posted: Mon Jan 07, 2019 6:21 pm Post subject: Re: Z-12 Aux Alt Question

 	  nuckolls.bob(at)aeroelect wrote: 	
		  At 01:45 PM 1/7/2019, you wrote:



   Why move it to the e-bus? 	




Primarily because the BC410-H standby alternator won't provide the 43.88 amps I need for IFR cruise for everything on the main bus. It seems reasonable to put the power generator on the e-bus for my electrically dependent engine as it's an easy way to isolate those critical components.

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Mon Jan 07, 2019 6:38 pm Post subject: Z-12 Aux Alt Question

That sounds like a fairly high continuous load. If I am in conditions to 

need pitot heat, all my avionics, nav lights, strobes and pitot heat 

totals about 23-24 amps. Adding landing light, which is not considered a 

continuous load only gets me up to 34 amps. That is with certified IFR 

GPS/nav/com, second nav com, ADS-B in and out equipment, two 10" 

EFIS/MFD screens, 2 axis autopilot, LED nav/strobe lights, 2 

incandescent landing lights. My load total includes a couple amps for 

charging the EFIS backup batteries. Old incandescent nav lights and tube 

type strobes instead of LEDs wouldn't get me to 40 amps.

IF you are into a standby alternator, the second nav/com can be turned 

off. The second EFIS screen could be turned off. Etc. A standby should 

not have to carry more than your essential load, not a full night-time 

IFR deice type of load.

On 1/7/2019 7:21 PM, BMC_Dave wrote:

 	  Quote: 	

 nuckolls.bob(at)aeroelect wrote:

> At 01:45 PM 1/7/2019, you wrote:

>

>     Why move it to the e-bus?

 Primarily because the BC410-H standby alternator won't provide the 43.88 amps I need for IFR cruise for everything on the main bus. It seems reasonable to put the power generator on the e-bus for my electrically dependent engine as it's an easy way to isolate those critical components.

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p=486811#486811

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

ceengland7(at)gmail.com
Guest

Posted: Mon Jan 07, 2019 8:04 pm Post subject: Z-12 Aux Alt Question

I'm not Dave, but one possible reason for the difference could be an 

electronic injection engine. The fuel pump alone will be around 6A. 

Another amp or two for ignition, and the injectors can peak at several 

amps each. Those are likely minimum numbers.

Charlie

On 1/7/2019 8:35 PM, Kelly McMullen wrote:

 	  Quote: 	

 <kellym(at)aviating.com>

 That sounds like a fairly high continuous load. If I am in conditions 

 to need pitot heat, all my avionics, nav lights, strobes and pitot 

 heat totals about 23-24 amps. Adding landing light, which is not 

 considered a continuous load only gets me up to 34 amps. That is with 

 certified IFR GPS/nav/com, second nav com, ADS-B in and out equipment, 

 two 10" EFIS/MFD screens, 2 axis autopilot, LED nav/strobe lights, 2 

 incandescent landing lights. My load total includes a couple amps for 

 charging the EFIS backup batteries. Old incandescent nav lights and 

 tube type strobes instead of LEDs wouldn't get me to 40 amps.

 IF you are into a standby alternator, the second nav/com can be turned 

 off. The second EFIS screen could be turned off. Etc. A standby should 

 not have to carry more than your essential load, not a full night-time 

 IFR deice type of load.

 On 1/7/2019 7:21 PM, BMC_Dave wrote:

> 

> <bmcdave85(at)gmail.com>

> nuckolls.bob(at)aeroelect wrote:

>> At 01:45 PM 1/7/2019, you wrote:

>>

>>     Why move it to the e-bus?

> Primarily because the BC410-H standby alternator won't provide the 

> 43.88 amps I need for IFR cruise for everything on the main bus. It 

> seems reasonable to put the power generator on the e-bus for my 

> electrically dependent engine as it's an easy way to isolate those 

> critical components.

>

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BMC_Dave

Joined: 04 Jul 2018
Posts: 40

Posted: Mon Jan 07, 2019 8:05 pm Post subject: Re: Z-12 Aux Alt Question

I agree it is a high continuous load, nevertheless that's what's required. Albeit with a little headroom on some things (lights, for example).



ETA: EFI is more like 16A max for all cases, so these numbers need to be even higher...

