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farmrjohn

Joined: 31 Dec 2018
Posts: 54

Posted: Tue Nov 24, 2020 8:33 am Post subject: Switch Question

My master switch is specified as an AN 3023-2.  I have been unable to find any documentation on just what that is, other than some type of DPST switch.  Is there a source for decoding the AN switch specifications?

user9253

Joined: 28 Mar 2008
Posts: 1908
Location: Riley TWP Michigan

Posted: Tue Nov 24, 2020 1:29 pm Post subject: Re: Switch Question

That switch is available for $30 at Univair

https://www.univair.com/electrical-lighting/view-all/an3023-2-piper-switch/

Any snap action switch will work.  The master contactor draws less than an amp.

Be sure to put a diode across the contactor coil to protect the switch from arcing.

The banded end of the diode connects to positive.

_________________
Joe Gores

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Nov 24, 2020 1:46 pm Post subject: Switch Question

At 10:33 AM 11/24/2020, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "farmrjohn" <faithvineyard(at)yahoo.com>



 My master switch is specified as an AN 3023-2.  I have been unable to find any documentation on just what that is, other than some type of DPST switch.  Is there a source for decoding the AN switch specifications?

   	


  That is a vintage switch dating back to the 40's or earlier.

  It's reminiscent of the master switch in a Piper TriPacer

  I took dual in wwwaayyy back when. BEEFY switch, no battery

  master relay. 



  They're still available as you can see here . . .

 

  https://tinyurl.com/y57x62bp



  What's your application?



 

 

   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: Tue Nov 24, 2020 4:07 pm Post subject: Switch Question

At 03:41 PM 11/24/2020, you wrote:

  	  Quote: 	
		  At 10:33 AM 11/24/2020, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "farmrjohn" <faithvineyard(at)yahoo.com>



 My master switch is specified as an AN 3023-2.  I have been unable to find any documentation on just what that is, other than some type of DPST switch.  Is there a source for decoding the AN switch specifications?

   	


  That is a vintage switch dating back to the 40's or earlier.

  It's reminiscent of the master switch in a Piper TriPacer

  I took dual in wwwaayyy back when. BEEFY switch, no battery

  master relay. 



  They're still available as you can see here . . .



  https://tinyurl.com/y57x62bp



  What's your application?



 	


   P.S. I have confirmed that this switch was used on

   Univair (ERCO) aircraft as the primary current

   carrying device for ship's power. This IS a high

   current switch . . . probably rated at 30A or more.



   If that's how it's used in your application, suggest

   you add a battery master contactor thus allowing

   substitution of a friendlier toggle switch. 



 

 

   Bob . . .



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

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

   out of that stuff?"

farmrjohn

Joined: 31 Dec 2018
Posts: 54

Posted: Tue Nov 24, 2020 7:47 pm Post subject: Re: Switch Question

My airplane is an Alon Aircoupe that Univair now has the TCSD for.  It does not have a battery master contactor, and the STC available to add one does not include the Alons due to a change in the battery box and location.  I am working with my A&P/IA on a possible field approval, along with a lithium battery installation.  I was curious about the AN switch and what its characteristics are.

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Nov 25, 2020 8:05 am Post subject: Switch Question

At 09:47 PM 11/24/2020, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "farmrjohn" <faithvineyard(at)yahoo.com>



 My airplane is an Alon Aircoupe that Univair now has the TCSD for.  It does not have a battery master contactor, and the STC available to add one does not include the Alons due to a change in the battery box and location.  I am working with my A&P/IA on a possible field approval, along with a lithium battery installation.  I was curious about the AN switch and what its characteristics are.

 	


   I used to have some Cuttler-Hammer data from that

   era but I'm unable to access it. But we can be

   sure that this switch is not off your grandpa's

   yard tractor. It's a beefy device used on many

   small aircraft of the era as THE battery master.



   Getting a field approval for battery and contactor

   upgrade shouldn't be a big deal. It's a rudimentary

   but significant performance upgrade.



 

 

   Bob . . .



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

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

   out of that stuff?"

farmrjohn

Joined: 31 Dec 2018
Posts: 54

Posted: Wed Nov 25, 2020 7:25 pm Post subject: Re: Switch Question

 	  nuckolls.bob(at)aeroelect wrote: 	
		  



   Getting a field approval for battery and contactor

   upgrade shouldn't be a big deal. It's a rudimentary

   but significant performance upgrade.



 

 

   Bob . . .



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

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

   out of that stuff?" 	




