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andymeyer

Joined: 31 Mar 2015
Posts: 54
Location: SW MI

Posted: Fri May 06, 2022 1:17 pm Post subject: Too many Circuit breakers....

I'm doing a panel upgrade in my Long EZ and have a lot of breakers - I shouldn't need this many. I do prefer breakers as I can disable items - especially when working on one system or another, but there's not a ton of space in a Long EZ panel. 



Right now, I'm counting 16 breakers - way too many... What can I group, and are some things better left to a fuse? Garmin and Avidyne say not to group, but there's quite a few breakers here! 



Accessory (USB charger, etc...)

ADS-B - Stratux

ALTernator (LR3D)

Autopilot (GMC507 + 2 servos)

Audio (GM345)

AV-30E (Backup attitude, plus full time traffic display)

ELT (ACK-E04)

Engine Monitor (Home built)

GAD29C

GDU470

GMU11

IFD540 - COMM

IFD540 - GNS

Ignition 1 (Lightspeed Plasma 3)

Ignition 2 (Lightspeed Plasma 3)

Transponder (AXP-322)

Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Fri May 06, 2022 1:48 pm Post subject: Too many Circuit breakers....

On Fri, May 6, 2022 at 4:21 PM andymeyer <meyerkc135(at)gmail.com (meyerkc135(at)gmail.com)> wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: "andymeyer" <meyerkc135(at)gmail.com (meyerkc135(at)gmail.com)>

 

 I'm doing a panel upgrade in my Long EZ and have a lot of breakers - I shouldn't need this many. I do prefer breakers as I can disable items - especially when working on one system or another, but there's not a ton of space in a Long EZ panel. 

 

 Right now, I'm counting 16 breakers - way too many... What can I group, and are some things better left to a fuse? Garmin and Avidyne say not to group, but there's quite a few breakers here! 

 

 Accessory (USB charger, etc...)

 ADS-B - Stratux

 ALTernator (LR3D)

 Autopilot (GMC507 + 2 servos)

 Audio (GM345)

 AV-30E (Backup attitude, plus full time traffic display)

 ELT (ACK-E04)

 Engine Monitor (Home built)

 GAD29C

 GDU470

 GMU11

 IFD540 - COMM

 IFD540 - GNS

 Ignition 1 (Lightspeed Plasma 3)

 Ignition 2 (Lightspeed Plasma 3)

 Transponder (AXP-322)

	
Â  

 

By 'group', do you mean putting multiple items on one protection device? The only answer is the additional devices you don't mind losing if something on the same circuit trips the circuit protection.

My strong preference is a big ATC fuse bus(es) mounted somewhereÂ out of the way, so I don't have to make that call,Â and more importantly, I'm never tempted to play withÂ them in the air. A fuse legend and a little plastic fuse puller is all that's needed to disable an individual circuit, though I rarely find the need to do that during maintenance. The only thing on that list that I'd put on a breaker is the alternator field supply.

FWIW,

Charlie

_________________
Charlie

nuckolls.bob(at)aeroelect
Guest

Posted: Sat May 07, 2022 7:26 am Post subject: Too many Circuit breakers....

 	  Quote: 	
		  

 By 'group', do you mean putting multiple items on one protection device? The only answer is the additional devices you don't mind losing if something on the same circuit trips the circuit protection.

 	


   Generally a no-no in the big iron bird factories



  	  Quote: 	
		  My strong preference is a big ATC fuse bus(es) mounted somewhereÂ out of the way, so I don't have to make that call,Â and more importantly, I'm never tempted to play withÂ them in the air. A fuse legend and a little plastic fuse puller is all that's needed to disable an individual circuit, though I rarely find the need to do that during maintenance. 	


   Hear hear! See  http://aeroelectric.com/articles/fusvsbkr.html

                  

                   http://aeroelectric.com/articles/fuseorcb.html



   99.99% of all breakers and fuses go to the bone yard when

   the airplane is scrapped NEVER having been called upon

   to save the wire it feeds. Yet much cost of ownership

   and valuable panel space is dedicated to breaker-farms.



