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Toggle Actuated Circuit Breakers

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longg(at)pjm.com
Guest

Posted: Thu Feb 05, 2009 5:58 am Post subject: Toggle Actuated Circuit Breakers

With respect to life cycles how do the switch type circuit breakers hold up? I am looking at the Potter & Brumfield variety.   Thanks  

   

      [quote][b]

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rparigor(at)SUFFOLK.LIB.N
Guest

Posted: Thu Feb 05, 2009 7:55 am Post subject: Toggle Actuated Circuit Breakers

"> With respect to life cycles how do the switch type circuit breakers hold > up? I am looking at the Potter & Brumfield variety."I can tell you from experience, if you try and loosen the screw on one without supporting the metal tab it will not last one cycle!I am not sure if it is exact switch, but Beechcraft is going through some noise to have toggle breakers all replaced on I think it is Barons due to a failure. Not sure if it was an open or closed failure. (There is enough stuff going on in switch/breaker I could see there is a remote chance it could fail miserably and weld itself closed or make a high resistance connection and make plenty of heat)That said local AIs and A+Ps all told me reliability is good, they don't think any worst than pull able breakers, or switches that do fail from time to time.B+C is not an advocate of using them to supply power to field, said they can sometimes (more often than they feel acceptable) make a higher resistance connection than is needed for stable running alternator. Found this tid bit out after I installed one for my SD20S, but will keep that information handy if I develop a problem.Not from experience but from dissecting one and studying, probably would not be a bad idea to replace any very important toggle/breakers at perhaps major time or 15 years?? Grease will go away and the plastic arm to reset looks to me it could be a failure point. I think if it is closed will probably be pretty reliable, as far as from a mechanical standpoint goes. Resetting imposes a lot more mechanical stresses than opening.See:http://www.europaowners.org/modules.php?set_albumName=album258&op=modload&name=gallery&file=index&include=view_album.phpBreak a breaker.I am using perhaps a dozen or so on our Europa project, primarily from a space savings point of view. I didn't weigh difference between a Klixon pull able breaker and a switch, but expect the later is probably lighter (a bank or 9 is pretty heavy).I forget exacts, but if a P+B toggle/breaker is good for 9 or 12K cycles, supposedly a Klixon pull able breaker used as a switch (that it is not precisely designed for) is good for 3 or 4K cycles. If I am off on the number of cycles, it is not by much but it is what was told me. You can look at a engineering sheet if you are really interested, failure from lack of use and mechanical related age induced stresses are much more likely though.Ron Parigoris   [quote][b]

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longg(at)pjm.com
Guest

Posted: Fri Feb 06, 2009 10:50 am Post subject: Toggle Actuated Circuit Breakers

Thanks Ron,  

   

That’s what I was looking for. So if I really use it as a switch and a breaker, the term life is good.  

     

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of rparigor(at)SUFFOLK.LIB.NY.US

 Sent: Thursday, February 05, 2009 10:53 AM

 To: AeroelectricList

 Subject: Re: Toggle Actuated Circuit Breakers  

  

   

"> With respect to life cycles how do the switch type circuit breakers hold 

 > up? I am looking at the Potter & Brumfield variety."

 

 I can tell you from experience, if you try and loosen the screw on one without supporting the metal tab it will not last one cycle!

 

 I am not sure if it is exact switch, but Beechcraft is going through some noise to have toggle breakers all replaced on I think it is Barons due to a failure. Not sure if it was an open or closed failure. (There is enough stuff going on in switch/breaker I could see there is a remote chance it could fail miserably and weld itself closed or make a high resistance connection and make plenty of heat)

 

 That said local AIs and A+Ps all told me reliability is good, they don't think any worst than pull able breakers, or switches that do fail from time to time.

 

 B+C is not an advocate of using them to supply power to field, said they can sometimes (more often than they feel acceptable) make a higher resistance connection than is needed for stable running alternator. Found this tid bit out after I installed one for my SD20S, but will keep that information handy if I develop a problem.

 

 Not from experience but from dissecting one and studying, probably would not be a bad idea to replace any very important toggle/breakers at perhaps major time or 15 years?? Grease will go away and the plastic arm to reset looks to me it could be a failure point. 

