Today's Message Index:
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1. 07:28 AM - Re: ZTRON LABS ZL-BP4/8 (Robert L. Nuckolls, III)
2. 08:02 AM - Re: Fw: new stuff (Robert L. Nuckolls, III)
3. 08:26 AM - Re: ZTRON LABS ZL-BP4/8 (user9253)
4. 08:28 AM - RG Batteries: I learned something last night (Robert L. Nuckolls, III)
5. 09:10 AM - Re: new stuff (Eric M. Jones)
6. 05:04 PM - Re: Re: Canopy Switch (B Tomm)
Message 1
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Subject: | Re: ZTRON LABS ZL-BP4/8 |
At 04:30 PM 10/28/2011, you wrote:
>
>10/28/2011
>
>Hello Bob Nuckolls, I am interested in your reaction to this product:
>
>http://www.ztronlabs.com/products/bp8/brochure.pdf
I have no doubt that they perform as
advertised. But unlike the legacy breaker/
fuse + switch combinations, the features
give rise to new questions.
First, what deficiencies in the design,
installation, maintenance and cost of ownership
for breaker/fuse+switch are eliminated or at
least mitigated by the new product? In
other words, are there demonstrable, compelling
performance gains for adopting this product?
Are they more reliable? In other words, has
history offered cases where the B/F+S combination
has failed to perform it's intended task?
Are the new devices less likely to repeat any
such events assuming they exist? Their
parts-count is higher . . . and certainly part
vulnerable to external stimulus for which
DO-160 was crafted to explore.
If not a reliability trade-off, then are
they less expensive to own, operate and
service? $190 for eight controlled positions
works out to nearly $25 per position. Certainly
competitive with B+S but not with F+S
configurations.
Convenience? Hmmm . . . you cut a big
hole in the panel to mount a big electro-
whizzy that shares form, fit and function
with no other product like it. Suppose
you only need 6 of the positions . . . or
need 9? These controls do not offer the
flexibility of multi-function toggles
with spring loading and progressive
transfers.
Unlike the toggle with immediately recognizable
position, these devices use lights. Are
they sunlight viewable?
This device is not a drop-in replacement
for all protected and controlled circuits
in the airplane . . so your almost sure
to have alternative hardware tucked away
on the panel anyhow.
Then there is the question as to how well
the designers understand the legacy aircraft
environment. Maybe they didn't do DO-160
verification but were they cognizant of the
design tools and processes that go to passing
a DO-160 verification?
Everyone needs to make up their own mind
as to what features of reliability, convenience,
cost and STYLE goes to meeting personal
design goals on their project. I'll suggest
that there are few technical and even fewer
economic incentives for adapting such a
product to an OBAM aircraft. But when it
comes to style, there's no accounting for
taste.
Bob . . .
Message 2
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Subject: | Re: Fw: new stuff |
At 06:52 PM 10/28/2011, you wrote:
>Has anyone looked into these? Could they achieve a gas tight connection?
Sure. Look at the list of patents at the
bottom of the home page. You can browse these
at freepatentsonline.com
These are the real deal. But they are not simple
nor will they be cheap. Probably quite attractive
to conducting some field repair/modification task
but certainly not cost or space effective in the
production environment.
Bob . . .
Message 3
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Subject: | Re: ZTRON LABS ZL-BP4/8 |
A fuse holder costs much less and models are available to hold up to 20 fuses.
http://www.amazon.com/Bussman-holder-Truck-electrical-application/dp/B0026BK6GY/ref=sr_1_10?ie=UTF8&qid=1313369427&sr=8-10
I have had trouble operating capacitance type switches when my fingers are cold
and dry or when wearing gloves. If one of those 8 switches goes bad, the whole
unit will have to be removed for repair or replacement. If the company goes
out of business, it will be a challenge to fill the hole in the panel with some
type of replacement. An aircraft builder has the skills to replace a fuse
or switch, but might not be able to repair electronic switches. There are nice
looking discrete illuminated switches available.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=356263#356263
Message 4
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Subject: | RG Batteries: I learned something last night |
That bench test battery I featured in a posting
a few days ago had not be cap-checked in several years.
