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a : aeroelectric-list-digest@matronics.com 8 February 2006 • 3:55PM -0500

AeroElectric-List Digest: 18 Msgs - 02/07/06
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                     Total Messages Posted Tue 02/07/06: 18
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Today's Message Index:
----------------------

     1. 05:50 AM - Re: Flyable_Brassboards  (Robert L. Nuckolls, III)
     2. 05:50 AM - Re: Bus Load Analysis  (John Schroeder)
     3. 08:32 AM - Re: Wire sizing.  (Robert L. Nuckolls, III)
     4. 08:40 AM - Re: 24v lamps in 14v system  (flmike)
     5. 09:22 AM - Re: Bus Load Analysis  (Jerry Grimmonpre)
     6. 11:10 AM - Re: Wire sizing.  (Bill Dube)
     7. 11:49 AM - Re: Wire sizing.  (Robert L. Nuckolls, III)
     8. 12:46 PM - Re: Bus Load Analysis  (Matt Prather)
     9. 01:31 PM - Re: Wire sizing.  (Bill Dube)
    10. 05:02 PM - Re: Bus Load Analysis   (Jerry Grimmonpre)
    11. 05:40 PM - Dual Alternator, Response  (Mark Neubauer)
    12. 05:53 PM - Re: 12 Volt DC Bench Power Supply  (Peter Laurence)
    13. 06:25 PM - ON hold current for Bosch ice-cube relays  (Eric M. Jones)
    14. 07:01 PM - Re: Wire sizing.  (Robert L. Nuckolls, III)
    15. 07:01 PM - Re: Dual Alternator, Response  (Robert L. Nuckolls, III)
    16. 07:20 PM - Re: ON hold current for Bosch ice-cube relays  (John D. Heath)
    17. 07:45 PM - Re: ON hold current for Bosch ice-cube relays  (Robert L. Nuckolls, III)
    18. 09:16 PM - Switch Question  (Ed Holyoke)



________________________________  Message 1  _____________________________________


Time: 05:50:46 AM PST US
From: "Robert L. Nuckolls, III" <nuckollsr@cox....>
Subject: Re: AeroElectric-List: Flyable_Brassboards

--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox....>

At 11:35 PM 2/6/2006 -0500, you wrote:

>--> AeroElectric-List message posted by: "Richard E. Tasker"
><retasker@opto...>
>
>I understand what you are doing and know that you understand the
>limitations of this type of breadboard and will not use it for long or
>in any flight critical application.

    Name one "flight critical" application . . .  :-)


>However, I am not sure that everyone reading this list does.

   The operative term is "brassboard"  . . . a modern incarnation
   of the yesteryear's techniques for "breadboarding". This technology
   is useful for one-of, low bandwidth tasks. This technology is a
   low-time-to-operation but short-lived activity such as the
   examples I described for engineering flight and/or bench
   testing.

   Any permanently installed device . . . or a device not intended
   to be shepherded by flight test persons should not be assembled
   in this manner.

>This type of breadboard is good for bench testing of relatively low
>frequency (<1MHz or so) circuits.  It has a relatively large capacitance
>between pins/insertion points which limits the high frequency utility
>and can provide unwanted feedback in sensitive circuits.  It is also not
>very secure unless it is new and from a good quality manufacturer.  The
>insertion points tend to get loose with time, especially if one inserts
>a larger lead one time and a smaller lead the next.

   Absolutely. This is the ONLY reason I keep PVC, 22AWG solid wire in
   the shop. I specifically limit the size of conductors pushed into
   the holes to 22AWG or smaller.

>I would recommend that one use these boards as they were intended - try
>out the circuit on the bench in a nice benign environment.  When you are
>satisfied that it will do what you want, then purchase one of the PCBs
>available that exactly mimic the insertion points and buses and solder
>your circuit on that (for instance, Radio Shack Catalog #: 276-170  -
>http://www.radioshack.com/search/index.jsp?kwCatId=&kw=breadboard -
>fifth one down on the page).  They are also available from Digikey.
>This will give a circuit that is stable and robust and could be used as
>a permanent installation if so desired.

