Matronics Email Lists :: View topic - BnC Continuous Duty Contactor 12 v

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

BnC Continuous Duty Contactor 12 v

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

jskiba(at)icosa.net
Guest

Posted: Sun Jul 27, 2008 1:52 pm Post subject: BnC Continuous Duty Contactor 12 v

Does anyone know how much current the Continuous Duty Contactor 12 v listed

at the B n c Website can handle ?

I tried looking for some kind of data sheet but could not find one...



Does it handle better than 130 amps ?

May 90 ?



Help anyone please.



The specs they do list are:

This contactor is suited for most applications in amateur built airplanes

calling for continuous duty operation including (1) battery master contactor

(2) ground power contactor (3)alternator b-lead overvoltage protection (4)

dual alternator system crossfeed contactor [order S701-2] and (4)

extend/retract control in hydraulic landing gear systems. Supplied with

spike suppression diode and battery terminal jumper already installed. Coil

resistance is 15 ohms. Contactor Weight is 13 ounces

This contactor terminals will use a .31 and #10 ring terminals.

rshannon

Joined: 05 Sep 2007
Posts: 62

Posted: Sun Jul 27, 2008 4:35 pm Post subject: BnC Continuous Duty Contactor 12 v

Jeffrey,



I don't know the max. continuous rating, but I'm sure it's well in excess of 100A, way more than you would ever need in any usual homebuilt airplane. Of course, intermittently, it will handle a lot more than that, including full starter motor loads. Why not just give B&C a call tomorrow and ask them.

 

Ron

On Sun, Jul 27, 2008 at 2:46 PM, Jeffrey W. Skiba <jskiba(at)icosa.net (jskiba(at)icosa.net)> wrote:

[quote] --> AeroElectric-List message posted by: "Jeffrey W. Skiba" <jskiba(at)icosa.net (jskiba(at)icosa.net)>

 

 Does anyone know how much current the Continuous Duty Contactor 12 v listed

 at the B n c Website can handle ?

 [b]

nuckolls.bob(at)cox.net
Guest

Posted: Sun Jul 27, 2008 6:29 pm Post subject: BnC Continuous Duty Contactor 12 v

At 04:46 PM 7/27/2008 -0500, you wrote:

 	  Quote: 	
		  



Does anyone know how much current the Continuous Duty Contactor 12 v listed

at the B n c Website can handle ?


	




 	  Quote: 	
		  I tried looking for some kind of data sheet but could not find one...



Does it handle better than 130 amps ?

May 90 ?


	




See:



http://aeroelectric.com/Mfgr_Data/Contactors/Stancor-WhiteRogers/Stancor_70-Series.pdf



The S701-1 contactor is a Stancor 70-902. It's rated for

80 amps continuous.  But like all switches, relays and

contactors, the ratings assume that you're going to SWITCH

those loads. In the case of a battery conactor, loads seldom

exceed tens of amps when the battery master is turned on.

By the time the starter is engaged, the battery contactor

is closed and stable. An alrady closed switch will carry

several times its rated current for short periods of time

(like cranking an engine) without serious degradation of

service life.



How are you using it that its ratings are a concern?



  Bob . . .

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

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

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

jskiba(at)icosa.net
Guest

Posted: Mon Jul 28, 2008 4:39 am Post subject: BnC Continuous Duty Contactor 12 v

See:



http://aeroelectric.com/Mfgr_Data/Contactors/Stancor-WhiteRogers/Stancor_70-

Series.pdf



The S701-1 contactor is a Stancor 70-902. It's rated for

80 amps continuous.  But like all switches, relays and

contactors, the ratings assume that you're going to SWITCH

those loads. In the case of a battery conactor, loads seldom

exceed tens of amps when the battery master is turned on.

By the time the starter is engaged, the battery contactor

is closed and stable. An alrady closed switch will carry

several times its rated current for short periods of time

(like cranking an engine) without serious degradation of

service life.



How are you using it that its ratings are a concern?

I am using it as a battery contactor but with a Very High out alternator,

200amps ..... So I am thinking I need to find a bigger contactor ?  or my

other thought - guess was maybe to run TWO Stancor 70-902 contactors in

parallel ? with the extra wires also... but concern here is that something I

haven't thought of will smoke something if both are not closed ?



Maybe I am overlooking a simple cheaper solution....

Eric M. Jones

Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts

Posted: Mon Jul 28, 2008 6:33 am Post subject: Re: BnC Continuous Duty Contactor 12 v

I have railed against these Type-70 contactors for years. But they are almost obsolete. Most electronics distributors have dropped them from their lines. 



Problems--



1) Low Temperature rating. Only 122F max. You could land at Furnace Creek in Death Valley in May and take off in October. Maybe. This is primarily due to the Nylon innards. This is a drop-dead reason to avoid the part.



