Today's Message Index:
----------------------
1. 12:05 AM - Re: Noise filter (Doug Windhorn)
2. 12:07 AM - Re: Noise filter (Doug Windhorn)
3. 04:38 AM - Re: Multi functions for a hat switch (Terry Miles)
4. 09:17 AM - Intermittent vs. Continuous Duty Contactors (was batteries)... (Greg Campbell)
5. 10:51 AM - Re: GMCjetpilot T-shirts.. ()
6. 01:40 PM - Re: Multi functions for a hat switch (Glen Matejcek)
Message 1
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| Subject: | Re: Noise filter |
Century 1. Apparently an early model.
Doug
----- Original Message -----
From: "Ron Quillin" <rjquillin@gmail.com>
Sent: Friday, 03 August, 2007 1:08
Subject: Re: AeroElectric-List: Noise filter
>
> At 22:00 8/2/2007, you wrote:
>>A cohort is having problems with a Century autopilot induced audio noise
>>into his headphones.
>
> What model CFS system is it?
>
> Ron Q.
>
>
>
Message 2
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| Subject: | Re: Noise filter |
Negative. Sounds like you are suggesting twisted B+ and B- wires might
correct the problem. Correct?
Doug
----- Original Message -----
From: Robert Feldtman
To: aeroelectric-list@matronics.com
Sent: Friday, 03 August, 2007 3:37
Subject: Re: AeroElectric-List: Noise filter
You might try wrappig about eight wraps of the power, and control
cables through a ferrite bead (palomar engineers)- I assume you are
using twisted pair or coax shielded wire?
bobf
W5RF
On 8/3/07, Doug Windhorn <N1DeltaWhiskey@comcast.net> wrote:
<N1DeltaWhiskey@comcast.net>
Bob, et al,
A cohort is having problems with a Century autopilot induced audio
noise
into his headphones. From any testing we have done, this appears to
be
motor noise (based on spool-up/spool-down noise) transmitted into
the power
lines. The Century information indicates that it can produce noise
in some
avionics at the 5 kHz level. If it is not power line noise, then it
might
be EMF radiation being picked up by the radio or phone circuits.
I have found some information regardng design of a "twin-T
band-stop" filter
that could probably be used to filter the offending frequency out of
the
offenders power line.
Assume others have probably had this type of problem an wondering
how it was
solved.
On the dumb question front, the above circuit references a source
and load.
I would normally think of the power supply as the source and the
autopilot
the load. But, given the noise is from the autopilot, would it not
be the
source and the rest of the circuit the load?
Any insight appreciated.
Message 3
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| Subject: | Multi functions for a hat switch |
You can buy a relay board from Spruce that is designed for hat switch
purpose. Also the same can be had thru Infinity Aerospace that sells a
stick grip and has this board on his product list. Over $100 I think. Or
if you look on his website or write to him, he may have the wiring schematic
available.
Terry
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Alex
Balic
Sent: Friday, August 03, 2007 1:01 PM
Subject: AeroElectric-List: Multi functions for a hat switch
<velocity_pilot@verizon.net>
Does anyone know of a schematic that I can use to control the functions of a
hat switch using a 3 position switch to create 3 separate functions for the
hat? The 3 position switch will create the logic for the 3 functions, but I
need some sort of relay board or transistor array to change the routing of
the hat outputs and I have been penciling around and am getting a bit
stumped as to the best way to do it- any help would be appreciated- there
are 4 normally open switches on the hat and the 3 position switch uses 3
wires.......
Message 4
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| Subject: | Intermittent vs. Continuous Duty Contactors (was batteries)... |
*Bob wrote:*
This is why we SWITCH starter loads with STARTER CONTACTORS.
These have exceedingly thin and light contacts compared
to *continuous duty contactors* . . . these contacts are
*driven together with much greater force* so as to minimize
the bouncing and contact resistance. See:
http://www.aeroelectric.com/Pictures/Contactors/S702-1b.jpg
---- To which I'd like to add this little anecdote ---
I recently read where a friend of mine smelled electrical problems
while testing things on the ground and it came from using an
*intermittent duty* "starter" contactor where a
*continuous duty* "master switch" type contactor was called for.
http://groups.yahoo.com/group/Lancair_ES/message/8615
To his credit - the box he bought said it contained a continuous duty
contactor.
Unfortunately, the little metal can inside the box was an intermittent duty
contactor.
When he smelled things getting hot on the ground and saw smoke, he shut
everything off
and discovered a cooked contactor in the back and later figured out why.
(The box had contained the wrong part!)
LESSON: Check the contents of those boxes - someone may have switched them
around!
Greg
Lesson #1) - check the contents of the box to make sure it's the correct
item inside.