    VERY labor intensive by comparison and you still have to box it
    and furnish a connector. I find the spring-boards particularly
    useful in situations where you have a lot of people standing around
    charging to your work-order and things don't move ahead until YOUR
    contribution to the task is running.

    They ARE life-limited. I've refurbished several of these tools
    when one or more contacts got funky. I keep several new
    spring-boards on the shelf. It takes 10 minutes to pry the
    used one off and replace it.  They're easy to build
    and have great return on investment but as you've noted, NOT
    a substitute for more robust packaging for long term
    applications and especially when the device will be used
    by non flight test personnel. It is, after all, a brassboard.

    Bob . . .













________________________________  Message 2  _____________________________________


Time: 05:50:46 AM PST US
Subject: Re: AeroElectric-List: Bus Load Analysis
From: "John Schroeder" <jschroeder@peri...>

--> AeroElectric-List message posted by: "John Schroeder" <jschroeder@peri...>

Jerry -

I'm not sure what your point is. The AOA Sport relies on pitot and static  
pressure inputs. Therefore, in known or suspected icing, I would have the  
pitot heat on - to get both airspeed and the AOA. Why would one risk  
losing both by trying to save some juice in the weather?

I have installed this AOA in a Lancair ES. The AOA ports are on the right  
wing and the pitot tube is on the left wing.

Hope this helps.

John


On Mon, 6 Feb 2006 22:22:13 -0600, Jerry Grimmonpre <jerry@mc.n...> wrote:

> What I'm trying to get at here is: do you think pitot heat should be  
> listed
> as continuous amps used, considering the availability of AOA and it's low
> demand on amps?
> Regards ...
> Jerry Grimmonpre'



--














________________________________  Message 3  _____________________________________


Time: 08:32:49 AM PST US
From: "Robert L. Nuckolls, III" <nuckollsr@cox....>
Subject: Re: AeroElectric-List: Wire sizing.

--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox....>

At 01:28 AM 2/7/2006 -0500, you wrote:

>--> AeroElectric-List message posted by: "DEAN PSIROPOULOS"
><dean.psiropoulos@veri...>
>
>Lectric Bob:
>
>I've been doing the wiring diagrams for my all electric RV-6 and using some
>of your autocad stuff on the AEC CD as examples and starting points.  Since
>I'm just hacking at Autocad these help get me going faster than if I had to
>start from scratch, thanks for sharing your hard work with us.  Couple
>questions on wire sizing. I originally bought the Whelen strobe kit (A600)
>that has both the side and aft position lights with strobe in each wingtip
>mounted assembly (no tail position required).  I later decided to buy the
>combination tail position light/strobe combo as an addition in order to help
>people see me better from the rear.

   <snip>

    My apologies for running you thorough the 'rat race' with bad
    data. The temperature rise data in Chapter 8 lost something in
    the translation a few years ago when I crafted the figures. A number
    of readers pointed this out over the years . . . in fact, I'd
    prepared some corrected Figures for posting on the website but
    never got them finalized and posted. Here they are:

http://www.aeroelectric.com/articles/Figures_8-3_8-4_Errata.pdf

    With the correct data, you'll find that your 16AWG choice for
    the position lights will be just fine.

>Also, I see on your diagrams for landing and recognition lights you show a
>resistor of unknown value between the ground connection and the light.  I
>assume this is simply there to remind us that there is some loss in lines
>that long and also some loss in the return line (aircraft structure). Is
>this assumption correct or is there a reason for the resistors there?  Any
>other word of wisdom would be most welcome.  Thanks.

    Those are inrush limiters. See


http://www.ametherm.com/Inrush_Current/welcome.html

and

http://www.ametherm.com/Data%20Sheets/SL32%2010015.pdf

    These a thermistors with strong negative temperature
    coefficients that will greatly attenuate the 10-70x
    inrush currents to large lamps. The part cited above
    is a good one for lamps drawing 7-15 amps. You can buy
    these from Digikey . . .

http://dkc3.digikey.com/PDF/T061/1328.pdf


    I appreciate your bringing the topic up again. It prompted
    me to get my homework done on the errata sheet. I'm putting
    chapter 8 on the to-do list for Revision 12. Thanks!