   Do yourself a favor and tuck a fat fuse-block away

   with protection on EVERY dedicated feeder . . . make

   the block big enough to have some spares for future

   expansion.



 

  	  Quote: 	
		  The only thing on that list that I'd put on a breaker is the alternator field supply. 	


   But even this is not necessary if you have something

   other than crowbar ov management.



 



 

   Bob . . .



   Un impeachable logic: George Carlin asked, "If black boxes

   survive crashes, why don't they make the whole airplane

   out of that stuff?"

user9253

Joined: 28 Mar 2008
Posts: 1922
Location: Riley TWP Michigan

Posted: Sat May 07, 2022 8:32 am Post subject: Re: Too many Circuit breakers....

I will add my vote for fuses to those of Bob and Charlie.

A whole fuse block with fuses might cost less than one breaker.

Circuit breakers are mechanical devices that can fail either open or closed.

I tested a circuit breaker on the bench prior to installation.  It smoked instead of opening.  I decided not to install a circuit breaker.

Fuses never fail to open when overloaded.

Fuses don't need to be installed on the instrument panel.

Fuses weigh less than breakers.

Each electrical load should have its own unique fuse.  If it blows, only one load is lost.  And you will know which circuit has the fault.

Never reset a circuit breaker or replace a fuse while airborne.  Do troubleshooting when safely on the ground.

A wise man once said, "That tripped breaker or blown fuse just prevented smoke and fire.  Do you want to give the fire a second chance?"

_________________
Joe Gores

andymeyer

Joined: 31 Mar 2015
Posts: 54
Location: SW MI

Posted: Sat May 07, 2022 11:54 am Post subject: Re: Too many Circuit breakers....

Alright - looks like I might have some breakers to sell.

What's an ideal fuse block model for the ATC fuses. Any good brand or model suggested? I'm scared of some of the stuff I see.

 	  nuckolls.bob(at)aeroelect wrote: 	
		  

 

  	  Quote: 	
		  The only thing on that list that I'd put on a breaker is the alternator field supply. 	


   But even this is not necessary if you have something

   other than crowbar ov management.

	


Do I read this as: Since I've got the LR3D I don't need a breaker for the alternator even though BandC calls for one? Just put a fuse where they call for breakers?



My ignitions - 2 Lightspeeds - What's the best protection for the wires running from the panel to the back seat? I still need switches to turn them on or off, might I be better off with a W31 Breaker switch and that be it, or is the complexity of the W31 a risk? Part of me would like to be able to reset it if the engine goes quiet and I'm out of other options. Though 2 dying at once seems highly improbable.



Radio Master (Currently a W31 breaker switch) - people seem to be moving away from avionics masters - is that really the best case these days? Let the Garmin and Avidyne stuff suffer the brown-out during start and reboot? Or go around twisting knobs off and on? I'd like to be able to get rid of as much load during start. Normally, only things I have is LED Nav lights and the engine monitor. (Engine monitor only needs ~4 volts to run)



And Autopilot disable - Do I install a switch to pull power from it, or trust the interface and electrons to behave?



Thanks Charlie, Bob and Joe!

Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Sat May 07, 2022 12:52 pm Post subject: Too many Circuit breakers....

A lot of us are using Bussmann 15600-X-20 ATC Fuse Panels, like this:

https://www.amazon.com/Bussmann-15600-12-20-Fuse-Block-Assembly/dp/B001PYQP0E/ref=pd_lpo_2?pd_rd_i=B001PYQP0E&psc=1

The 'X' denotes the number of fuses in the block. From 4 (or maybe 2) up 

to at least 18 fuses per block.

https://www.ebay.com/itm/284540458393?epid=1585402948&hash=item423feed599:g:T8AAAOSwLnBX2~T4

Bussmann also makes one with the wire exit on the bottom, but it 

requires a dedicated crimper for the terminals. The 15600 has standard 

1/4" blades for output terminals, so a regular PIDG crimper works for 

the mating connectors.

I've not used any of them, but I'd expect any of the well known marine 

vendors using ATC style fuses would be fine, too.

Charlie

On 5/7/2022 2:54 PM, andymeyer wrote:

 	  Quote: 	

 Alright - looks like I might have some breakers to sell.