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Tundra10

Joined: 14 Jun 2010
Posts: 102
Location: Scarborough, Ontario

Posted: Tue Jan 08, 2019 7:05 am Post subject: Re: Z-12 Aux Alt Question

You may have already caught this, but the feed to the aux alternator field needs to come from the endurance bus, or the alternator won’t work while the main bus is turned off.



Jeff Page

Dream Aircraft Tundra #10

BMC_Dave

Joined: 04 Jul 2018
Posts: 40

Posted: Tue Jan 08, 2019 8:05 am Post subject: Re: Z-12 Aux Alt Question

 	  Tundra10 wrote: 	
		  You may have already caught this, but the feed to the aux alternator field needs to come from the endurance bus, or the alternator won’t work while the main bus is turned off.



Jeff Page

Dream Aircraft Tundra #10 	




Correct, but thanks for pointing that out.



Hopefully I've adequately articulated my need for a separate endurance bus with its own power generating capabilities, given my electrically dependent engine.



If the standby alt is on the e-bus, then when the main alt goes offline the standby will still be regulated by the battery voltage but would be unable to charge it unless the e-bus alt feed was closed. Is it advantageous to leave the e-bus alt feed closed for normal ops then? If that were the case would I want to switch that relay to another contactor?



Also if I'm understanding correctly the recommendation is to run two LR3 units instead of the LR3 on the main and SB1 on aux? Presumably I'd set the standby LR3 voltage lower than the main and if the main goes offline the standby would automatically come up and start powering the e-bus?



Just want to run through the functionality and make sure I'm understanding it correctly, thanks.

BMC_Dave

Joined: 04 Jul 2018
Posts: 40

Posted: Tue Jan 08, 2019 9:35 am Post subject: Re: Z-12 Aux Alt Question

Looking at B&C's offerings it seems they have a standby alt that will make 41.3 amps at my IO-540s cruise RPM, I don't recall seeing these on their site in the recent past?



Anyway since it seems one of these would (nearly) power my entire system I don't need a separate endurance bus, that would be the preferred route.

Tundra10

Joined: 14 Jun 2010
Posts: 102
Location: Scarborough, Ontario

Posted: Tue Jan 08, 2019 9:44 am Post subject: Re: Z-12 Aux Alt Question

It is the choice of approach many of us struggle with (at least I do).



On one hand, there is the concept of a failed alternator triggering use of an endurance bus, so you don't have to choose what equipment can be supported for a pre-determined period of time on a battery with a known good state, or indefinitely on a second alternator with smaller capacity.



On the other hand was the procedure we all learned initially training on a Cessna.  In the case of fire, turn off the master and land in a field.  With an electrically dependent engine we need a way to shut off everything except electronic ignition, electronic fuel injection and fuel pumps with a single switch.



If you plan to routinely fly IFR, then most of everything ends up on the endurance bus, leaving a landing light and a couple of other things on the main bus.  In case of fire, turning off the main contactor to run on the endurance bus may not isolate the fault.



The minimum equipment to fly day VFR to the next point of intended landing is easy.  With an IFR equipped plane, the minimum equipment to do that will vary a lot depending on the flight conditions at the time.  To me, a low voltage warning light is very important, since in that situation, you can selectively turn off devices not needed at the time until the light goes out, indicating the secondary alternator is capable of indefinitely carrying the selected load.  Not as easy as just flicking off the main contactor and going on the endurance bus, but still simple enough that major troubleshooting is not required.



As far as automatic fail over to the second alternator goes, there is no rush.  The battery will not significantly discharge during the couple of minutes it might take to notice the low voltage warning indicator and you manually activating the endurance bus and the second alternator.



The evolution of my electrical architecture has gone from an elaborate setup, to Z13 with way too much stuff on the endurance bus, to most of it back on the main bus.



Once you choose your approach, the rest will fall into place more easily.



Jeff Page

Dream Aircraft Tundra #10

BMC_Dave

Joined: 04 Jul 2018
Posts: 40

Posted: Tue Jan 08, 2019 10:51 am Post subject: Re: Z-12 Aux Alt Question

 	  Tundra10 wrote: 	
		  It is the choice of approach many of us struggle with (at least I do).



On one hand, there is the concept of a failed alternator triggering use of an endurance bus, so you don't have to choose what equipment can be supported for a pre-determined period of time on a battery with a known good state, or indefinitely on a second alternator with smaller capacity.