    Bob . . .













________________________________  Message 4  _____________________________________


Time: 08:40:55 AM PST US
From: flmike <flmike2001@yaho...>
Subject: AeroElectric-List: Re: 24v lamps in 14v system

--> AeroElectric-List message posted by: flmike <flmike2001@yaho...>

try:
http://www.aconinc.com/web05/s24v.html

they also have 28V output units in case that's what
you really need.

If just powering the LED position lights, size the
convertor according to the power consumption of the
lights.  I'm assuming this is an experimental plane?

Mike













________________________________  Message 5  _____________________________________


Time: 09:22:49 AM PST US
From: "Jerry Grimmonpre" <jerry@mc.n...>
Subject: Re: AeroElectric-List: Bus Load Analysis

--> AeroElectric-List message posted by: "Jerry Grimmonpre" <jerry@mc.n...>

DO NOT ARCHIVE
Hi John ...
Thanks for your note, I was trying to make the point of declaring the
"constant on" of the pitot heat to be an excessive "charge" to the account
of bus demand.  Sort of like the "constant on" of a Com radio does not
consider the moments of transmit to be considered demand on the bus because
of the duration of transmit time.

I see, from your response, the that the AOA does require pitot/static and,
of course, that can only come from a non iced system.  I had it in my mind
that the AOA Sport only required inputs from the two ports on the wing D
section.   Thanks for your enlightenment.
Regards ...
Jerry Grimmonpre'



> --> AeroElectric-List message posted by: "John Schroeder"
> <jschroeder@peri...>
>
> Jerry -
>
> I'm not sure what your point is. The AOA Sport relies on pitot and static
> pressure inputs. Therefore, in known or suspected icing, I would have the
> pitot heat on - to get both airspeed and the AOA. Why would one risk
> losing both by trying to save some juice in the weather?
>
> I have installed this AOA in a Lancair ES. The AOA ports are on the right
> wing and the pitot tube is on the left wing.
>
> Hope this helps.
>
> John
>
>
> On Mon, 6 Feb 2006 22:22:13 -0600, Jerry Grimmonpre <jerry@mc.n...> wrote:
>
>> What I'm trying to get at here is: do you think pitot heat should be
>> listed
>> as continuous amps used, considering the availability of AOA and it's low
>> demand on amps?
>> Regards ...
>> Jerry Grimmonpre'
>
>
> --
>
>
>














________________________________  Message 6  _____________________________________


Time: 11:10:54 AM PST US
From: Bill Dube <william.p.dube@noaa...>
Subject: Re: AeroElectric-List: Wire sizing.

--> AeroElectric-List message posted by: Bill Dube <william.p.dube@noaa...>

Paralleling small gage wires is not a good practice. If one becomes
disconnected, the other gets too hot. No way to tell that this is
occurring (other than the resultant fire.)

16 gage wire would allow a 15 amp breaker. 11 amps would be 73% of the
breaker rating. Since the load is continuous, 80% maximum is prudent.

The voltage drop for 11 amps in a 20 foot 16 gage wire could be as much
as a volt. This could make the lights a touch dim.

    If you run 14 gage wire, you can use a 20 amp circuit breaker, and
the voltage drop will be only 0.6 volts. Sounds like the better plan to me.