 What's an ideal fuse block model for the ATC fuses. Any good brand or model suggested? I'm scared of some of the stuff I see.

 nuckolls.bob(at)aeroelect wrote:

>   

>   

>> The only thing on that list that I'd put on a breaker is the alternator field supply.

>     But even this is not necessary if you have something

>     other than crowbar ov management.

>

 Do I read this as: Since I've got the LR3D I don't need a breaker for the alternator even though BandC calls for one? Just put a fuse where they call for breakers?

 My ignitions - 2 Lightspeeds - What's the best protection for the wires running from the panel to the back seat? I still need switches to turn them on or off, might I be better off with a W31 Breaker switch and that be it, or is the complexity of the W31 a risk? Part of me would like to be able to reset it if the engine goes quiet and I'm out of other options. Though 2 dying at once seems highly improbable.

 Radio Master (Currently a W31 breaker switch) - people seem to be moving away from avionics masters - is that really the best case these days? Let the Garmin and Avidyne stuff suffer the brown-out during start and reboot? Or go around twisting knobs off and on? I'd like to be able to get rid of as much load during start. Normally, only things I have is LED Nav lights and the engine monitor. (Engine monitor only needs ~4 volts to run)

 Thanks Charlie, Bob and Joe!

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_________________
Charlie

user9253

Joined: 28 Mar 2008
Posts: 1922
Location: Riley TWP Michigan

Posted: Sat May 07, 2022 2:54 pm Post subject: Re: Too many Circuit breakers....

I don't like those Busman fuse blocks.  They don't grip the fuses as tightly as I would like.  And the wires stick out to the sides which takes too much space.  Look for a fuse block that has the wires exiting from the back side.

Read this thread http://forums.matronics.com/viewtopic.php?t=16762261

Pay attention to what Stein posts.  He owns a well respected avionics shop.

_________________
Joe Gores

user9253

Joined: 28 Mar 2008
Posts: 1922
Location: Riley TWP Michigan

Posted: Sat May 07, 2022 3:10 pm Post subject: Re: Too many Circuit breakers....

I don't have any experience with these, but the wires exit the back side.

https://www.aircraftspruce.com/catalog/pnpages/11-13348.php

https://www.connectorconcepts.com/bu15reteatcf4.html

_________________
Joe Gores

Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Sat May 07, 2022 5:02 pm Post subject: Too many Circuit breakers....

On 5/7/2022 5:54 PM, user9253 wrote:

 	  Quote: 	
		   



 I don't like those Busman fuse blocks.  They don't grip the fuses as tightly as I would like.  And the wires stick out to the sides which takes too much space.  Look for a fuse block that has the wires exiting from the back side.

 Read this thread http://forums.matronics.com/viewtopic.php?t=16762261

 Pay attention to what Stein posts.  He owns a well respected avionics shop.



 --------

 Joe Gores

Hi Joe,
	




Your mileage obviously varies, from mine & a lot of others.Â  



I've got 3 of them in my RV-7 project, and a couple in my flying RV-6. 

Maybe I'm a wimp, but I can't pull a fuse without using the 

purpose-built puller or a pair of pliers. A lot of guys are using them 

in flying experimentals, mounted with the fuses facing down, for 

hundreds of hours without losing any fuses.



Maybe you got a bad one, or one that someone else had abused?



Charlie



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_________________
Charlie

andymeyer

Joined: 31 Mar 2015
Posts: 54
Location: SW MI

Posted: Sat May 07, 2022 7:19 pm Post subject: Re: Too many Circuit breakers....

Alright - I'm down to 7 breakers, plus 4 W31's...



Any thoughts on the Avionics Master? - Yes? No? Either way?



Breakers:

Alternator

Ignition 1

Ignition 2

Engine Instruments (This is home built so I want to be able to reset if needed)

Transponder (in case I need to go quiet, formation, etc... It's remote only - breaker is a fast switch)

Audio (In case I get a loud squeal or otherwise, I can get it out of the system)

Autopilot (In case it misbehaves)



W31's are switches/breakers for the following - (been in their for the same function for ~20 years) All could be switches and if the W31's give up the ghost, they will become switches / fuses:

Pitot Heat

Nav lights

Landing Light

Boost Pump



Thanks for helping me with the simplification - I'm liking this a lot better and gaining a lot of comfort!