2) Not sealed. Not dust proof, or fuel proof. 



3) Low interrupt capacity. 



4) High hold current---16 ohm coil. Almost one amp.



5) Low hold force. The specifications call for specific orientation. 2G rating?



6) Wildly wrong for B&C to use coil suppression diodes on these. This causes short lifetimes on the B&C parts. 



7) Not designed to open against voltages above 36 volts. (So forget the B-lead applications)



See: www.stancor.com



There are better ways to go. Omron's line of automotive contactors (CHEAP) and Kilovac's EV200 series, Blue Sea 9012, Gigavac's GX-11. Expensive but preferred. 



Can you use them? Sure. Should you use them?....not on my bird, Bubela.



Better yet, avoid all contactors and use manual switches if you can. 



"Facts do not cease to exist because they are ignored."   

          ---Aldous Huxley

_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net

Michael Wynn

Joined: 10 Jan 2006
Posts: 148
Location: San Ramon, CA

Posted: Mon Jul 28, 2008 3:37 pm Post subject: BnC Continuous Duty Contactor 12 v

The below is entirely new to me.  Could someone with more experience  and knowledge than me (that would be almost anyone, but especially Mr. Nuckolls)  comment on it?

  

 Regards,

  

 Michael Wynn

 RV 8 FWF

 San Ramon, CA

  

  In a message dated 7/28/2008 7:39:15 A.M. Pacific Daylight Time,  emjones(at)charter.net writes:

  	  Quote: 	
		  railed    against these Type-70 contactors for years. But they are almost obsolete. Most    electronics distributors have dropped them from their lines.    



Problems--



1) Low Temperature rating. Only 122F max. You could    land at Furnace Creek in Death Valley in May and take off in October. Maybe.    This is primarily due to the Nylon innards. This is a drop-dead reason to    avoid the part.



2) Not sealed. Not dust proof, or fuel proof.    



3) Low interrupt capacity. 



4) High hold current---16 ohm coil.    Almost one amp.



5) Low hold force. The specifications call for specific    orientation. 2G rating?



6) Wildly wrong for B&C to use coil    suppression diodes on these. This causes short lifetimes on the B&C parts.    



7) Not designed to open against voltages above 36 volts. (So forget    the B-lead applications)



See: www.stancor.com



There are better    ways to go. Omron's line of automotive contactors (CHEAP) and Kilovac's EV200    series, Blue Sea 9012, Gigavac's GX-11. Expensive but preferred. 



Can    you use them? Sure. Should you use them?....not on my bird,    Bubela.



Better yet, avoid all contactors and use manual switches if you    can. 



"Facts do not cease to exist because they are    ignored."   

          ---Aldous    Huxley

	




Get fantasy football with free live scoring. Sign up for FanHouse Fantasy Football today.

  [quote][b]

_________________
Michael Wynn
RV 8
San Ramon, CA

jskiba(at)icosa.net
Guest

Posted: Mon Jul 28, 2008 7:43 pm Post subject: BnC Continuous Duty Contactor 12 v

I looked at some of those below and found this in the process:

http://www.trombetta.com/cm/pdfs/defender-family.pdf

Anybody use one of these?

Looks like they can be had for fairly cheap and have some type of TVS

(Transient Volt Suppression) built in!

Looks like it's a little heavier than some of the more expensive ones, so I

guess that's the trade off for cost.



Thoughts?



Jeff.




<emjones(at)charter.net>



I have railed against these Type-70 contactors for years. But they are

almost obsolete. Most electronics distributors have dropped them from their

lines. 



Problems--



1) Low Temperature rating. Only 122F max. You could land at Furnace Creek in

Death Valley in May and take off in October. Maybe. This is primarily due to

the Nylon innards. This is a drop-dead reason to avoid the part.



2) Not sealed. Not dust proof, or fuel proof. 



3) Low interrupt capacity. 



4) High hold current---16 ohm coil. Almost one amp.



5) Low hold force. The specifications call for specific orientation. 2G

rating?



6) Wildly wrong for B&C to use coil suppression diodes on these. This causes

short lifetimes on the B&C parts. 



7) Not designed to open against voltages above 36 volts. (So forget the

B-lead applications)



See: www.stancor.com



There are better ways to go. Omron's line of automotive contactors (CHEAP)

and Kilovac's EV200 series, Blue Sea 9012, Gigavac's GX-11. Expensive but

preferred. 



Can you use them? Sure. Should you use them?....not on my bird, Bubela.