DEAN PSIROPOULOS wrote:

>--> AeroElectric-List message posted by: "DEAN PSIROPOULOS" <dean.psiropoulos@veri...>
>
>Lectric Bob:
>
>I've been doing the wiring diagrams for my all electric RV-6 and using some
>of your autocad stuff on the AEC CD as examples and starting points.  Since
>I'm just hacking at Autocad these help get me going faster than if I had to
>start from scratch, thanks for sharing your hard work with us.  Couple
>questions on wire sizing. I originally bought the Whelen strobe kit (A600)
>that has both the side and aft position lights with strobe in each wingtip
>mounted assembly (no tail position required).  I later decided to buy the
>combination tail position light/strobe combo as an addition in order to help
>people see me better from the rear.  
>
>I now have 5 position lights at 2.2 amps each for a total of 11 amps of load
>on the circuit. I would like to run them all from one switch and have ONE
>wire running from the switch down through the center console of the airplane
>through the spar to a distribution block under the floor.  I've been
>scratching my head a little and reading and re-reading the section in your
>book about "Wire Selection and Installation".  Using the chart for temp rise
>vs wire ga vs current capacity, it looks like a 16 GA wire would have appx a
>30 deg C temp rise with 11 amps flowing through it. If I convert that to an
>appx Farenheit equivalent it becomes something like an 86 deg temp rise.  If
>ambient is a Florida summer with the OAT at 90 deg (F) and I add these two
>temps together I get 176 degrees (F) temp in free air with 11 amps in the 16
>GA wire, correct?
>
>Running this wire down through the tight confines of my center console means
>that it will be near several other wires and without lots of cooling air so
>I would assume that one would see the full 176 degrees around that wire in
>that confined space.   This is not beyond the capabilities of the Tefzel
>wire I'm using but still very hot to the touch and warmer than I feel
>comfortable with.  So if I drop down to a 14 GA wire it looks like the temp
>rise would be appx 13 deg C or 55 F which gives about a 145 deg wire temp in
>free air.  The is still going to be pretty warm to the touch and I'm
>thinking maybe it should be derated a bit more but don't really want to run
>a 12 GA wire and am not 100% sure it's needed (although on a night flight
>that wire will see the full 11 amps for the entire period of time).  
>
>Are my assumptions here correct and am I really going to experience 176 deg
>wire temp with 11 amps in a 16 GA wire on a 90 deg day? If so do you think
>dropping to 14 GA would be sufficient or should I make it larger?  Since I
>don't really want to run a 12 GA wire through the tight space would two 16
>or 14 GA wires work equally as well or would the current shared by each be
>unequal with the resultant heating of each wire also unequal (assuming they
>are tied together at both ends)?  Is there a good "rule of thumb" for wire
>sizing with respect to temp rise (ie. Equipment that runs continuously
>should not have wire temps higher that would be uncomfortable to touch or
>some such thing). Since this wire is only about 6 feet long the voltage drop
>through it shouldn't be a significant factor that I see (4/1000 ohms per
>foot*6 feet*14 volts = .33 volts) so that leaves temperature.  
>
>Also, I see on your diagrams for landing and recognition lights you show a
>resistor of unknown value between the ground connection and the light.  I
>assume this is simply there to remind us that there is some loss in lines
>that long and also some loss in the return line (aircraft structure). Is
>this assumption correct or is there a reason for the resistors there?  Any
>other word of wisdom would be most welcome.  Thanks.
>
>Dean Psiropoulos
>RV-6A  N197DM
>Knee deep in Autocad and wire
>
>
>
>
>
>
>
>  
>












________________________________  Message 7  _____________________________________


Time: 11:49:52 AM PST US
From: "Robert L. Nuckolls, III" <nuckollsr@cox....>
Subject: Re: AeroElectric-List: Wire sizing.

--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox....>

At 12:01 PM 2/7/2006 -0700, you wrote:

>--> AeroElectric-List message posted by: Bill Dube <william.p.dube@noaa...>
>
>Paralleling small gage wires is not a good practice. If one becomes
>disconnected, the other gets too hot. No way to tell that this is
>occurring (other than the resultant fire.)
>
>16 gage wire would allow a 15 amp breaker. 11 amps would be 73% of the
>breaker rating. Since the load is continuous, 80% maximum is prudent.
>
>The voltage drop for 11 amps in a 20 foot 16 gage wire could be as much
>as a volt. This could make the lights a touch dim.
>
>     If you run 14 gage wire, you can use a 20 amp circuit breaker, and
>the voltage drop will be only 0.6 volts. Sounds like the better plan to me.

