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Beemer

Joined: 26 Aug 2006
Posts: 87
Location: Middle Georgia

Posted: Tue Nov 04, 2008 2:26 pm Post subject: FAQ question...

From the list FAQ:



 	  Quote: 	
		  

>Hmmm. My understanding is different. As wired in my plane, the OV module shorts the breaker

as you say. However, when the circuit breaker pops it kills the voltage to the field of the

contactor which is connecting the alternator output (B lead) to the battery, thus removing the

offending voltage from the system whether or not the alternator field is receiving power internally

to the alternator itself.



A Internally and externally regulated alternators ARE slightly different in the way that the

OVM tames a runaway alternator. For internally regulated machines, the external B-lead

contactor is not necessary. Bob . . . 	


Bob,

Is the above response a typo? Figure Z-24 was conceived FOR an IR alternator, no? It basically adds an alt disconnect contactor and shows how to wire it up. But the above comment suggests it is not necessary.



I'm confused...

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_________________
Beemer
KF2 (and now an M3!)
Suzuki G10 three-banger
Middle Georgia

nuckolls.bob(at)cox.net
Guest

Posted: Thu Nov 06, 2008 7:33 am Post subject: FAQ question...

At 02:26 PM 11/4/2008 -0800, you wrote:

 	  Quote: 	
		  



 >From the list FAQ:

 >

 > >Hmmm. My understanding is different. As wired in my plane, the OV 

 module shorts the breaker

 > as you say. However, when the circuit breaker pops it kills the voltage 

 to the field of the

 > contactor which is connecting the alternator output (B lead) to the 

 battery, thus removing the

 > offending voltage from the system whether or not the alternator field 

 is receiving power internally

 > to the alternator itself.

 >

 > A Internally and externally regulated alternators ARE slightly 

 different in the way that the

 > OVM tames a runaway alternator. For internally regulated machines, the 

 external B-lead

 > contactor is not necessary. Bob . . .



Bob,

Is the above response a typo? Figure Z-24 was conceived FOR an IR 

alternator, no? It basically adds an alt disconnect contactor and shows 

how to wire it up. But the above comment suggests it is not necessary.


	


    Understand. Yes that is a typo. For externally regulated

    machines, it's easy to tame a runaway system by breaking

    the field power lead. To do the same thing on an internally

    regulated hardware, you have to modify it (like Plane-Power)

    to get access to the field power path . . . or do some form

    of external disconnect of the b-terminal as suggested in

    Z-24 and the document I published at:



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



    I mentioned a trip to visit Motorcar Parts of America

    alternator and starter fabrication facilities last

    month. What I learned one that trip re-enforces my

    understanding for achieving design goals on an ON/OFF,

    any time, any conditions control of an internally regulated

    alternator.



    Z-24 is just fine for alternators designed and tested

    to survive their own load dumps . . . like the MPA

    products. Unfortunately, some alternators are not blessed

    with such diligence on the part of their designers.



    Bob . . .



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

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

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

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Beemer

Joined: 26 Aug 2006
Posts: 87
Location: Middle Georgia

Posted: Thu Nov 06, 2008 2:39 pm Post subject: FAQ question...

I feel comfortable with the alternator disconnect solenoid in series with

the "control" wire on my IR alternator. If I should feel the need to throw

the Master DC switch to the BATT position, my alternator will simply become

a spinning weight up front.



I'm installing the OVM-14 on the 5 amp CB on the panel, so the only thing

yet missing from my panel is the 2x4 coming at me during the over/under

voltage event. I'm still considering options for which way I want to go, and

the B&C BC207-1 is looking right for the job.



Bradley



<snip>



    Understand. Yes that is a typo. For externally regulated

    machines, it's easy to tame a runaway system by breaking

    the field power lead. To do the same thing on an internally

    regulated hardware, you have to modify it (like Plane-Power)

    to get access to the field power path . . . or do some form

    of external disconnect of the b-terminal as suggested in

    Z-24 and the document I published at:



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



    I mentioned a trip to visit Motorcar Parts of America

    alternator and starter fabrication facilities last

    month. What I learned one that trip re-enforces my

    understanding for achieving design goals on an ON/OFF,

    any time, any conditions control of an internally regulated

    alternator.



    Z-24 is just fine for alternators designed and tested

    to survive their own load dumps . . . like the MPA

    products. Unfortunately, some alternators are not blessed

    with such diligence on the part of their designers.



    Bob . . .



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

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

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

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

_________________
Beemer
KF2 (and now an M3!)
Suzuki G10 three-banger
Middle Georgia

nuckolls.bob(at)cox.net
Guest

Posted: Fri Nov 07, 2008 6:05 am Post subject: FAQ question...

At 05:38 PM 11/6/2008 -0500, you wrote:

 	  Quote: 	
		  



I feel comfortable with the alternator disconnect solenoid in series with

the "control" wire on my IR alternator. If I should feel the need to throw

the Master DC switch to the BATT position, my alternator will simply become

a spinning weight up front.



I'm installing the OVM-14 on the 5 amp CB on the panel, so the only thing

yet missing from my panel is the 2x4 coming at me during the over/under

voltage event. I'm still considering options for which way I want to go, and

the B&C BC207-1 is looking right for the job.


	


    I designed the BC207 to fill a niche on ultralights. If you

    have OV protection, you do not need OV warning. That light

    will be on and off so fast that you won't notice it. This

    leaves only LV warning. I used to offer a LV warning product

    but discontinued it in favor of a quantum jump upgrade.

    Details are available at:



http://www.aeroelectric.com/DIY/LV_Warn_Fab_and_Install.pdf



    . . . if you're willing to spend some time with a soldering

    iron and herd a few parts, you can craft his device yourself.

    Alternatively, we're working on a new stable of products

    from the 'Connection that will include this guy . . .



http://aeroelectric.com/Catalog/AEC/9011/9011-700-1C.pdf



    It has three functions which may be used in any combination

    and would provide your LV warning. Additionally, the second

    LV warning channel could be used to monitor any present

    or future AUX Battery installation to remind you to bring it

    on line after engine start when that battery is used to

    support products not designed to live in the real world

    of airplanes.



    It will be in the same ball park for price as the BC207.

    I'm looking into practicality of having it also control

    the b-lead disconnect contactor in a Z-24 like installation.

    Jury is still out on that.



    Bob . . .

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