Today's Message Index:
----------------------
1. 05:46 AM - Re: Toggle Switch Knob (Mark Sletten)
2. 06:58 AM - Re: Alternator Off During Start Up? (Gary Casey)
3. 07:34 AM - Re: Toggle Switch Knob (D Fritz)
4. 09:39 AM - Re: Toggle Switch Knob (Eric M. Jones)
5. 10:34 AM - koroseal cable lacing (thomas a. sargent)
6. 01:12 PM - larnin' 'lectrics (Fergus Kyle)
7. 08:06 PM - E-Bus Usage Procedure / Question (Matthew Brandes)
8. 08:21 PM - Re: E-Bus Usage Procedure / Question (Dan Checkoway)
9. 08:37 PM - Re: E-Bus Usage Procedure / Question (plaurence@the-beach.net)
Message 1
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| Subject: | Re: Toggle Switch Knob |
--> AeroElectric-List message posted by: "Mark Sletten" <marknlisa@hometel.com>
Why don't you just carve one out of wood? I carved a flap lever out of
aluminum using a grinder, but the round shape of the wheel might be
easier with wood.
Mark & Lisa Sletten
Legacy FG N828LM
http://web.hometel.com/~legacyfgkit
Message 2
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| Subject: | Re: Alternator Off During Start Up? |
--> AeroElectric-List message posted by: "Gary Casey" <glcasey@adelphia.net>
<<Automobiles live with a thing called "load dump" or "load dump transient,"
where if something shuts off or a wire breaks, the alternator output voltage
will jump way up momentarily. I forget if they design to 40 or 70 volts,
and somewhere in the car or an accessory is a huge zener to limit
overvoltage beyond that.>>
I think when push comes to shove I believe the average car will have a
slightly "quieter" electrical system than a plane. Since weight is not an
issue they have a much larger battery and larger-gage ground wires, both of
which tend to keep voltage transients down. Although, since we supply
electronic components to the auto industry we are constantly being surprised
with weird glitches that - of course - are all our fault. The "load dump"
phenomena is caused by the inductance of the field in the alternator -
imagine the alternator cranking out full current to supply a load and then
that load is suddenly removed. The voltage regulator senses the increasing
system voltage and shuts off the field. However, the field, being created
by a large coil of wire surrounding an iron core, can't be instantly
changed, so the alternator continues to produce now-excess current until the
field current decays, which takes 10's of milliseconds. The effect is
usually very slight as the battery serves to hold the voltage at a
near-constant level, absorbing the momentary excess current. The load dump
that causes big problems is when there is an open circuit at the battery and
in this case there is nothing that will absorb the current that was being
taken by the battery, whereupon the system voltage can rise to over 100
volts. Automotive systems are designed to survive this type of voltage
transient even though it is quite rare. No, there is nothing in an
automotive system specifically designed to ABSORB that transient -
everything is designed to TOLERATE it. No "huge zener."
<<I have a high compression 540 and
long starter leads. Several times I've had difficulty starting the engine
with the alt. field on. When I turn the field off it seems to crank faster
and starts easily. Is the alt putting a lot of drag on the engine when the
voltage drops on
cranking?>>
The alternator is putting negligible torque on the engine during cranking,
but it does draw a few amps (less than 5 as I recall). Would this make the
difference? I've found that the usual "observation" is that the starter has
trouble torquing the engine over the first compression stroke so the driver
tries a couple of times (then shuts off the alternator?). By that time the
compression pressure has leaked down sufficiently so that it will go past
the first compression and the rest are easy as there is some momentum built
up by then.
And by the way, in passenger cars the alternator is "on" during cranking.
Most of the accessories are turned off during cranking to reduce battery
load, NOT to protect them against any mythical voltage transients.
Incidentally, according to the wiring diagram my Cessna was originally
equipped with a relay in the avionics bus that shut it off during cranking -
long since removed.
Gary Casey
Message 3
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| Subject: | Re: Toggle Switch Knob |
--> AeroElectric-List message posted by: D Fritz <dfritzj@yahoo.com>
I'd be interested in getting one of these as well. Also, while we're discussing
switch ergonomics, does anyone know of a source of T-shaped landing light switches?
All the commercial and military aircraft I've flown have these shaped
so you can tell it's for the landing lights without looking.
Dan Fritz
---------------------------------
Message 4
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| Subject: | Re: Toggle Switch Knob |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
Eaton makes a ton of the stuff. If Marine Air Supply 800-678-6085 doesn't
have the switch tips I would be surprised.
http://www.marineairsupply.com/
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
"Life may have no meaning. Or even worse, it may have a meaning of which I
disapprove." -- Ashleigh Brilliant
Message 5
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| Subject: | koroseal cable lacing |
--> AeroElectric-List message posted by: "thomas a. sargent" <sarg314@comcast.net>
I just got some koroseal. I'm familiar with ordinary nylon cable
lacing. Koroseal is a lot thicker and stiffer. Is it used in exactly
the same way as the thin lacing (which looks to be difficult), or is
there some better practice to follow?
--
Tom Sargent
RV-6A, firewall.