    The full current doesn't flow in the longest wire. Position lights
    are an excellent example of a "branching" architecture where
    a number of small loads added together determine the size of the
    bus feeder.

    His 5 x 2.2A lamps says that a 15A breaker/fuse feeding a switch
    calls for a single strand of 16AWG. From the switch outward, the
    circuit branches to various locations (left, right tail) such that
    no conductor need carry full load past the switch. Voltage drops
    will be VERY low.

    Bob . . .













________________________________  Message 8  _____________________________________


Time: 12:46:41 PM PST US
Subject: Re: AeroElectric-List: Bus Load Analysis
From: "Matt Prather" <mprather@spro...>

--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro...>

Hi Jerry,

Interesting question..  Comments embedded.

> --> AeroElectric-List message posted by: "Jerry Grimmonpre"
> <jerry@mc.n...>
>
> Hi all ...
>
> I humbly ask for input on the following and maybe create new thought ...
> Load analysis:  Pitot heat load vs. load of AOA (angle of attack) Sport
> instrument.
> Rob are you here?
>
> When considering the imbalance of the load effects of these two items
> ... it  seems we squander a lot of amps on pitot heat when the AOA could
> substitute  while using about .4 amps and include audible warnings, as
> well, while  landing at any weight.
>
> In my reading of the Lancair list, I've found there has been zero
> incidents  of moisture problems in the  AOA ports in the outer wing D
> sections.  This  included heavy rain with the airplane tied outside.  If
> this port is not  affected by moisture, it seems to follow that icing
> may be less of a problem  with this delta P port.   This applies to the
> AOA system called AOA Sport,  where the pressure differential is
> measured at the outboard wing D section.
>

I don't know that you could say that being impervious to rain has any
bearing on being impervious to ice.  Even if ice doesn't end up covering
either port, it changes the airflow over the wing, and lowers the angle of
attack of stall.  I had a fortunate opportunity to ride around in the
right seat of a Pilatus PC-12 last week..  The pilot was explaining to me
that when prop deice, and the engine inertial seperator were enabled, the
stick shaker/pusher would activate at 8deg less AoA(!).  The system
assumes that when you have both systems enabled, it's pretty likely you
are in icing conditions.

> When considering pitot heat, as a 7.5A continuous load, it would
> increase  most Continuous Bus loads by near 30-40%.  Powering-up an AOA
> system pales  in comparison at only .4 amps.
>
> Those of you with the AOA Sport ... have you found any moisture or
> frozen  ports?
> How many have found pitot heat cleared up their airspeed indications
> within  moments of turning on the pitot heat?
>

Typical use of pitot heat is to power it up whenever you are in visible
moisture - the idea is that you don't want a dead ASI to be the indication
that the pitot heat should be turned on.

> What I'm trying to get at here is: do you think pitot heat should be
> listed  as continuous amps used, considering the availability of AOA and
> it's low  demand on amps?

That's a slightly different question..  The pitot heat is a continuous
load - like nav lights.  Unlike flap motors and electric landing gear
equipment, which are momentary loads.  The real question I would ask is
whether either an AOA or the ASI is required in order to comfortably
complete any flight you intend to use the airplane for.

I don't know that this rationale is backed up by good statistics, but if I
were planning to use an airplane for lots of real IFR work, I'd probably
want a power budget that allowed me to run the pitot heat after the
failure of my primary engine driven electrical power source.  Especially
with a naturally aspirated (rather limited service ceiling) engine.  If
however, my airplane was going to be used for occasional scud avoidance -
punch through a layer in order to find some sunshine when it's cloudy on
the ground, I wouldn't worry about having pitot heat be supported by the
endurance bus.  I figure that the intersection of time when I have an
electrical failure, and when I can't comfortably complete a flight without
the ASI/AoA would be exceedingly low.


> Regards ...
> Jerry Grimmonpre'
>
>

Matt-
















________________________________  Message 9  _____________________________________


Time: 01:31:50 PM PST US
From: Bill Dube <william.p.dube@noaa...>
Subject: Re: AeroElectric-List: Wire sizing.