Better yet, avoid all contactors and use manual switches if you can.

klehman(at)albedo.net
Guest

Posted: Tue Jul 29, 2008 4:00 am Post subject: BnC Continuous Duty Contactor 12 v

The Trombetta mentioned below looks like a type 70 in an expensive 

package to me.



In a nutshell my thoughts on the type 70 criticism are:

some of it is true, most of it is irrelevant.



Type 70 contactors are widely available, affordable, and no real risk 

with aeroelectric architecture except perhaps for a B lead overvoltage 

interupter with an IR alternator. Sure I might have to replace one of 

mine in my lifetime.  I think I have a spare $14. unit in stock from the 

local hardware store but I'd also expect to find one at most any airport 

if needed.



However if Eric or anyone wanted to suggest a particular "cheap" or 

value priced Omron part number or series, I would check it out for cost 

effectiveness and reasonable availability and interchangeability.



Lots of discussion in the archives Michael but I would not hesitate to 

use the type 70's in a new design for the time being. Better stuff is 

available at a price but I haven't seen anything that has a cost and 

availability of interest to me yet.



Ken

Jeffrey W. Skiba wrote:

 	  Quote: 	
		   

 

 I looked at some of those below and found this in the process:

 http://www.trombetta.com/cm/pdfs/defender-family.pdf

 

 

 Anybody use one of these?

 Looks like they can be had for fairly cheap and have some type of TVS

 (Transient Volt Suppression) built in!

 Looks like it's a little heavier than some of the more expensive ones, so I

 guess that's the trade off for cost.

 

 Thoughts?

 

 Jeff.

 

 

 <emjones(at)charter.net>

 

 I have railed against these Type-70 contactors for years. But they are

 almost obsolete. Most electronics distributors have dropped them from their

 lines. 

 

 Problems--

 

 1) Low Temperature rating. Only 122F max. You could land at Furnace Creek in

 Death Valley in May and take off in October. Maybe. This is primarily due to

 the Nylon innards. This is a drop-dead reason to avoid the part.

 

 2) Not sealed. Not dust proof, or fuel proof. 

 

 3) Low interrupt capacity. 

 

 4) High hold current---16 ohm coil. Almost one amp.

 

 5) Low hold force. The specifications call for specific orientation. 2G

 rating?

 

 6) Wildly wrong for B&C to use coil suppression diodes on these. This causes

 short lifetimes on the B&C parts. 

 

 7) Not designed to open against voltages above 36 volts. (So forget the

 B-lead applications)

 

 See: www.stancor.com

 

 There are better ways to go. Omron's line of automotive contactors (CHEAP)

 and Kilovac's EV200 series, Blue Sea 9012, Gigavac's GX-11. Expensive but

 preferred. 

 

 Can you use them? Sure. Should you use them?....not on my bird, Bubela.

 

 Better yet, avoid all contactors and use manual switches if you can.

nuckolls.bob(at)cox.net
Guest

Posted: Tue Jul 29, 2008 4:38 pm Post subject: BnC Continuous Duty Contactor 12 v

 	  Quote: 	
		  

I am using it as a battery contactor but with a Very High out alternator,

200amps ..... So I am thinking I need to find a bigger contactor ?  or my

other thought - guess was maybe to run TWO Stancor 70-902 contactors in

parallel ? with the extra wires also... but concern here is that something I

haven't thought of will smoke something if both are not closed ?


	


   No paralleling . . . it's not practical. Yes . . . you

   need a contactor rated for the task.  In the el-cheeso

   line of contactors, the Stancore 586-902 is rated for

   this service and should be a good value. See:



http://aeroelectric.com/Mfgr_Data/Contactors/Stancor-WhiteRogers/Stancor_586-Series.pdf



   You can get these for about $50 from Allied Electronics at:



http://tinyurl.com/5bxtnm



   If you're interested in "stepping up", these are equally

   suited to the task:



   Cutler-Hammer 6041H105



http://aeroelectric.com/Mfgr_Data/Contactors/Eaton_CH/6041SeriesPowerRelays.pdf



   or Tyco Killvac EV200



http://aeroelectric.com/Mfgr_Data/Contactors/Tyco_Kilovac/ev200.pdf



   Be advised that some builder's have reported noise from

   the "power saver" feature on the EV-200 that required

   filtering. Easy to do should it become necessary.



   Bob . . .



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

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

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

nuckolls.bob(at)cox.net
Guest

Posted: Tue Jul 29, 2008 5:08 pm Post subject: BnC Continuous Duty Contactor 12 v

At 07:33 AM 7/28/2008 -0700, you wrote:

 	  Quote: 	
		  



I have railed against these Type-70 contactors for years. But they are 

almost obsolete. Most electronics distributors have dropped them from 

their lines.