Lesson #2) - the "starter contactors", as Bob said, are driven together with
more force.
Typically this means their coils draw about 3 or 4 times as much current
as their "continuous duty" brothers. This means more heat in the same area.
This means that the "starter" contactors will get hot and that's why they
need
to cool off between prolonged uses.
It's all about heat dissipation - and that boils down to power over surface
area.
Most of us can relate to a 60 Watt lightbulb.
A "regular" light bulb would be the A-style bulb. You can grab one
and unscrew it after it's been on for awhile. You probably can't hold it -
but you can grab it and spin it out
Just as an example:
Intermittent Duty "Starter" Contactors - may draw 5 or 6 amps.
This lets their coils authoritatively slam the contacts together and
allows for more "spring tension" to break the connection reliably & quickly.
On a 12v system - this translates to about 60 to 70 Watts.
Continuous Duty "Master" Contactors - may draw 1 or 2 amps.
This is enough to switch an infrequent and lower current than a starter.
On a 12v system - this translates to about 12 to 24 Watts.
This comes down to a matter of dissipating the heat. That's a matter of
surface area and wattage. The contactors are typically in the same size
metal "can", so the surface area is the same.
60 Watts spread out over a large volume won't get too hot.
60 Watts spread out over a
Here's a simple way for most folks to visualize the heat dissipation.
It's mostly related to Power divided by Surface Area.
Put a 60 Watt heater inside a toaster oven and it's not much of a toaster.
Put a 60 Watt bulb inside a smaller metal box and you have an Easy Bake
oven.
Put a 60 Watt bulb inside:
- a toaster oven - and it's not much of an oven
- a small metal box and it's an Easy Bake oven
- inside a candelabra size bulb
So for anyone who's not an engineer - here's a simple way to relate
this to how hot things can get:
Imagine grabbing a common 60 Watt or 75 Watt incandescent light bulb
that's been on for an hour with your bare hand. Ouch...
Since the starter contactor is smaller than a regular "Type A" light bulb,
imagine grabbing a 60 Watt candelabra sized light bulb that's been on
for an hour. Ouch + fried skin!
Now imagine grabbing our "continous duty" starter by grabbing
a 15 Watt candelabra bulb. Warm, but not burning hot.
Mount it in a metal can with a little metal standoff bracket -
and no problem letting it run all day long.
Anyway - that's the way I visualize the power and heat dissipation issues
between an intermittent and continuous starter contactor.
It's also the way I judge how hot something should "normally" be.
For example - if you have an EFIS drawing 5 Amps @ 12V,
then you can imagine a 60 Watt light bulb inside a metal box of similar size
to the EFIS - and have enough experience to estimate how warm it might
be after an hour or two of continuous use.
But in the meantime - make sure you double check the part numbers
on your "master switch" contactors and make sure it's not an intermittent
duty!
Fly safe,
Greg
Message 5
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| Subject: | Re: GMCjetpilot T-shirts.. |
>Patrick Elliott
>Subject: AeroElectric-List: GMCjetpilot T-shirts..
>
>After seeing multiple comments about these T shirts,
>and photos of the same in other 'virtual' locations, my
>interest was piqued.
Dear Pat:
You seem obsessed with me? Should I alert the authorities?
If any thing happens to me it's Patrick....
BTW, I saw the Tee-shirt and love it. Laughed my tail
off. The guy wore the t-shirt because people last year asked
if he was me. He must be hansom. lol. I get a cut of sales!
Dude, what would possess you to write this and waste every
one's time? What have I done to you? Relevance to aircraft
wiring is what? Are you just making trouble and instigating? I
not impressed. Shame on you. You are "piqued", really? You
are the curious one.
Bob and I had a riff in the past, but all has been well for
months since I learned my lesson; I may not be smart but its
obvious the solution is to not comment, reply or debate any
of Bob's post. I got it!
I realize now the debates where only about tearing people
down and discrediting them. I should have known better than
to get suckered into these endless urination matches. It
never was about clarifying or communication, it's baiting and
argument, ostensibly to ridicule or dis-credit. Just look at the
manifesto on Bob's web site. I suppose I could get my lawyer
since I did not give him permission, but why would any one
spend so much time twisting words around? Its just simple
DC wiring. I see the motive; its not about an honest debate.
Now I don't hold grudges. I could get mad at some of the
comments made towards me and others. One of my earlier
post on aeroelectric Bob let me know he has contempt for
engineers (or persons with engineering degrees)? "I would
never hire an engineer". It sounded like a personal problem.
That should have been a clue to bail.