 

 I think if it is closed will probably be pretty reliable, as far as from a mechanical standpoint goes. Resetting imposes a lot more mechanical stresses than opening.

 

 See:

 http://www.europaowners.org/modules.php?set_albumName=album258&op=modload&name=gallery&file=index&include=view_album.php

 

 Break a breaker.

 

 I am using perhaps a dozen or so on our Europa project, primarily from a space savings point of view. 

 

 I didn't weigh difference between a Klixon pull able breaker and a switch, but expect the later is probably lighter (a bank or 9 is pretty heavy).

 

 I forget exacts, but if a P+B toggle/breaker is good for 9 or 12K cycles, supposedly a Klixon pull able breaker used as a switch (that it is not precisely designed for) is good for 3 or 4K cycles. If I am off on the number of cycles, it is not by much but it is what was told me. You can look at a engineering sheet if you are really interested, failure from lack of use and mechanical related age induced stresses are much more likely though.

 

 Ron Parigoris   	  Quote: 	
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      [quote][b]

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nuckolls.bob(at)aeroelect
Guest

Posted: Sat Feb 07, 2009 7:02 am Post subject: Toggle Actuated Circuit Breakers

At 07:55 AM 2/5/2009, you wrote:



  	  Quote: 	
		  With respect to life cycles how do the switch type circuit breakers hold up? I am looking at the Potter & Brumfield variety. 



 

 Thanks 	


   Go to the Matronics.com archives search and review

   the 59 or so messages on AeroElectric-List that

   mention "W31".



   These are not the best breaker/switch in the world

   nor are they the worst. Since we're building FAILURE

   TOLERANT airplanes, use of these devices to meet

   your design goals is not a decision fraught with

   evil or risk.



 

        Bob . . .



        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------



     [quote][b]

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longg(at)pjm.com
Guest

Posted: Mon Feb 09, 2009 6:49 am Post subject: Toggle Actuated Circuit Breakers

Thanks Bob,  

   

 	  Quote: 	
		  >>>>>   

   The big band-aid is to install a separate high  
	


   current relay to the battery through a LARGE  

   in line fuse . . . probably 30A. Run 14AWG wire  

   from the relay up to the panel mounted 5A breaker.  

   Continue on with what-ever wire is called out  

   to continue on to the ignition system. Now you  

   need switches to control right and left ignition  

   system relays at the battery. See:  

   

http://aeroelectric.com/Pictures/Schematics/Battery_Feed_for_Ignition.pdf  

   

   This approach could be blessed in a TC aircraft  

   as providing circuit protection commensurate with  

   wire sizes AND making the system max-cold when  

   the switches are OFF.  

   

   

        Bob . . .  

<<<<<<<<   

   

   

To eliminate parts count I am planning to use two of the switched circuit breakers to attach my dual plasma III modules. I will plan to run 14 AWG to the breaker/switches. Distance (2.5’) and weight are not a factor for two such wires in my setup.   

   

In your above sketch are you depicting the two 30A ATC fuse be of the in-line type?  

What size wire do you suggest between the batt bus and the ATC? Currently I am #10 from the contactor to the batt buss – assume same?  

   

Based on the estimated number of life cycles for the P & B switched breakers, I am fine with that risk. Changing them out every 4-5 years would be more than sufficient in my case.  

   

Thanks,  

Glenn  

   

   

   

   

   

       

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Robert L. Nuckolls, III

 Sent: Saturday, February 07, 2009 10:01 AM

 To: aeroelectric-list(at)matronics.com

 Subject: Re: Toggle Actuated Circuit Breakers   

  

  

   

At 07:55 AM 2/5/2009, you wrote:

 

 

   With respect to life cycles how do the switch type circuit breakers hold up? I am looking at the Potter & Brumfield variety.   



 

   Thanks  



   Go to the Matronics.com archives search and review

   the 59 or so messages on AeroElectric-List that

   mention "W31".

 

   These are not the best breaker/switch in the world

   nor are they the worst. Since we're building FAILURE

   TOLERANT airplanes, use of these devices to meet

   your design goals is not a decision fraught with

   evil or risk.

 

 

   

       Bob . . .

 

        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------   	  Quote: 	
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      [quote][b]

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