Problems--



1) Low Temperature rating. Only 122F max. You could land at Furnace Creek 

in Death Valley in May and take off in October. Maybe. This is primarily 

due to the Nylon innards. This is a drop-dead reason to avoid the part.



2) Not sealed. Not dust proof, or fuel proof.


	


   Neither are most of the switches, contactors, even

   alternators that have been used with great success

   for decades.



 	  Quote: 	
		  3) Low interrupt capacity.


	


   But they're never asked to interrupt anything but normal

   pre-parking currents in aircraft . . . maybe 10A? For a

   time, the TC aircraft industry attempted to use the

   intermittent duty versions of these contactors for starter

   control service and found them unsatisfactory.



   However, they have proven a good value (I didn't say lasts

   forever) in light aircraft battery contactor service.

   In other words, the 8x more expensive 6041H series mil

   spec contactors did not last even 4x as long. Given the

   exceedingly light duty cycles expected from these devices

   the way we use them (in failure tolerant systems) they

   are of good value.



 	  Quote: 	
		  4) High hold current---16 ohm coil. Almost one amp.


	


   Which is not an issue as long as the alternator

   is running . . . you have power to burn. When the

   alternator is not running, this device is turned

   off for endurance mode operations.

 	  Quote: 	
		  5) Low hold force. The specifications call for specific orientation.

    2G rating?


	


    I've tested these at over 12g.  Where do you find any recommendations

    with respect to g-loading. I can tell you that the vertical orientation

    is to reduce potential for moisture ingress due to coindensation and/or

    splash . . . as you've noted, they are not sealed. As a battery contactor,

    they are closed in all phases of flight and exceedingly difficult to

    force open with g-loads.



 	  Quote: 	
		  6) Wildly wrong for B&C to use coil suppression diodes on these. This 

causes short lifetimes on the B&C parts.


	


   I've also demonstrated that this is not true.



 	  Quote: 	
		  7) Not designed to open against voltages above 36 volts. (So forget the 

B-lead applications)


	


   True . . . and not recommended to routinely SWITCH such

   loads but will be just fine as suggested on the third page

   of:



http://aeroelectric.com/articles/Adapting_IR_Alternators_to_Aircraft.pdf



   where we will routinely switch the alternator ON and OFF at will

   without exceeding the contactors rated operating conditions.

 	  Quote: 	
		  See: www.stancor.com



There are better ways to go. Omron's line of automotive contactors (CHEAP) 

and Kilovac's EV200 series, Blue Sea 9012, Gigavac's GX-11. Expensive but 

preferred.


	


   Preference is another matter entirely . . . and when

   it comes to preferences, I'll concede to anyone's desires.

   I've even cited alternatives that include the Kilovac

   EV200. But let us not resort to generating climates of fear

   on the part of the neophyte airplane builders. The track

   record on this part for return on investment has been exemplary.



 	  Quote: 	
		  Can you use them? Sure. Should you use them?....not on my bird, Bubela.


	


   By all means sir . . .



 	  Quote: 	
		  Better yet, avoid all contactors and use manual switches if you can.


	


   This IS a stretch Eric. It's true that contactors are the

   most highly stressed devices on an airplane after generators

   and followed by alternators. It's also true that they are

   a significant maintenance item on EVERY airplane from the

   C-150 through the Hawkers. But so are tires, batteries,

   generators, etc. The artfully crafted system tolerates

   these service life limitations without placing the aircraft

   or occupants at risk. Can we really recommend that anyone

   resort to manually operated high current switches (bring

   high current conductors within reach of pilot) just to avoid

   a service-life issue on a 100-our a year airplane?

 	  Quote: 	
		  "Facts do not cease to exist because they are ignored."

           ---Aldous Huxley


	


   Absolutely! Please separate deeply held beliefs from demonstrable

   fact. I have outlined the facts  . . . which of these do you

   find to be in error?



   Bob . . .

nuckolls.bob(at)cox.net
Guest

Posted: Tue Jul 29, 2008 5:11 pm Post subject: BnC Continuous Duty Contactor 12 v

At 10:31 PM 7/28/2008 -0500, you wrote:

 	  Quote: 	
		  



I looked at some of those below and found this in the process:

http://www.trombetta.com/cm/pdfs/defender-family.pdf

Anybody use one of these?

Looks like they can be had for fairly cheap and have some type of TVS

(Transient Volt Suppression) built in!

Looks like it's a little heavier than some of the more expensive ones, so I

guess that's the trade off for cost.


	


    These should be entirely suitable for use as

    battery contactors in the OBAM aircraft.



    Bob . . .