Who knew going to college was a waste of time and made
you retarded. This is why the USA is losing the technical
edge. Other countries have more engineering grads and
they are beating us technically, but let live, forgive and
forget, right. People are dying in Iraq, bridge collapse....
This is suppose to be fun.
This is old news Patrick, you should move on. I like to learn,
share information and deal in facts and scientific data, not all
this baloney. You posted this, to just say to me, I don't like
you, is really immature baloney. Lets talk about airplanes for
gosh sakes.
>I found and read Bob's article on why "GMCjetpilot" was
>asked to leave and some other readings, which only caused
>me to dig deeper.
Caused me to Dig deeper? Stalker? Weird. You're referring
to "the manifesto"? That's also old news also.
Are you referring to the last blow up, when I said IR
alternators be turned on BEFORE engine start and the fur
ball round of posts that ensued, which was unpleasant? Yea
I said internally regulated alternators should be turned on
before start. What was I thinking?
After 5 calls to regulator manufactures and designers, plus
friends who damaged their alternator by turning them on/off
while spinning under load, I came to my conclusion. I should
have left my comments with out debate or defense. Go
ahead, flip the ALT on after start, off before shut-down under
load, its your alternator. (This applies to stock IR ND's, not
plane-power units, which are wired differently than stock.)
Again, in the future I'll not reply, respond or debate Bob. Its
not a contest.
If I make a comment or suggestion, they will stand alone.
People who understand or appreciate my post/input will
accept them it. Others that want to fight, argue, dismiss and
ridicule my comments. Feel free. You will tango alone.
One post per topic and given with out defense. If you want
the full meal deal explanation of my research, data and
supporting facts, write me. No mystery, ask, I don't bite.
I don't know why Bob and I can't talk? One of my first post,
Bob let me know he hates engineers. "I would never hire an
engineer." Who knew going to college was a waste of time
and makes you retarded. This is why the USA is losing the
technical edge. It sounded like a personal problem.
When Bob wrote the diatribe and posted it on his site, it
starts with a quote of mine (out of context). "No offense to
Bob, but OV relays are a step backwards." That comment is
true in my opinion. We have better options, Plane-Power,
either their internal or externally regulated alternators. If you
have a stock internally regulated alternator and if you feel
you must have extra OV protection....SELL IT and buy a
plane-power unit. It's common sense. If you really care about
the BEST, than buy the best, but don't BAND AID it.
However a good quality stock unit is very reliable and
unlikely to ever fail in a severe over voltage condition, but if
you need it because your panel is expensive/sensitive or
your operations are critical (IFR) than don't mess around
with OV relays.
BTW I just found out Plane-Power will have an external
voltage regulator soon. I currently suggest the Transpo
V1200, OV protected voltage regulator for external
regulation. I do not work for P-P, but I looked into getting into
the business of making alternators for homebuilts years ago.
I gave up when I say what plane-power was doing. The did it
right with proper rotation fans, high altitude brushes,
corrosion protection and in-house manufacture of critical
parts. (B&C is a fine company that Bob has had or has a
relationship with. I just think Plane-Power offers better value,
sorry only an opinion.)
Don't put a band-aid on a cut that needs stitches.
I take full responsibility for my words and have got mad at
Bob and gave him a few digs, but it takes two tango. I
stopped dancing long ago. I realize now the debates where
only about tearing people down and discrediting them. I
should have known better than to get suckered into these
endless urination matches. Nuff said.
Folks lighten up, this is fun stuff, learning and sharing. I
support & appreciate every ones effort 100%, except all the
waste of time arguing for argument sake.
>Patrick Elliott Not on GMCJetPilots friend list.
I'll have to go on without you on my friends list? Life will
go on but will miss you Patrick "piqued" Ellliottt. I'll get a
t-shirt so you can find me at the airshow and tell me off in
person. 27 years ago I started building my first kit plane,
folks where real nice than, helpful and supportive. It would
be nice to get back to those days.
Flame suit and asbestos underwear on.
Cheers
---------------------------------
Park yourself in front of a world of choices in alternative vehicles.
Visit the Yahoo! Auto Green Center.
Message 6
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| Subject: | Re: Multi functions for a hat switch |
Hi Alex-
>...create 3 separate functions for the
>hat? ...
I know this isn't the response you were looking for, but please be careful about
what you wish for. Having multi functions for each switch on your trim system
sounds like it would be a human factors issue. For example, one day you will
accidentally fire a rocket when all you wanted was to run a little pitch trim...
It's statistically bound to happen. Perhaps not a big deal if there are
no critical, or at least time critical, functions on the switch. However, incorporating
that kind of operational complexity into your cockpit is generally
contrary to the KISS principle.
FWIW-
Glen Matejcek
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