Andy

user9253

Joined: 28 Mar 2008
Posts: 1922
Location: Riley TWP Michigan

Posted: Sun May 08, 2022 3:29 am Post subject: Re: Too many Circuit breakers....

Charlie, Maybe my Busman fuse block was defective or maybe I am too much of a perfectionist.  But the fuses did not require much force to pull out.  The spring contacts only gripped the fuse at one location.  I made my own fuse block using contacts similar to spade connectors which grip the fuse on two edges.  See Mouser part number 534-3522.  I have to use a tool to pull a fuse out.

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_________________
Joe Gores

user9253

Joined: 28 Mar 2008
Posts: 1922
Location: Riley TWP Michigan

Posted: Sun May 08, 2022 4:16 am Post subject: Re: Too many Circuit breakers....

Andy, read this http://www.aeroelectric.com/articles/avmaster.pdf

An avionics master switch is an unnecessary failure point.  If it fails, all avionics are lost.  If not installed, it can not fail.

There are no voltage spikes that can damage avionics during engine starting.

There is a voltage sag during starting that might cause avionics to reboot.  But voltage sag while cranking the engine will not damage avionics.

Some pilots argue that they don't want to wear out individual avionics switches, so they install an avionics master switch.  Actually, switches need to be exercised to wear away corrosion.  Switches are designed to be operated tens of thousands of times.  How many times will you operate avionics switches during your lifetime?

My airplane does not have an avionics master switch.  I leave all avionics turned on during engine start.  I have started my plane hundreds of times over the past 11 years.  All avionics still work fine.

_________________
Joe Gores

Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Sun May 08, 2022 5:04 am Post subject: Too many Circuit breakers....

On Sun, May 8, 2022 at 7:42 AM user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>

 

 Charlie, Maybe my Busman fuse block was defective or maybe I am too much of a perfectionist.Â  But the fuses did not require much force to pull out.Â  The spring contacts only gripped the fuse at one location.Â  I made my own fuse block using contacts similar to spade connectors which grip the fuse on two edges.Â  See Mouser part number 534-3522.Â  I have to use a tool to pull a fuse out.

 

 --------

 Joe Gores



	
This is what the Bussmann looks like inside. (I 'modded' one to have two buses in one block.)

Â

fuse_block_mod_tab_soldered_assembled_(Small).jpg

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_________________
Charlie

Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Sun May 08, 2022 5:36 am Post subject: Too many Circuit breakers....

On Sat, May 7, 2022 at 11:10 PM andymeyer <meyerkc135(at)gmail.com (meyerkc135(at)gmail.com)> wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: "andymeyer" <meyerkc135(at)gmail.com (meyerkc135(at)gmail.com)>

 

 Alright - I'm down to 7 breakers, plus 4 W31's...

 

 Any thoughts on the Avionics Master? - Yes? No? Either way?

 

 Breakers:

 Alternator

 Ignition 1

 Ignition 2

 Engine Instruments (This is home built so I want to be able to reset if needed)

 Transponder (in case I need to go quiet, formation, etc... It's remote only - breaker is a fast switch)

 Audio (In case I get a loud squeal or otherwise, I can get it out of the system)

 Autopilot (In case it misbehaves)

 

 W31's are switches/breakers for the following - (been in their for the same function for ~20 years) All could be switches and if the W31's give up the ghost, they will become switches / fuses:

 Pitot Heat

 Nav lights

 Landing Light

 Boost Pump

 

 Thanks for helping me with the simplification - I'm liking this a lot better and gaining a lot of comfort!

 

 Andy 	
My philosophy on stuff that keeps the engine running is that it should be independent of any a/c bus, just like conventional carb/mags engines are. What does the electronic engine mfgr say about how to supply power to the ignitions? There's one full bore controller mfgr (that I'd never consider using) that advises stuff that's truly scary, but most tell you to run the ignition supply directly from the battery, ahead of any master contactor, etc. If you do that, in my mindÂ  fusible links (at the battery)Â are by far the most bullet-proof system to protect the wire with no chance of a 'nuisance trip'.