--> AeroElectric-List message posted by: Bill Dube <william.p.dube@noaa...>

Well I guess as long as he can make it from the switch to the wingtip
using less than 23 feet of wire, he can stay within the allowed 0.5 volt
drop using 16 gage wire.

(4.81/1000)*4.4*23 = 0.5 volts

The wing is about 10 feet long. I'm not sure how much wire it will take
to get from the wing root to the switch, but 10 feet might be a good
guess. Probably would be OK.

The difference in weight between 16 gage and 14 gage for the whole
system would be something like 0.3 lbs.

Robert L. Nuckolls, III wrote:

>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox....>
>
>At 12:01 PM 2/7/2006 -0700, you wrote:
>
>  
>
>>--> AeroElectric-List message posted by: Bill Dube <william.p.dube@noaa...>
>>
>>Paralleling small gage wires is not a good practice. If one becomes
>>disconnected, the other gets too hot. No way to tell that this is
>>occurring (other than the resultant fire.)
>>
>>16 gage wire would allow a 15 amp breaker. 11 amps would be 73% of the
>>breaker rating. Since the load is continuous, 80% maximum is prudent.
>>
>>The voltage drop for 11 amps in a 20 foot 16 gage wire could be as much
>>as a volt. This could make the lights a touch dim.
>>
>>    If you run 14 gage wire, you can use a 20 amp circuit breaker, and
>>the voltage drop will be only 0.6 volts. Sounds like the better plan to me.
>>    
>>
>
>    The full current doesn't flow in the longest wire. Position lights
>    are an excellent example of a "branching" architecture where
>    a number of small loads added together determine the size of the
>    bus feeder.
>
>    His 5 x 2.2A lamps says that a 15A breaker/fuse feeding a switch
>    calls for a single strand of 16AWG. From the switch outward, the
>    circuit branches to various locations (left, right tail) such that
>    no conductor need carry full load past the switch. Voltage drops
>    will be VERY low.
>
>    Bob . . .
>
>
>
>
>
>
>
>  
>













________________________________  Message 10  ____________________________________


Time: 05:02:14 PM PST US
From: "Jerry Grimmonpre" <jerry@mc.n...>
Subject: Re: AeroElectric-List: Bus Load Analysis    

--> AeroElectric-List message posted by: "Jerry Grimmonpre" <jerry@mc.n...>

DO NOT ARCHIVE
Hi Matt ...

> Typical use of pitot heat is to power it up whenever you are in visible
> moisture - the idea is that you don't want a dead ASI to be the indication
> that the pitot heat should be turned on.

There-in lies the problem.  AOA Sport will not indicate properly with an
iced pitot/static because AOA Sport relies on those two to feed the computer
creating the progressive decay indications of the AOA LED's.  It would seem
great to have an AOA idicator impervious to icing but the reality is the
wing's AOA and it's resultant lift reports the truth ... the wing demands
clean airflow.  Therefore an iced pitot/static OR AOA ports will not report
a reliable warning indication so plan to leave the pitot heat on when in
icing conditions and forget the AOA as being ice proof.
>
>> What I'm trying to get at here is: do you think pitot heat should be
>> listed  as continuous amps used, considering the availability of AOA and
>> it's low  demand on amps?

I just answered my own question .... yes, leave pitot heat on continuously
in icing conditions and therefore plan the bus load analysis for the 7.5
amps required.
>
>  The real question I would ask is
> whether either an AOA or the ASI is required in order to comfortably
> complete any flight you intend to use the airplane for.

An aviator who knows the airplane will know what power/attitude/descent rate
will result in getting to the end of the runway in a normal landing
configuration.