On the other hand was the procedure we all learned initially training on a Cessna.  In the case of fire, turn off the master and land in a field.  With an electrically dependent engine we need a way to shut off everything except electronic ignition, electronic fuel injection and fuel pumps with a single switch.



If you plan to routinely fly IFR, then most of everything ends up on the endurance bus, leaving a landing light and a couple of other things on the main bus.  In case of fire, turning off the main contactor to run on the endurance bus may not isolate the fault.



The minimum equipment to fly day VFR to the next point of intended landing is easy.  With an IFR equipped plane, the minimum equipment to do that will vary a lot depending on the flight conditions at the time.  To me, a low voltage warning light is very important, since in that situation, you can selectively turn off devices not needed at the time until the light goes out, indicating the secondary alternator is capable of indefinitely carrying the selected load.  Not as easy as just flicking off the main contactor and going on the endurance bus, but still simple enough that major troubleshooting is not required.



As far as automatic fail over to the second alternator goes, there is no rush.  The battery will not significantly discharge during the couple of minutes it might take to notice the low voltage warning indicator and you manually activating the endurance bus and the second alternator.



The evolution of my electrical architecture has gone from an elaborate setup, to Z13 with way too much stuff on the endurance bus, to most of it back on the main bus.



Once you choose your approach, the rest will fall into place more easily.



Jeff Page

Dream Aircraft Tundra #10 	




Yeah this basically sums up my process so far. I'm setting up for IFR and did find I needed most things like you said.



A single bus, battery, and dual alternators seem like the simplest route that will provide enough redundancy for my comfort.



The only thing I see now is the single battery contactor. I recall discussions either here or on VAF about B&C alternators continuing to run should they lose the battery connection, so it sounds like my panel wouldn't just go dark if that were to happen (ignoring EFIS battery backups).



Would be prudent to provide a redundant battery path, perhaps two contactors in parallel? I know you've all said contactor failures are rare, and that they also corrode quite significantly with age.

supik

Joined: 22 Aug 2018
Posts: 70

Posted: Tue Jan 08, 2019 12:24 pm Post subject: Re: Z-12 Aux Alt Question

 	  BMC_Dave wrote: 	
		  



The only thing I see now is the single battery contactor. I recall discussions either here or on VAF about B&C alternators continuing to run should they lose the battery connection, so it sounds like my panel wouldn't just go dark if that were to happen (ignoring EFIS battery backups). 	




This is true in case the alternator is feeding the very same bus from where it is being operated or that bus is closed to the bus fed from the alt.



Edit: Without the battery it will provide you with 'nonstable' power from the alt, big capacitor battery is missing which is no good for the avionics.

_________________
Igor

RV10 in progress

supik

Joined: 22 Aug 2018
Posts: 70

Posted: Tue Jan 08, 2019 1:38 pm Post subject: Re: Z-12 Aux Alt Question

 	  Tundra10 wrote: 	
		  It is the choice of approach many of us struggle with (at least I do).



On one hand, there is the concept of a failed alternator triggering use of an endurance bus, so you don't have to choose what equipment can be supported for a pre-determined period of time on a battery with a known good state, or indefinitely on a second alternator with smaller capacity.



On the other hand was the procedure we all learned initially training on a Cessna.  In the case of fire, turn off the master and land in a field.  With an electrically dependent engine we need a way to shut off everything except electronic ignition, electronic fuel injection and fuel pumps with a single switch.



If you plan to routinely fly IFR, then most of everything ends up on the endurance bus, leaving a landing light and a couple of other things on the main bus.  In case of fire, turning off the main contactor to run on the endurance bus may not isolate the fault.



The minimum equipment to fly day VFR to the next point of intended landing is easy.  With an IFR equipped plane, the minimum equipment to do that will vary a lot depending on the flight conditions at the time.  To me, a low voltage warning light is very important, since in that situation, you can selectively turn off devices not needed at the time until the light goes out, indicating the secondary alternator is capable of indefinitely carrying the selected load.  Not as easy as just flicking off the main contactor and going on the endurance bus, but still simple enough that major troubleshooting is not required.



As far as automatic fail over to the second alternator goes, there is no rush.  The battery will not significantly discharge during the couple of minutes it might take to notice the low voltage warning indicator and you manually activating the endurance bus and the second alternator.