Eric M. Jones

Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts

Posted: Wed Jul 30, 2008 6:00 am Post subject: Re: BnC Continuous Duty Contactor 12 v

Bob,



I would use a Type 70 for a puddle jumper of no particular consequence. I agree that they have been used for decades. They are not competitive anymore.  I aim for designs where "carrying a spare" is not a requirement for a part, where "better" can be had for not much money. "Better" in my world is defined as "greater capability, wider specs, longer life, higher reliability...etc." Maybe even "similar specs, lighter weight...." Not all builders care about this.

 

>Problems-- 



>1) Low Temperature rating. Only 122F max. You could land at Furnace  >Creek in Death Valley in May and take off in October. Maybe. This is >primarily due to the Nylon innards. This is a drop-dead reason to avoid >the part. 



>2) Not sealed. Not dust proof, or fuel proof. 

 

 	  Quote: 	
		  Neither are most of the switches, contactors, even 

alternators that have been used with great success 

for decades. 	




Bob, that's partially true, but Kilovacs and Gigavacs can shut off your battery whilst saturated in fuel.  They can also shut off a runaway alternator. They will last forever. They cost more. They have lower hold currents. They use bidirectional Zeners for coil suppression. Nice, huh?



>3) Low interrupt capacity. 

 

 	  Quote: 	
		  But they're never asked to interrupt anything but normal 

pre-parking currents in aircraft . . . maybe 10A? For a 

time, the TC aircraft industry attempted to use the 

intermittent duty versions of these contactors for starter 

control service and found them unsatisfactory. 	




You are referring to a specific application. I referring to general applications.



 	  Quote: 	
		  However, they have proven a good value (I didn't say lasts 

forever) in light aircraft battery contactor service. 

In other words, the 8x more expensive 6041H series mil 

spec contactors did not last even 4x as long. Given the 

exceedingly light duty cycles expected from these devices 

the way we use them (in failure tolerant systems) they 

are of good value. 	




I don't disagree. They are a good value. But Omron contactors (50A) http://tiny.cc/sXDp3 are a 3X better value and are tiny in comparison. The Type 70 is long in the tooth. As you recall this latest brushfire was sparked by troublemaker Jeff Skiba poking around to get information on higher current performance. He started this....



>4) High hold current---16 ohm coil. Almost one amp. 

 

 	  Quote: 	
		  Which is not an issue as long as the alternator 

is running . . . you have power to burn. When the 

alternator is not running, this device is turned 

off for endurance mode operations. 	




An ampere here, and ampere there...pretty soon you have real power waste. Our philosophies differ. I remember in 1960 when you could buy surplus aircraft and they'd come with full fuel tanks. Not anymore.

>5) Low hold force. The specifications call for specific orientation. 

>2G rating? 



 	  Quote: 	
		  I've tested these at over 12g. Where do you find any recommendations with respect to g-loading. I can tell you that the vertical orientation is to reduce potential for moisture ingress due to condensation and/or splash . . . as you've noted, they are not sealed. As a battery contactor, they are closed in all phases of flight and exceedingly difficult to

force open with g-loads. 	
 



You could be right on this. Type 70 specs are impossible to get on this, (and believe me I've tried). I interpret the orientation spec to be a g-load concern. But Kilovac and Gigavac and others always spec g-load. Usually 10g's.



>6) Wildly wrong for B&C to use coil suppression diodes on these. This 

>causes short lifetimes on the B&C parts. 



 	  Quote: 	
		  I've also demonstrated that this is not true. 	




As I said Bob, you are wonderfully on-the-mark about thousands of things, and only wildly wrong about only a few. 



One Hundred Dollars U.S. to your favorite charity and a jar of jalapenos to you if an agreed upon third party will test the type-70 contactor using 1N5401 Diodes vs. 18V SnapJacks for coil suppression in an agreed upon test. My winning requires you to never again espouse this bonehead notion.



 

>7) Not designed to open against voltages above 36 volts. (So forget the 

>B-lead applications) 

 

 	  Quote: 	
		  

True . . . and not recommended to routinely SWITCH such 

loads but will be just fine as suggested on the third page 

of: 



http://aeroelectric.com/articles/Adapting_IR_Alternators_to_Aircraft.pdf 



where we will routinely switch the alternator ON and OFF at will 

without exceeding the contactors rated operating conditions. 	
 

 

>There are better ways to go. Omron's line of automotive contactors

 > (CHEAP) and Kilovac's EV200 series, Blue Sea 9012, Gigavac's GX-11. >Expensive but preferred. 

 



 	  Quote: 	
		  Preference is another matter entirely . . . and when 

it comes to preferences, I'll concede to anyone's desires. 

I've even cited alternatives that include the Kilovac 

EV200. But let us not resort to generating climates of fear 

on the part of the neophyte airplane builders. The track 

record on this part for return on investment has been exemplary. 	
 