>
> I don't know that this rationale is backed up by good statistics, but if I
> were planning to use an airplane for lots of real IFR work, I'd probably
> want a power budget that allowed me to run the pitot heat after the
> failure of my primary engine driven electrical power source.  Especially
> with a naturally aspirated (rather limited service ceiling) engine.  If
> however, my airplane was going to be used for occasional scud avoidance -
> punch through a layer in order to find some sunshine when it's cloudy on
> the ground, I wouldn't worry about having pitot heat be supported by the
> endurance bus.  I figure that the intersection of time when I have an
> electrical failure, and when I can't comfortably complete a flight without
> the ASI/AoA would be exceedingly low.
>
I agree.
>>
>>
>
> Matt-
>
>
Jerry Grimmonpre'














________________________________  Message 11  ____________________________________


Time: 05:40:19 PM PST US
From: "Mark Neubauer" <markn@fuse...>
Subject: AeroElectric-List: Dual Alternator, Response

--> AeroElectric-List message posted by: "Mark Neubauer" <markn@fuse...>

Folks:

Thanks for the response about my question of using the two alternators
simultaneously. In line with what I had thought during the design of the
electrical system, I will plan to use the SD-8 only as a back-up when/(if)
the main 40amp fellow heads to greener pastures. Of course, in line with
Bob's philosophy of exercising all things electrical from time to time, it
would make sense to shut off the main alternator and energize the SD-8 (on
downwind to landing, for example, in daylight) every now and then just to
keep the electrons knowing where to go within the rather un-used wiring and
to verify, via the voltmeter, that the SD-8 is indeed pumping and keeping
the busses filled.

Mark Neubauer















________________________________  Message 12  ____________________________________


Time: 05:53:38 PM PST US
From: "Peter Laurence" <PLaurence@the-...>
Subject: RE: AeroElectric-List: 12 Volt DC Bench Power Supply

--> AeroElectric-List message posted by: "Peter Laurence" <PLaurence@the-...>


In a message dated 02/03/2006 10:20:21 PM Central Standard Time,
nuckollsr@cox.... writes:
>Can someone recommend a source/model of bench power supply using 110V AC
>input with 12V DC output, capable of up to 15 amps DC?
>>>

Might want to look at this 13.8, 20 amp supply:

http://mpja.com/productview.asp?product=5386+PS


>From The PossumWorks in TN
Mark Phillips RV-6A N51PW

Or try http://www.web-tronics.com/25ampswitpow.html 25 amps, 13.8 v for
$99.00 Hard to beat!


Peter Laurence

























________________________________  Message 13  ____________________________________


Time: 06:25:41 PM PST US
Subject: AeroElectric-List: ON hold current for Bosch ice-cube relays
From: "Eric M. Jones" <emjones@char...>

--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@char...>

Does anyone have the typical ON hold current for the high-current Bosch relays
such as Bosch p/n 0 332 209 150 ?

--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones@char...




Read this topic online here:

http://forums.matronics.com/viewtopic.php?p=10747#10747


















________________________________  Message 14  ____________________________________


Time: 07:01:00 PM PST US
From: "Robert L. Nuckolls, III" <nuckollsr@cox....>
Subject: Re: AeroElectric-List: Wire sizing.

--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox....>

At 02:25 PM 2/7/2006 -0700, you wrote:

>--> AeroElectric-List message posted by: Bill Dube <william.p.dube@noaa...>
>
>Well I guess as long as he can make it from the switch to the wingtip
>using less than 23 feet of wire, he can stay within the allowed 0.5 volt
>drop using 16 gage wire.
>
>(4.81/1000)*4.4*23 = 0.5 volts
>
>The wing is about 10 feet long. I'm not sure how much wire it will take
>to get from the wing root to the switch, but 10 feet might be a good
>guess. Probably would be OK.

    Keep in mind too that the 0.5 volt value is a rule-of-thumb.
    Consider that we expect things to perform in a useful way all the
    way down to battery-only ops of 11.0 volts. That's a whole lot more
    than 0.5 volts below a 14.2 volt bus when alternator is operating
    normally. If your "thumb" should turn out to be 0.6 or 0.7 or even
    0.8 volts long, it's not going to make a big difference in the
    over-all scheme of things.

    In fact, keep in mind that every 5% drop in voltage doubles the life
    of a lamp. Run your lights with wire that allows a 10% drop will 4x
    the lamp life . . . if that's your design goal, then so be it.
    Just tell interested parties that your thumb is "1.4 volts long."