If we ignore the fact that you already have the CBs, nothing on that list would have a breaker in my plane, except the alternator field, and that only because I'm using crowbar style overvoltage protection. AlmostÂ anything that needs to be switched can be controlled with a switch that will be cheaper, lighter, and likely more reliable than a CB; especially a combo switch/breaker.Â 

For me, any decision about an avionics master would be driven by operational convenience, and whether I need the ability to load-shed, in a failed alternator situation. In the totally electrically dependent plane I'm building, I have dual identical alternators, so load shedding isn't an issue. I therefore have an engine master, that controls the bus that powers the engine, and an airframe bus, that powers the rest of the plane. I suppose we could call the airframe bus an 'avionics bus', but it's really everything except the stuff that keeps the engine running. There's a bus-tie switch that can power the engine bus from the airframe bus, as backup if something in the engine master circuit fails.

If you need to shed loads for alternator-out, then putting all non-essential stuff on a separate switched bus would make sense.

There's also the issue of 'brownout' and rebooting at engine start. If that's an inconvenience, you can pick between letting everything boot at master-on and use a brownout booster, or usingÂ  an avionics master & powering the avionics after engine start. I only had one thing (an EFIS) in my current flying a/c that rebooted at engine start, so I made a brownout booster using a little $5 'boost' regulator, wired to the supply and to a diode-isolated power input on the EFIS.Â 

I do have an 'essential' bus in the flying a/c that can be left powered up if I need to turn off the master to conserve battery energy (the flying a/c has only one alternator). The essential bus makes it basically a one step operation to shed nonessential loads, instead of having to individually turn off stuff, which could be overlooked in a stressed environment.

Charlie

_________________
Charlie

andymeyer

Joined: 31 Mar 2015
Posts: 54
Location: SW MI

Posted: Sun May 08, 2022 7:59 pm Post subject: Re: Too many Circuit breakers....

Alright...

Down to 4 breakers which may turn into switches... Engine Monitor, Transponder, Audio panel (remote) and the autopilot. Those are things I feel I must be able to shut down hard.



My engine monitor so I can reset the thing - didn't design a reset input into the PCBA, though that may come with the next board turn. Just ordered the PCBA's 2 weeks ago. 



My essential bus will be the following - uAvionix AV30 (basic EFIS), GPS Navigator, and the engine monitor. 



Battery bus will be the two Lightspeed ignitions - switch, no breaker, just fuse links.



Keeping the Avionics bus - bad habits are hard to break. 



Because the Avidyne IFD has dual power inputs that are diode or'd, I'll feed one side from the Avionics and the other from the Essential bus. Other items don't so I'll put two schottky diodes in to prevent backfeeding. Or, what 20A schottky diode is recommended that can support my whole essential bus? Can't see where I can buy the AEC9001-1.



One ignition will have a 3 position switch - middle position will go to a small standby battery for power in case the world is coming undone. Totally isolated then except for that switch.



Normal flight - ESS bus off, master on. Electrical stuff goes weird - ESS on and Master off. Engine quits, IGN1 to middle position.



Charlie, What's your brown-out booster look like? 



Getting real close! Thanks!



Andy

nuckolls.bob(at)aeroelect
Guest

Posted: Mon May 09, 2022 3:54 am Post subject: Too many Circuit breakers....

At 02:54 PM 5/7/2022, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "andymeyer" <meyerkc135(at)gmail.com>



 Alright - looks like I might have some breakers to sell.

 What's an ideal fuse block model for the ATC fuses. Any good brand or model suggested? I'm scared of some of the stuff I see.



 



 nuckolls.bob(at)aeroelect wrote:

 > 

 >  

 >  

 > > The only thing on that list that I'd put on a breaker is the alternator field supply.

 > 

 >    But even this is not necessary if you have something

 >    other than crowbar ov management.

 > 



 Do I read this as: Since I've got the LR3D I don't need a breaker for the alternator even though BandC calls for one? Just put a fuse where they call for breakers? 	