>Better yet, avoid all contactors and use manual switches if you can. 

 



 	  Quote: 	
		  This IS a stretch Eric. It's true that contactors are the 

most highly stressed devices on an airplane after generators 

and followed by alternators. It's also true that they are 

a significant maintenance item on EVERY airplane from the 

C-150 through the Hawkers. But so are tires, batteries, 

generators, etc. The artfully crafted system tolerates 

these service life limitations without placing the aircraft 

or occupants at risk. Can we really recommend that anyone 

resort to manually operated high current switches (bring 

high current conductors within reach of pilot) just to avoid 

a service-life issue on a 100-our a year airplane? 	




Bob, Stretching is a good, but not necessary thing. I recommend to my builder-friends using a Flaming River racecar battery switch to satisfy the FAA for the one-hand battery disconnect. That's what's going into my Glastar. No contactor needed. Most other contactors can go bye-bye too.



"Everything you've learned in school as 'obvious' becomes less and less obvious as you begin to study the universe. For example, there are no solids in the universe. There's not even a suggestion of a solid. There are no absolute continuums. There are no surfaces. There are no straight lines." 



-R. Buckminster Fuller

_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net

nuckolls.bob(at)cox.net
Guest

Posted: Wed Jul 30, 2008 8:37 am Post subject: BnC Continuous Duty Contactor 12 v

At 07:00 AM 7/30/2008 -0700, you wrote:

 	  Quote: 	

Bob,

I would use a Type 70 for a puddle jumper of no particular consequence. I 

agree that they have been used for decades. They are not competitive 

anymore.  I aim for designs where "carrying a spare" is not a requirement 

for a part, where "better" can be had for not much money. "Better" in my 

world is defined as "greater capability, wider specs, longer life, higher 

reliability...etc." Maybe even "similar specs, lighter weight...." Not all 

builders care about this.

   Don't now how to quantify "competitive". Hundreds

   of thousands of airplanes have flown with this contactor

   and I doubt that few if any owners felt compelled to

   "carry a spare". Yes, I CAN select from a variety of

   products with "better" specs . . . but in the final

   analysis, how does this affect John Q Pilot's utility

   realized from his airplane? I'm aware of NO contactors

   suited for battery service that are smaller, noise free,

   and deliver better life for the dollars spent. You've

   stirred a lot of un-quantified superlatives into this

   stew.

 	  Quote: 	
		   > Neither are most of the switches, contactors, even

 > alternators that have been used with great success

 > for decades.

Bob, that's partially true, but Kilovacs and Gigavacs can shut off your 

battery whilst saturated in fuel.  They can also shut off a runaway 

alternator. They will last forever. They cost more. They have lower hold 

currents. They use bidirectional Zeners for coil suppression. Nice, huh?

   Sure . . . but how many battery contactors have ever been

   asked to open the battery while fuel-soaked? The hold current

   electronics duty cycle switches the coil circuit and proved

   to be a noise issue in at least one instance. I was hoping

   to get one into the lab to look at DO-160 conducted and

   see how much filter was needed to quiet the puppy down.

   If I were searching for stretched convictions, I might

   offer that the electronics in the EV200 were vulnerable

   to lightning strike.

 	  Quote: 	
		   >3) Low interrupt capacity.

 > But they're never asked to interrupt anything but normal

 > pre-parking currents in aircraft . . . maybe 10A? For a

 > time, the TC aircraft industry attempted to use the

 > intermittent duty versions of these contactors for starter

 > control service and found them unsatisfactory.

You are referring to a specific application. I referring to general 

applications.

   The man was asking about a battery contactor. I was

   addressing that question. I added a note that

   the manner in which a b-lead contactor would be used

   in a proposed alternator controller, the type 70

   would be suited for that task too. The ONLY places where

   the venerable type 70 has been recommended for

   consideration in a Z-figure are situations where

   it is not required to SWITCH a heavy load, only

   CARRY them.  Starter contactors are another application

   that demands special consideration.

 	  Quote: 	
		   > However, they have proven a good value (I didn't say lasts

 > forever) in light aircraft battery contactor service.

 > In other words, the 8x more expensive 6041H series mil

 > spec contactors did not last even 4x as long. Given the

 > exceedingly light duty cycles expected from these devices

 > the way we use them (in failure tolerant systems) they

 > are of good value.

I don't disagree. They are a good value. But Omron contactors (50A) 

http://tiny.cc/sXDp3 are a 3X better value and are tiny in comparison. The 

Type 70 is long in the tooth. As you recall this latest brushfire was 

sparked by troublemaker Jeff Skiba poking around to get information on 

higher current performance. He started this....