The thing is over ten years old and has yielded a
great return on investment.
I did a load test on this battery about a week ago.
It dumped about 300A for 15 seconds at the 70F mark
on the load meter. A value that is less than 1/2 the
as-new capability.
Just for grins, I pulled out the CBAII battery tester.
The bench battery had been on a maintainer for a couple days.
I did a 6A discharge test. The value I use as exemplary
of most of my instrumentation experiments. The battery
delivered 24+ a.h. of useful energy! Going to the
factory data on this battery we see:
http://www.aeroelectric.com/Pictures/Curves/33AH_12V_Capacity_vs_Load.gif
The factory says a 6.6A load will deplete this battery
in about 4 hours . . . or 24+ a.h.
In years past, my teachers modeled the battery as a large
array of cells connected in a series-parallel configuration
with EACH cell offering some finite energy value combined
with it's own source impedance. If you loose 1/2 the cell
in the full-up array, energy drops by 1/2 but source impedance
doubles.
This experiment last night showed that while the source
impedance for the battery had doubled (1/2 the cranking
snort), the total energy available was still almost as-new!
This means that the gazillion itty-bitty cell analogy is not
quite accurate. Those cells can experience a rise in
source impedance while still offering their original
energy capability.
This battery as-new will deliver 9V at over 800A for
15 seconds. This suggests a source impedance of
(12-9)/800 = .004 ohms. It now produces about 300A
so the new source impedance is (12-9)/300 = .010
ohms.
So while the impedance has doubled, the available
energy at 6A loading has been barely affected . . . if
at all. A rise from .004 to .010 ohms source impedance
has little influence on a test load of (12/6)= 2 Ohms.
This argues with any analogy that suggests a "dead"
micro-cell in a battery becomes totally disconnected
from the array. It suggests that individual cells
can demonstrate an ability to store and regurgitate
energy while experiencing an independent and unrelated
rise in source impedance.
This discovery suggests that it is possible for a
battery to meet battery-only-ops requirements while
demonstrating reduced cranking performance. This ol'
dog is still learning . . . and my grey haired bench
test battery is still in service.
Bob . . .
Message 5
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I like some of the accessory connectors like the auto-fuse adapter.
They look nice, but for semi-reusable, manually applied connectors, can they really
be better than a regular wirenut? Wirenuts have fallen out of fashion, but
they are extremely reliable and have their own strain relief. Some come pre-gooped
for water-tightness.
I have been looking into replacing my products' Fastons and crimp terminals with
cage clamps and am especially interested in the lever-operated cage clamps.
Ultra-reliable and simple to use.
In this post-fiberoptic world, maybe NO connectors are the best way to go for data.
Vehicles just put data on the powerlines, and various wireless protocols
are taking the place of a whole lot of wire in advanced designs. Hey, NO connectors!
Would you trust your elevator trim to Bluetooth or Zig-Bee? I am starting to think
this is the way it's going.
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones@charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=356265#356265
Message 6
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Subject: | Re: Canopy Switch |
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
Nuckolls, III
Sent: Friday, October 28, 2011 1:20 PM
Subject: Re: AeroElectric-List: Re: Canopy Switch
--> <nuckolls.bob@aeroelectric.com>
At 12:00 PM 10/28/2011, you wrote:
><mdnanwelch7@hotmail.com>
>
>Jeff, Bob N, Joe, everyone else,
>
> If someone isn't crazy about the mechanical "open/closed switch"
> in the circuit, would it
>be a better (as in more robust) idea to have an optical switch? A
>simple tab on the canopy, properly positioned, could open/close an
>optical switch as needed.
>
> Just wondering.......
Another option is a reed-switch operated by a magnet.
Bob . . .
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