   NO!  The B&C products FEATURE crowbar ov

   management . . . a system that expects

   to open the alternator field feeder

   during an ov condition. That protection

   CAN be a fuse but then you have no

   convenient way to reset in case of a rare

   but not zero probability of a nuisance

   trip. 



   This is why you see a breaker in the field

   supply feeder in all of the z-figures

   when a B&C alternator controller -OR-

   crowbar ov module is incorporated. This

   is recommended whether or not you choose

   to use fuse blocks.



 

  	  Quote: 	
		  My ignitions - 2 Lightspeeds - What's the best protection for the wires running from the panel to the back seat? I still need switches to turn them on or off, might I be better off with a W31 Breaker switch and that be it, or is the complexity of the W31 a risk? Part of me would like to be able to reset it if the engine goes quiet and I'm out of other options. Though 2 dying at once seems highly improbable. 	


   You have pretty much answered your own

   question. Review architecture and series

   of events that ended up trashing a nice

   LanceAir IVP a few years ago.



  http://aeroelectric.com/Reference_Docs/Accidents/N811HB_Feb2008_LA-IVp/ 



   My post of last night suggests reviewing

   an accident that was probably a result

   of poor electrical system architecture.



   Being able to reset blown protection in flight

   is WAayyy down on the list of priorities

   for pilots. Electro-whizzies go belly-up

   for many MORE reasons than a fault that opens

   a breaker. When a breaker does open, it indicates

   (1) a DESIGN problem (see youtube narrative on

   P51 replica crash) or (2) something is broke (and

   resetting the breaker is not going to fix it).



   Judicious exercise of failure mode effects analysis

   leads to failure tolerant selection of appliances

   and architecture powering those appliances thus

   mitigating design issues. This leaves only

   a gross overload events for which a re-setable

   feeder protection is of no value.



   Besides, if something stops working in flight,

   one is well advised to get on the ground before

   trading your pilot's hat for a mechanic's hat.



 

  	  Quote: 	
		  Radio Master (Currently a W31 breaker switch) - people seem to be moving away from avionics masters - is that really the best case these days? 	


   I was at Cessna circa 1965 when the avionics

   master was conceived . . . for the wrong reasons.

   Nonetheless, the concept flourished in virtually

   all GA aircraft in spite of no demonstrable risks

   to avionics and in spite of environmental qualification

   testing requiring that avionics be immune to

   normal and expected electrical stresses in

   the ship's power generation system.



  	  Quote: 	
		  Let the Garmin and Avidyne stuff suffer the brown-out during start and reboot? Or go around twisting knobs off and on? I'd like to be able to get rid of as much load during start. Normally, only things I have is LED Nav lights and the engine monitor. (Engine monitor only needs ~4 volts to run) 	


   Load shedding for the purposes of relieving

   stress on battery during start is a thing of

   yesteryear. A panel full of radios in a 1965

   C172 was a significant load on a soggy

   battery suffering the abuse of starter motor

   adapted from farm tractors.



   Today's avionics draw a small fraction of that

   energy. Batteries are more robust. Starters

   get the fan fired up much faster. Load shedding

   for start assist is an idea that has pretty

   much evaporated.



 

   Bob . . .



   Un impeachable logic: George Carlin asked, "If black boxes

   survive crashes, why don't they make the whole airplane

   out of that stuff?"

Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Mon May 09, 2022 5:37 am Post subject: Too many Circuit breakers....

snipped

[quote] [quote]Let the Garmin and Avidyne stuff suffer the brown-out during start and reboot? Or go around twisting knobs off and on? I'd like to be able to get rid of as much load during start

_________________
Charlie

nuckolls.bob(at)aeroelect
Guest

Posted: Mon May 09, 2022 8:00 am Post subject: Too many Circuit breakers....

 	  Quote: 	
		  Because the Avidyne IFD has dual power inputs that are diode or'd, I'll feed one side from the Avionics and the other from the Essential bus. Other items don't so I'll put two schottky diodes in to prevent backfeeding. 	


   Are you exploiting any of the z-figures? Two

   diodes should never be needed.



   It would be exceedingly useful if you would sketch

   your distribution plan and share it on the

   List. It's that ol' "Picture worth 10,000

   words thingy".



  	  Quote: 	
		   Or, what 20A schottky diode is recommended that can support my whole essential bus? Can't see where I can buy the AEC9001-1. 	


   Essential or endurance bus? And do you KNOW

   what the total load on that bus is?  



   The 9001 was discontinued because it was a bad

   idea. Over the years we got wrapped tightly around

   the 'save energy' axle  . . . and Schottky

   diodes planted the seed of some poor decisions.



   For the past 25 years or so, I've showcased

   the bridge rectifier assembly as a ready-off-the-

   shelf solution to diode isolation in our

   distribution systems. Inexpensive, dozens

   of sources, easy wiring (fast-ons), easy

   mounting (one screw in the middle), zero

   risk for shorting (no insulators required).



   Down side? A few tenths of a volt greater

   voltage drop. Okay, what are the OBSERVABLE

   benefits for eliminating that extra drop?



   ZERO



   So what is the return on investment for fiddling

   with that gold-plated solution to lowering

   voltage drop?  I suggest its on a par with

   going lithium just to save weight. There are

   no benefits to either (1) saving of a few tenths

   of a volt -or- (2) a few pounds in an airplane.



   Both are more expensive and fussier to

   implement/maintain with performance improvements

   difficult to measure and impossible to demonstrate.



 

  	  Quote: 	
		  One ignition will have a 3 position switch - middle position will go to a small standby

 battery for power in case the world is coming undone. 	


   Do you not plan to maintain the ship's battery

   in an airworthy condition? I.e. periodic cap-checks

   to maintain design goals? If not, then what is

   your game plan for maintaining a SECOND battery

   in an airworthy condition?



   Over the years, we've studied the occasional dark-n-stormy-

   night narrative from one of aviation journals. A common

   characteristic of those stories is that they seldom,

   if ever, describe shortcomings in either selection of

   hardware or preventative maintenance that would have

   kept that event from occurring. They ALWAYS conjure

   up a litany of advice and cautions for how to deal

   with that situation should it happen AGAIN to you!



   Failure tolerant design and maintenance strives to

   prevent any failure from becoming a dark-n-stormy

   night story over beers . . . or an obituary.

   



 

   Bob . . .



   Un impeachable logic: George Carlin asked, "If black boxes

   survive crashes, why don't they make the whole airplane

   out of that stuff?"

nuckolls.bob(at)aeroelect
Guest

Posted: Mon May 09, 2022 10:08 am Post subject: Too many Circuit breakers....

 	  Quote: 	
		   



  These days, with EFIS equipment, it's more about inconvenience than load shedding. Some EFIS products take 2-3 minutes to boot and self-calibrate,Â and I've seen them 'lock up' during engine start. If they reboot due to brownout at engine start, that 3 minutes feels like half the planned flight time. Â  If they lock up, then you typically have to power down the whole panel to get them to restart.Â 	


    Brown-out mitigation is indicated for sure



 



 

   Bob . . .



   Un impeachable logic: George Carlin asked, "If black boxes

   survive crashes, why don't they make the whole airplane

   out of that stuff?"

nuckolls.bob(at)aeroelect
Guest

Posted: Mon May 09, 2022 10:11 am Post subject: Too many Circuit breakers....

 	  Quote: 	
		  These days, with EFIS equipment, it's more about inconvenience than load shedding. Some EFIS products take 2-3 minutes to boot and self-calibrate,Â and I've seen them 'lock up' during engine start. If they reboot due to brownout at engine start, that 3 minutes feels like half the planned flight time. Â  If they lock up, then you typically have to power down the whole panel to get them to restart.Â 	


   If I were qualifying an electro-whizzy for TC

   aircraft, DO160 power input tests have to demonstrate

   timely fault free recovery under various

   power input conditions. I would not be able to

   put such devices on a TC aircraft.



 



 

   Bob . . .



   Un impeachable logic: George Carlin asked, "If black boxes

   survive crashes, why don't they make the whole airplane

   out of that stuff?"

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