    Bob . . .













________________________________  Message 15  ____________________________________


Time: 07:01:00 PM PST US
From: "Robert L. Nuckolls, III" <nuckollsr@cox....>
Subject: Re: AeroElectric-List: Dual Alternator, Response

--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox....>

At 08:38 PM 2/7/2006 -0500, you wrote:

>--> AeroElectric-List message posted by: "Mark Neubauer" <markn@fuse...>
>
>Folks:
>
>Thanks for the response about my question of using the two alternators
>simultaneously. In line with what I had thought during the design of the
>electrical system, I will plan to use the SD-8 only as a back-up when/(if)
>the main 40amp fellow heads to greener pastures. Of course, in line with
>Bob's philosophy of exercising all things electrical from time to time, it
>would make sense to shut off the main alternator and energize the SD-8 (on
>downwind to landing, for example, in daylight) every now and then just to
>keep the electrons knowing where to go within the rather un-used wiring and
>to verify, via the voltmeter, that the SD-8 is indeed pumping and keeping
>the busses filled.

    You can pre-flight check it. In fact, this is one of several
    design goals for being able to turn either alternator on or off
    at any time under any conditions. During mag check at elevated
    RPM you could cycle the alternators to see that both are alive.

    Bob . . .

      < What is so wonderful about scientific truth...is that >
      < the authority which determines whether there can be   >
      < debate or not does not reside in some fraternity of   >
      < scientists; nor is it divine. The authority rests     >
      < with experiment.                                      >
      <                            --Lawrence M. Krauss       >













________________________________  Message 16  ____________________________________


Time: 07:20:27 PM PST US
From: "John D. Heath" <altoq@cebr...>
Subject: Re: AeroElectric-List: ON hold current for Bosch ice-cube relays

--> AeroElectric-List message posted by: "John D. Heath" <altoq@cebr...>

Eris

0.160 amps (~75 ohm coil)

John D.

From: "Eric M. Jones" <emjones@char...>
Sent: Tuesday, February 07, 2006 8:24 PM
Subject: AeroElectric-List: ON hold current for Bosch ice-cube relays


> --> AeroElectric-List message posted by: "Eric M. Jones"
> <emjones@char...>
>
> Does anyone have the typical ON hold current for the high-current Bosch
> relays such as Bosch p/n 0 332 209 150 ?
>
> --------
> Eric M. Jones
> www.PerihelionDesign.com
> 113 Brentwood Drive
> Southbridge, MA 01550
> (508) 764-2072
> emjones@char...
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=10747#10747
>
>
>













________________________________  Message 17  ____________________________________


Time: 07:45:22 PM PST US
From: "Robert L. Nuckolls, III" <nuckollsr@cox....>   relays
Subject: Re: AeroElectric-List: ON hold current for Bosch ice-cube   relays

--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox....>
relays

At 06:24 PM 2/7/2006 -0800, you wrote:

>--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@char...>
>
>Does anyone have the typical ON hold current for the high-current Bosch
>relays such as Bosch p/n 0 332 209 150 ?


     I don't have that part number but a quick look at the variety
     of beer-can and plastic automotive relays in my stock show that
     at room temperature, they pick up at about 50% of rated and hold
     down to 15-25% of rated voltage. As temperature of relay goes
     up, the hold current will be relatively constant while the hold
     voltage climbs due tempco of copper in the coil.

     Bob . . .













________________________________  Message 18  ____________________________________


Time: 09:16:03 PM PST US
From: "Ed Holyoke" <bicyclop@pacb...>
Subject: AeroElectric-List: Switch Question

--> AeroElectric-List message posted by: "Ed Holyoke" <bicyclop@pacb...>

Howdy,

I wish to use two switches to control two batteries as follows:
I want the bottom position to be off.
I want the center position to be battery contactor on and alternator
field on.
I want the top position to be e-bus alternate feed on and alternator
field off.

Is this doable? What kind of switch do I need. How would I wire it?

Thanks,

Ed Holyoke


















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