The evolution of my electrical architecture has gone from an elaborate setup, to Z13 with way too much stuff on the endurance bus, to most of it back on the main bus.



Once you choose your approach, the rest will fall into place more easily.



Jeff Page

Dream Aircraft Tundra #10 	




Very good point, I am just there, going through the same dilemma.. However at this stage of my knowledge (might change in near future  I like the idea of the e-bus as long as you are not going with Z-14.



- It helps with shedding loads immediately without loosing precious time especially with a dual alternator failure or mismanagement (very unlikely but.. -it's not always technical failure, human error is a known factor and maybe one day these planes will be flown by people who did not design them, so have less systems knowledge with a combination of bad day.)



- You can always continue with shedding/switching of remaining equipment on the e-bus if needed.



- With my current design in case of electrical smoke I plan to isolate the equipment as follows:



1 Verify E-Bus ON (plan to keep it always ON)

2 Master OFF 

3 AVIONICS 1 OFF (fed from EBUS)

 (this leaves me only with one PFD & backup EFIS + Garmin GAD29, GEA24, AHARS

NOTE: AVIONICS 2 is fed from MAIN PWR DISTRIBUTION BUS



IF smoke continues:

4 EBUS -OFF (only backup EFIS with own battery available)

In case of ALT 1 (main) failure, again quickly shed loads with MASTER OFF. Provided the E-BUS is ON.



It really might be useful in demanding situations when your head is busy flying IFR, talking to ATC, handling a non standard situation in bad wx at night )))))))))

_________________
Igor

RV10 in progress

BMC_Dave

Joined: 04 Jul 2018
Posts: 40

Posted: Tue Jan 08, 2019 2:59 pm Post subject: Re: Z-12 Aux Alt Question

Yeah I'm still torn. Having a single bus leaves no ability to isolate components, but like was mentioned continued IFR flight requires almost everything on the e-bus anyway. A single bus also means my EFIS backup batteries are now only used for brownout protection (I'm unsure if they can be manually told to use their batteries instead of ship power).



Have to think on this a bit more.

supik

Joined: 22 Aug 2018
Posts: 70

Posted: Tue Jan 08, 2019 3:20 pm Post subject: Re: Z-12 Aux Alt Question

Personally if anything major goes wrong electrically and I am in IMC, I will look for a good enroute alternate airport with best wx in the area and land. Airmanship of course, if it's close to minimums below me and my original destination has way better wx, then continue.



On the ground, I will have plenty of time to check the systems, perform repairs if possible, wait for better wx and make further decisions. If the degraded system allows for a safe VFR flight, one can continue home or to destination.

_________________
Igor

RV10 in progress

ceengland7(at)gmail.com
Guest

Posted: Tue Jan 08, 2019 6:16 pm Post subject: Z-12 Aux Alt Question

On 1/8/2019 5:20 PM, supik wrote:

 	  Quote: 	
		   



 Personally if anything major goes wrong electrically and I am in IMC, I will look for a good enroute alternate airport with best wx in the area and land. Airmanship of course, if it's close to minimums below me and my original destination has way better wx, then continue.



 On the ground, I will have plenty of time to check the systems, perform repairs if possible, wait for better wx and make further decisions. If the degraded system allows for a safe VFR flight, one can continue home or to destination.



 --------

 Igor



 RV10 in progress



As a FWIW, I tried to come as close as reasonably possible to 
	


'conventional' operation: airframe power is on one switch (the master), 

and the engine on another. Sustained smoke in the cockpit in 

'conventional' is master off NOW, & find the ground.

My (not-yet-flying) electrically dependent alt engine has all it needs 

on its very own bus, controlled by its own switch.

Everything else is on the other (airframe) bus.

Dual identical alternators, one feeding each bus.

(Cross-tie switch to allow either bus to be powered by the other, in 

case of control (switch or contactor) failure.)



Response to sustained smoke would be 'airframe master off, hunt for 

ground', with the EFIS kept alive by its internal battery.



No claim that this is the best solution. Just that it at least 

marginally mimics conventional operation and hopefully, will allow long 

conditioned responses in a high stress situation.