Message 6
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| Subject: | larnin' 'lectrics |
--> AeroElectric-List message posted by: "Fergus Kyle" <VE3LVO@rac.ca>
Matthew,
I saw your email on AeroElectric list and note that you are new
to this form of the art............
May I recommend the AeroElectrics Connection book produced by
Bob Nuckolls, who frequents and replies to this list? Far from shooting you,
he and several others, including Brian Lloyd and many others have extensive
experience in this and radio fields.
However, I suggest that as a minimum step, you buy Bob's book
above and become familiar with the particular chapters of interest. It is
excellent, and in spite of 40 years of Amateur Radio (and 55 years in
flying), have learned much from Bob and others. Your familiarity with the
details will qualify you for serious answers we all need to complete our
favourite projects.
Good hunting!
Ferg
Europa A064
Message 7
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| Subject: | E-Bus Usage Procedure / Question |
--> AeroElectric-List message posted by: "Matthew Brandes" <matthew@n523rv.com>
I think I'm getting closer to understanding all this electrical stuff.. but I have
a question about the E-bus procedure.
(Ref. Dwg 11) So your toodling along and your alternator craps out. No big deal...
you've planned for it. The alternator is taken offline and you are ready
to switch over to your E-Bus. So you flip the e-bus switch, so the e-bus is
now drawing current from the battery side of the contactor. The diode is keeping
current from flowing back to the Main bus, HOWEVER, if the battery contactor
circuit is still closed (BAT switch On), the main bus would still be drawing
current through the contactor, yes? So with this design, if the alternator
craps out and you want to switch over to the e-bus, you need to put the master
switch in the off position, opening the battery contactor cicuit, keeping the
main bus from drawing current.
Did that make sense? Am I missing something? Procedure: Turn on the E-Bus then
turn off the Master Switch.
Matthew
RV-9A Finish Kit
'lectric newbie
Message 8
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| Subject: | Re: E-Bus Usage Procedure / Question |
--> AeroElectric-List message posted by: "Dan Checkoway" <dan@rvproject.com>
Matthew,
Yes, you got it...but...I always fly with my E-Bus switch ON. Constantly.
That way it's just one switch flip if and when the alternator dies, and
voltage to my "essentials" (some of which need initialization time, such as
the GPS) is NOT interrupted.
If you fly with the E-Bus switch ON all the time, when the alternator dies,
flip the master switch all the way off and keep flying.
Plus, this way, the devices on the E-Bus theoretically don't see the voltage
drop they otherwise would if the E-Bus was being fed through the diode. The
E-Bus is being fed from the battery bus (I think!).
Hope this makes sense, and please correct me if I'm wrong.
)_( Dan
RV-7 N714D
http://www.rvproject.com
----- Original Message -----
From: "Matthew Brandes" <matthew@n523rv.com>
Subject: AeroElectric-List: E-Bus Usage Procedure / Question
> --> AeroElectric-List message posted by: "Matthew Brandes"
<matthew@n523rv.com>
>
> I think I'm getting closer to understanding all this electrical stuff..
but I have a question about the E-bus procedure.
>
> (Ref. Dwg 11) So your toodling along and your alternator craps out. No
big deal... you've planned for it. The alternator is taken offline and you
are ready to switch over to your E-Bus. So you flip the e-bus switch, so
the e-bus is now drawing current from the battery side of the contactor.
The diode is keeping current from flowing back to the Main bus, HOWEVER, if
the battery contactor circuit is still closed (BAT switch On), the main bus
would still be drawing current through the contactor, yes? So with this
design, if the alternator craps out and you want to switch over to the
e-bus, you need to put the master switch in the off position, opening the
battery contactor cicuit, keeping the main bus from drawing current.
>
> Did that make sense? Am I missing something? Procedure: Turn on the
E-Bus then turn off the Master Switch.
>
> Matthew
> RV-9A Finish Kit
> 'lectric newbie
>
>
Message 9
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| Subject: | Re: E-Bus Usage Procedure / Question |
--> AeroElectric-List message posted by: plaurence@the-beach.net
On 4 Dec 2004 at 21:18, Matthew Brandes wrote:
> --> AeroElectric-List message posted by: "Matthew Brandes"
> <matthew@n523rv.com>
>
> I think I'm getting closer to understanding all this electrical
> stuff.. but I have a question about the E-bus procedure.
>
> (Ref. Dwg 11) So your toodling along and your alternator craps out.
> No big deal... you've planned for it. The alternator is taken offline
> and you are ready to switch over to your E-Bus. So you flip the e-bus
> switch, so the e-bus is now drawing current from the battery side of
> the contactor. The diode is keeping current from flowing back to the
> Main bus, HOWEVER, if the battery contactor circuit is still closed
> (BAT switch On), the main bus would still be drawing current through
> the contactor, yes?
Yes
So with this design, if the alternator craps out
> and you want to switch over to the e-bus, you need to put the master
> switch in the off position, opening the battery contactor cicuit,
> keeping the main bus from drawing current.
Correct
>
> Did that make sense?
Yes
Am I missing something?
No
Procedure: Turn on the
> E-Bus then turn off the Master Switch.
Correct
Peter
RV9A wings
>
> Matthew
> RV-9A Finish Kit
> 'lectric newbie
>
>
> _
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