   That's not a contactor but a fat relay. It IS rated for

   switching the same loads as a type 70 Stancor but would

   certainly not be suited for battery contactor service

   where starter currents are also impressed on the contacts.

 	  Quote: 	
		   >4) High hold current---16 ohm coil. Almost one amp.

 > Which is not an issue as long as the alternator

 > is running . . . you have power to burn. When the

 > alternator is not running, this device is turned

 > off for endurance mode operations.

An ampere here, and ampere there...pretty soon you have real power waste. 

Our philosophies differ. I remember in 1960 when you could buy surplus 

aircraft and they'd come with full fuel tanks. Not anymore.

   Philosophies differ? I'm not real sure what philosophy you're

   embracing. I think I've been quite clear as to my own.

 	  Quote: 	
		   >5) Low hold force. The specifications call for specific orientation.

 >2G rating?

 > I've tested these at over 12g. Where do you find any recommendations 

 with respect to g-loading. I can tell you that the vertical orientation 

 is to reduce potential for moisture ingress due to condensation and/or 

 splash . . . as you've noted, they are not sealed. As a battery 

 contactor, they are closed in all phases of flight and exceedingly difficult to

 > force open with g-loads.

You could be right on this. Type 70 specs are impossible to get on this, 

(and believe me I've tried). I interpret the orientation spec to be a 

g-load concern.

   Can't imagine how you get this. Mounting top down adds gravity

   to the spring tension and probably increases spreading

   velocity by some factor. It also reduces a pooling opportunity

   for ingested moisture. But to infer that this orientation

   has something to do with consideration of g-loading in

   aircraft is a real stretch. 99.9% of all such contactors

   manufactured did not go into airplanes. It's a reasonable

   extrapolation that their recommendations grew out of

   consideration for the mass market applications as opposed

   to aircraft.

 	  Quote: 	
		    But Kilovac and Gigavac and others always spec g-load. Usually 10g's.

   Those are not g-loading specs but shock and vibration

   qualifications.

   They do not address resistance to contact motion

   while energized/de-energized under linear acceleration.

   Folks have often latched onto those g-numbers and

   translated them into potential for malfunction during

   aerobatic maneuvers. They are unrelated.

   If you're going to use spec sheets as a hammer, you

   need to interpret them correctly lest the nail you

   hit is the one on your thumb.

 	  Quote: 	
		   >6) Wildly wrong for B&C to use coil suppression diodes on these. This

 >causes short lifetimes on the B&C parts.

 > I've also demonstrated that this is not true.

As I said Bob, you are wonderfully on-the-mark about thousands of things, 

and only wildly wrong about only a few.

   Make my day  . . . show me where I went wrong.

 	  Quote: 	
		  One Hundred Dollars U.S. to your favorite charity and a jar of jalapenos 

to you if an agreed upon third party will test the type-70 contactor using 

1N5401 Diodes vs. 18V SnapJacks for coil suppression in an agreed upon 

test. My winning requires you to never again espouse this bonehead notion.

   Do your own tests. I've outlined exactly what I did, how

   I made and interpreted the measurements. Where do you

   find fault with the experiment? I explained in detail how

   the authors of the oft quoted article correctly observed

   an increase in drop-out delay cased by plain vanilla diodes

   and then erroneously extrapolated this fact into a commensurate

   reduction in contact spreading velocity (i.e. extended arcing

   equals more wear).

   It's a simple bench setup . . .

   <snip>

 	  Quote: 	
		   >Better yet, avoid all contactors and use manual switches if you can.

 > This IS a stretch Eric. It's true that contactors are the

 > most highly stressed devices on an airplane after generators

 > and followed by alternators. It's also true that they are

 > a significant maintenance item on EVERY airplane from the

 > C-150 through the Hawkers. But so are tires, batteries,

 > generators, etc. The artfully crafted system tolerates

 > these service life limitations without placing the aircraft

 > or occupants at risk. Can we really recommend that anyone

 > resort to manually operated high current switches (bring

 > high current conductors within reach of pilot) just to avoid

 > a service-life issue on a 100-our a year airplane?

Bob, Stretching is a good, but not necessary thing. I recommend to my 

builder-friends using a Flaming River racecar battery switch to satisfy 

the FAA for the one-hand battery disconnect. That's what's going into my 

Glastar. No contactor needed. Most other contactors can go bye-bye too.

   Good for you! And yes, the type 70 is a legacy product but

   so are all the hammers and screwdrivers in my toolboxes. There

   are a host devices that will function as battery contactors.

   The Omron relay you cited is not one of them. If we're going

   to give advice I'll suggest that it is specific to the

   question and includes a suite of choices . . . and refrain

   from unsubstantiated fear mongering especially in light

   of repeatable experiments that demonstrate otherwise.