Charlie



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supik

Joined: 22 Aug 2018
Posts: 70

Posted: Wed Jan 09, 2019 3:15 am Post subject: Re: Z-12 Aux Alt Question

 	  ceengland7(at)gmail.com wrote: 	
		  On 1/8/2019 5:20 PM, supik wrote:

 	  Quote: 	
		   



 Personally if anything major goes wrong electrically and I am in IMC, I will look for a good enroute alternate airport with best wx in the area and land. Airmanship of course, if it's close to minimums below me and my original destination has way better wx, then continue.



 On the ground, I will have plenty of time to check the systems, perform repairs if possible, wait for better wx and make further decisions. If the degraded system allows for a safe VFR flight, one can continue home or to destination.



 --------

 Igor



 RV10 in progress



As a FWIW, I tried to come as close as reasonably possible to 

	


'conventional' operation: airframe power is on one switch (the master), 

and the engine on another. Sustained smoke in the cockpit in 

'conventional' is master off NOW, & find the ground.

My (not-yet-flying) electrically dependent alt engine has all it needs 

on its very own bus, controlled by its own switch.

Everything else is on the other (airframe) bus.

Dual identical alternators, one feeding each bus.

(Cross-tie switch to allow either bus to be powered by the other, in 

case of control (switch or contactor) failure.)



Response to sustained smoke would be 'airframe master off, hunt for 

ground', with the EFIS kept alive by its internal battery.



No claim that this is the best solution. Just that it at least 

marginally mimics conventional operation and hopefully, will allow long 

conditioned responses in a high stress situation.



Charlie



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Good approach!

_________________
Igor

RV10 in progress

BMC_Dave

Joined: 04 Jul 2018
Posts: 40

Posted: Wed Jan 09, 2019 10:53 am Post subject: Re: Z-12 Aux Alt Question

 	  ceengland7(at)gmail.com wrote: 	
		  

'conventional' operation: airframe power is on one switch (the master), 

and the engine on another. Sustained smoke in the cockpit in 

'conventional' is master off NOW, & find the ground.

My (not-yet-flying) electrically dependent alt engine has all it needs 

on its very own bus, controlled by its own switch.

Everything else is on the other (airframe) bus.

Dual identical alternators, one feeding each bus.

(Cross-tie switch to allow either bus to be powered by the other, in 

case of control (switch or contactor) failure.)



Response to sustained smoke would be 'airframe master off, hunt for 

ground', with the EFIS kept alive by its internal battery.



No claim that this is the best solution. Just that it at least 

marginally mimics conventional operation and hopefully, will allow long 

conditioned responses in a high stress situation.



Charlie



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I agree with the idea of emulating "conventional" operation.



My originally posted architecture might be nearly there, if I move non-engine stuff to the main bus.



Smoke in cockpit, e-bus alt feed on, master off. Engine will run for 2+ hours in that condition, and I can alternate between primary and backup EFISs for a nominal 2.5 hours of flight instrument time. Pitot heat reduces engine run time to a little over an hour.



I don't have a lot of experience in hard IMC as I'm not instrument rated, but it seems to me the scenario where I have a dual alternator failure and the pitot is icing up I'd be in an emergency and on my way to a landing. Still noodling if 1 hour is good enough for me here.



Only thing is I would be isolated from the outside world then, so maybe leave the 430 on the e-bus as well so I have a means to communicate but can still switch it off.



Boy I'd sure love to just move a smaller aux alt to the e-bus...

glastar(at)gmx.net
Guest

Posted: Thu Jan 10, 2019 1:36 am Post subject: Z-12 Aux Alt Question

Charlie,



not sure about the details, but would it not be prudent to have half of 

your engine power on each bus (if the engine has supported dual 

ignition/injection etc.), when you try to detect what is wrong you would 

still have half of your electrical dependent engine power on when 

shutting down one bus?

As if something on your engine bus goes wrong you have only the choice 

to shut it down .



Just a thought.



Cheers Werner



On 09.01.2019 03:17, Charlie England wrote:

 	  Quote: 	
		  

>

 As a FWIW, I tried to come as close as reasonably possible to 

 'conventional' operation: airframe power is on one switch (the 

 master), and the engine on another. Sustained smoke in the cockpit in 

 'conventional' is master off NOW, & find the ground.

 My (not-yet-flying) electrically dependent alt engine has all it needs 

 on its very own bus, controlled by its own switch.

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