Totally agree, it's just a matter of finding someone at the local FSDO that has the same point of view.  John

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Nov 27, 2020 8:33 am Post subject: Switch Question

 	  Quote: 	
		  

 Totally agree, it's just a matter of finding someone at the local FSDO that has the same point of view.  John

 	


   Are there any Type Clubs for your airplane?

   It might be possible to got a copy of an

   already approved 337 for doing this job.

   Using that as foundation for your new

   endeavor will go a long way toward assuaging

   timidity on the part of individuals with

   little or no familiarity with vintage aircraft.



   Use the battery contactor installation on any later

   version of that aircraft to create a narrative/

   photo essay on a proposed modification to your

   airplane.



   Lacking that, find an STC for ANY such modification

   to a vintage aircraft. Use it as a pattern to

   create your own documentation. 



   Don't ASK 'em how to do it, TELL them how you're

   going to do it on a foundation of prior

   art.



   When and if you're successful, preserve copies

   of your approved paperwork and share with interested

   owners. You can become a repository for a

   knowledge-nugget of tribal knowledge.



 

   Bob . . .



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

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

   out of that stuff?"

farmrjohn

Joined: 31 Dec 2018
Posts: 54

Posted: Thu Dec 14, 2023 4:14 pm Post subject: Re: Switch Question

Reviving an old thread, when the original generator was swapped out for an alternator they utilized only one pole of the two pole switch to connect the batter to the bus, leaving the other side unused.  Would it be possible to utilize the unused poles to control a master contractor leaving the heavy wiring from the batter to the switch in place?  That way when the switch was closed it would energize the contractor and allow the connection to the bus, and provide a backup method of disconnecting the battery should the contractor fail closed for any reason.  This is in anticipation of pursuing a field approval for a contacor.  Thanks, John



 	  nuckolls.bob(at)aeroelect wrote: 	
		  At 03:41 PM 11/24/2020, you wrote:

  	  Quote: 	
		  At 10:33 AM 11/24/2020, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "farmrjohn" <faithvineyard>



 My master switch is specified as an AN 3023-2.  I have been unable to find any documentation on just what that is, other than some type of DPST switch.  Is there a source for decoding the AN switch specifications?

   	


  That is a vintage switch dating back to the 40's or earlier.

  It's reminiscent of the master switch in a Piper TriPacer

  I took dual in wwwaayyy back when. BEEFY switch, no battery

  master relay. 



  They're still available as you can see here . . .



  https://tinyurl.com/y57x62bp



  What's your application?



 	


   P.S. I have confirmed that this switch was used on

   Univair (ERCO) aircraft as the primary current

   carrying device for ship's power. This IS a high

   current switch . . . probably rated at 30A or more.



   If that's how it's used in your application, suggest

   you add a battery master contactor thus allowing

   substitution of a friendlier toggle switch. 



 

 

   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: 1908
Location: Riley TWP Michigan

Posted: Thu Dec 14, 2023 4:29 pm Post subject: Re: Switch Question

Contactors are unlikely to fail closed.  I would remove existing cables 

between the battery and main power bus.  Then install a contactor 

between the battery and bus.

_________________
Joe Gores

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Dec 15, 2023 9:05 am Post subject: Switch Question

At 06:14 PM 12/14/2023, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "farmrjohn" <faithvineyard(at)yahoo.com>



 Reviving an old thread, when the original generator was swapped out

 for an alternator they utilizedg only one pole of the two pole

 switch to connect the batter to the bus, leaving the other side unused.

 Would it be possible to utilize the unused poles to control a master

 contractor leaving the heavy wiring from the batter to the switch

 in place?  That way when the switch was closed it would energize the

 contractor and allow the connection to the bus, and provide a backup

 method of disconnecting the battery should the contractor fail

 closed for any reason.  This is in anticipation of pursuing a

 field approval for a contacor.  Thanks, John 	


  Have you engaged an IA to assist in fabricating

  an Form 337 likely to be summarily approved?



  Find the maintenance manual drawings for the first

  airplane of the series that replaced the

  battery switch with a contactor. This is 'approved

  data'. Duplicate the architecture of that

  drawing in support of your 337 goes along way

  to getting it approved.



  Your risk of contactor-failure-by-sticking-

  closed is more remote now than it was 70

  years ago. I've never heard of a 'back up

  battery disconnect' in any aircraft.



  Imitation is a demonstrated form of flattery . . .

  it's also a demonstrated prophylactic

  against bureaucratic disapproval. What

  airplane are we talking about? I may

  have the drawings you need in my library.



 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

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

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

user9253

Joined: 28 Mar 2008
Posts: 1908
Location: Riley TWP Michigan

Posted: Fri Dec 15, 2023 9:37 am Post subject: Re: Switch Question

His airplane is an Alon Aircoupe that Univair now has the TCSD for.

_________________
Joe Gores

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Dec 15, 2023 10:31 am Post subject: Switch Question

At 11:37 AM 12/15/2023, you wrote:

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



 His airplane is an Alon Aircoupe that Univair now has the TCSD for.



 --------

 Joe Gores

 	


   Okay, thanks Joe.



   It' been 20 years since I was last involved in any

   'certifiable' field work on a TC aircraft so I dug

   back into some old files.



   There were individuals certificated by the FAA

   to accomplish various tasks. There are also

   various levels of documentation needed to support

   the project implementation.



   As I recall, there are 'repairs' and 'alterations.'

   They're also divided into 'major' and 'minor'

   classifications. Minor alternations are those

   that do not change performance of the airplane.

   This generally defined as less than 1 pound

   difference in empty weight of the aircraft

   (hence no change to w/b). No changes needed

   to the pilot's operating handbook. No alterations

   to any structural component of the airframe

   (like holes thru a spar).



   The proposed swap from manual battery switch

   to battery contactor could certainly fall in

   the minor category (unless you want to drill

   the spar carrythru to mount the contactor!)



   Check with your local FAA certified talent

   but waaayyy back when, I believe such a change

   could be accomplished with a log book entry

   by an appropriately qualified practitioner.

   No 337 necessary.



 

 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

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

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

farmrjohn

Joined: 31 Dec 2018
Posts: 54

Posted: Fri Dec 15, 2023 12:49 pm Post subject: Re: Switch Question

Here is the original wiring diagram from the Alon maintenance manual (if I successfully added the attachment).  The wiring has changed with the addition of an alternator in place of a battery.  The circuit for field "F" on the regulator now comes via the alternator rather than the top pole of the switch as depicted.  



Looking at the current definition for minor alteration the question is does the addition of a contractor constitute a change to the basic design of the system.  My IA and myself don't think so but I'm a bit concerned looking forward to a pre-sale inspection and the buyer's inspector thinking otherwise.  A 337 field approval should eliminate any doubt in that case.  John

Aircoupe Electrical System.pdf

Description:

Download

Filename:

Aircoupe Electrical System.pdf

Filesize:

1.12 MB

Downloaded:

134 Time(s)

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Dec 15, 2023 4:03 pm Post subject: Switch Question

At 02:49 PM 12/15/2023, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "farmrjohn" <faithvineyard(at)yahoo.com>



 Here is the original wiring diagram from the Alon maintenance manual (if I successfully added the attachment).  The wiring has changed with the addition of an alternator in place of a battery.  The circuit for field "F" on the regulator now comes via the alternator rather than the top pole of the switch as depicted. 	


   That's an architecture 'cartoon' common to most

   pilot's operating handbook for light aircraft.

   Drew up lots of them at Cessna. 'Approved data'

   would be from any 'hammer-n-tongs' document.

   At Cessna, our factory wirebook drawings were

   published in the maintenance manuals.



   Aircraft of this era may not have enjoyed this

   kind of documentation. I only have first hand

   knowledge of Beech, Cessna and Lear . . .  places

   I've worked. That airplane may not ever

   have been graced with a factory battery 

   contactor installation. It just means you don't

   have an 'approved' factory document . . . doesn't

   mean the drawing you attach to your 337 would

   not be approved. An alternator swap would

   always require a 337; it changes

   weight and balance and might be need to be

   tested for adequate cooling at best angle

   of climb (depending on mood of the approving

   authority). 



   Swapping a switch for a contactor is zero

   risk and doesn't impact performance, w/b or

   operating instructions i.e. MINOR . . .

   no change of functionality.



  	  Quote: 	
		  Looking at the current definition for minor alteration the question is does the addition of a contractor constitute a change to the basic design of the system.  My IA and myself don't think so but I'm a bit concerned looking forward to a pre-sale inspection and the buyer's inspector thinking otherwise.  A 337 field approval should eliminate any doubt in that case.  John

 	
  You're asking 'hair dressers' about 'heart

   surgery'. The authority resides with the

   individual who signs off the installation.

   If uncertain, that individual should/would

   consult with the local FSDO.



   A 337 adds to the FSDO workload . . . the

   gotta file the thing. Have your IA check

   it out with them . . . THEY are the

   'surgeons'. 



 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

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

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

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