   Show me where the interpretation of data in the diode vs. spreading

   velocity experiment was wrong. Keep in mind too that contact

   wear in switches and contactors is more tightly linked

   to behaviors in CLOSING the contacts. Here the contacts

   bounce . . . close, open and re-close up to a dozen times

   in an ever decreasing gap where ARCING happens with each

   opening. The coil suppression technology has nothing to do

   with contact closing behaviors.

   The GX11 Gigavac is an interesting product. I've seen their

   RF vacuum relays for years but this was the first time I

   was aware of a high current contactor. They don't sell through

   distribution but I find that an old friend to mine is their

   local rep. I left a voice mail message for him asking about

   getting my hands on a GX11BAA. See:

http://aeroelectric.com/Mfgr_Data/Contactors/Gigavac/gx11.pdf

   Note that this data sheet speaks to vibration and shock

   ratings . . . NOT linear acceleration. Note further that

   they do not offer a duty-cycle switched, low holding

   current feature.  I'll get one on order and look it over.

   Bob . . .

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Sat Aug 09, 2008 7:19 am Post subject: BnC Continuous Duty Contactor 12 v

[quote]Jeff wrote:"I am using it as a battery contactor but with a Very High out alternator, 200amps ..... So I am thinking I need to find a bigger contactor ?  or my other thought - guess was maybe to run TWO Stancor 70-902 contactors in parallel ? with the extra wires also... but concern here is that something I haven't thought of will smoke something if both are not closed ? Maybe I am overlooking a simple cheaper solution...."<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />  Jeff,The size of the alternator has nothing to do with the current rating of the battery contactor.  The ampacity of the battery contactor should be determined by the engine starting current and by the battery charging current.  These two currents are the only significant currents normally flowing through the battery contactor.  Even if you have a very large load such as an electric cockpit heater, that current would flow directly from the alternator to the heater without going through the battery contactor.  Just because the alternator is rated at 200 amps does not mean that it will be supplying that much.  The alternator will only be putting out that current which is needed to operate the loads that are turned on, most likely only a fraction of the alternator's ampacity.  I would use the same battery contactor regardless of the alternator size.Joe Gores[b]

_________________
Joe Gores

nuckolls.bob(at)cox.net
Guest

Posted: Sat Aug 09, 2008 8:25 am Post subject: BnC Continuous Duty Contactor 12 v

At 11:16 AM 8/9/2008 -0400, you wrote:



 	  Quote: 	
		  Jeff wrote:



"I am using it as a battery contactor but with a Very High out alternator, 

200amps ..... So I am thinking I need to find a bigger contactor ?  or my 

other thought - guess was maybe to run TWO Stancor 70-902 contactors in 

parallel ? with the extra wires also... but concern here is that something 

I haven't thought of will smoke something if both are not closed ? Maybe I 

am overlooking a simple cheaper solution...."


	


    Interesting! Help us understand a bit more about

    your proposed system. Under what conditions would

    you expect your 200A alternator to deliver this

    kind of power. In other words, what design goals

    for the vehicle drove the selection of this size

    machine?

 	  Quote: 	
		  



Jeff,



The size of the alternator has nothing to do with the current rating of 

the battery contactor.  The ampacity of the battery contactor should be 

determined by the engine starting current and by the battery charging 

current.  These two currents are the only significant currents normally 

flowing through the battery contactor.  Even if you have a very large load 

such as an electric cockpit heater, that current would flow directly from 

the alternator to the heater without going through the battery 

contactor.  Just because the alternator is rated at 200 amps does not mean 

that it will be supplying that much.  The alternator will only be putting 

out that current which is needed to operate the loads that are turned on, 

most likely only a fraction of the alternator's ampacity.  I would use the 

same battery contactor regardless of the alternator size.



Joe Gores


	


    Joe is quite correct. The battery contactor must CARRY, not

    SWITCH starting currents that include some bodacious inrush

    currents. Then it must CARRY, not SWITCH the battery recharge

    currents and/or expected battery discharge currents during

    alternator-out operations. The 80-amp, lowly 70 series devices

    have given good service. But let's be sure that we're not

    giving you marginal advice. Do you also plan a big battery?

    If the battery is "up-sized" in concert with a larger alternator,

    then it follows that your system MIGHT be capable of extra-

    ordinary stress on the battery contactor . . . like recharging

    a big battery with you 200A energy source.



    There are some up-sized contactors not the least of which

    are the 586 series devices from Stancor.



http://aeroelectric.com/Mfgr_Data/Contactors/Stancor-WhiteRogers/Stancor_586-Series.pdf



    . . . but we don't have enough information about your

    design goals to make confident recommendations.

    Bob . . .



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

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

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

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum