Today's Message Index:
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1. 05:25 AM - DISCONNECTING BATTERY WHILE ENGINE IS RUNNING (racerjerry)
2. 07:50 AM - Re: DISCONNECTING BATTERY WHILE ENGINE IS RUNNING (Robert L. Nuckolls, III)
3. 08:07 AM - Re: 24x7diy LED noise experiment (update) (Robert L. Nuckolls, III)
4. 08:12 AM - Re: 24x7diy LED noise experiment (update) (Jeff Page)
5. 08:22 AM - Re: WigWag's resistors for HID circuit (Robert L. Nuckolls, III)
6. 10:09 AM - Re: WigWag's resistors for HID circuit (hotwheels)
7. 10:49 AM - Re: Re: WigWag's resistors for HID circuit (B Tomm)
8. 11:57 AM - Re: WigWag's resistors for HID circuit (hotwheels)
9. 01:44 PM - Re: Re: WigWag's resistors for HID circuit (Robert L. Nuckolls, III)
10. 11:36 PM - Re: 24x7diy LED noise experiment (update) (Holger Selover-Stephan)
Message 1
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Subject: | DISCONNECTING BATTERY WHILE ENGINE IS RUNNING |
QUOTE: I've verified this both on cars and airplanes where disconnection of the
battery while the alternator is running produces a only a small rise in bus noise.
WOW With an alternator system (as opposed to generator), I would be very afraid
to disconnect the battery while the engine is running. Many years ago, while
doing an operational check on a piece of aircraft ground equipment (cargo loader),
the battery became disconnected (corrosion/looseness) from the alternator
charging system and apparently the alternator voltage increased to many times
its normal output and immediately burned out every light bulb on the vehicle.
I was about 50 feet away at that time and I will never forget hearing the
engine bog down and turning around to see all the vehicles flood lights going
off like flashbulbs.
This source claims that such problems occur regularly but not all of the time: http://www.troubleshooters.com/dont_disconnect_battery.htm
I only had to replace light bulbs. With all the modern electronics in newer cars
and airplanes, I shudder to think of the costs involved should a similar event
occur today.
This was a very early alternator system with an external regulator; Ford, I believe
(although it could have been a Chrysler system). Has something changed where
disconnection of a battery from an alternator charging system is no longer
as dangerous?
--------
Jerry King
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=396145#396145
Message 2
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Subject: | Re: DISCONNECTING BATTERY WHILE ENGINE IS RUNNING |
At 07:24 AM 3/13/2013, you wrote:
QUOTE: I've verified this both on cars and airplanes where
disconnection of the battery while the alternator is running produces
a only a small rise in bus noise.
WOW. With an alternator system (as opposed to generator), I would be
very afraid to disconnect the battery while the engine is running.
Alternator performance sans battery is a function
of regulator design. Indeed, there have been
instances of poor regulator design but
I suspect that those are pretty much a thing
of the distant past.
Consider that alternators are manufactured
by the millions per year and intended for
service in very uncontrolled situations.
Situations that must include inadvertent
disconnection of the battery. Folks who
supply such products would be well advised
to consider this possibility in their
product development design goals.
In fact, modern regulator design specs call
for ability to withstand worst case load
dumps (sudden disconnection of battery
and system demands while heavily loaded).
In the current chapter on alternators, I
describe a demonstration I witnessed at
the Motor Car Parts of America development
labs a few years back. I watched a technician
disconnect a heavily loaded alternator's
b-lead 5 times in a row. The flash of light
from the arc precluded taking any video
of the event. I tried two times. I wish
I had 'scope traces for the b-terminal
voltage. The energy release was impressive!
The alternator's regulator took it all in
stride and continued to function after 5
trials by lighting.
The Bonanza has allowed battery-off,
alternator-only ops ever since I can remember.
I did the regulator design for the pad-
driven standby generator about 1979. Beech
liked the design and asked for an alternator version
too. The specification control drawing
required a well behaved alternator without
battery. Those alternators had enough retentivity
in the field-pole material to self excite. So
another feature of the regulator's
specification control drawing called for
the regulator to come-alive and bring
the alternator on line with just a couple
of volts of residual output from an un-excited
alternator.
I don't think the Bonanza (and probably Barons)
ever had the functional equivalent of the
split-rocker master switch designed to preclude
alternator-only operations. The only conversations
I recall at Cessna during the split-rocker
evolution was a concern about making sure
the alternator had battery voltage to come
on line . . . I don't think anyone was concerned
about alternator-only ops being problematic
but the split-rocker thing made it unnecessary
to even consider it.
There's an interesting story about that
self-excitation thing. About 15 years ago,
Beech receiving inspection rejected a batch
of new alternators for failure to self-excite.
This brought a lot of consternated alternator
sales and engineering folks to Beech to see
what all the fuss was about.
It seems that the self-excitation feature
for these machines was never a documented
requirement or design goal. They just happened
to work that way. So for 20+ years, Beech
was writing specs to exploit the feature.
At the same time, the alternator guys were
unaware of Beech's expectations that self-
excitation be consistently demonstrable.
Hence their surprise when purchasing sent them
a 'ding letter' complaining about failure
to demonstrate self-excitation during receiving
inspection.
I don't know what was ultimately done to
renew the flow of alternators to the Bonanza
and Baron lines but I'm sure they worked it
out!
In retrospect, I'm pretty sure the designs we
were producing back then would not withstand the load-dump
test I described above. There was no requirement
to demonstrate it. I wonder if it has been added
since. I'll have to ask.
Bob . . .
Message 3
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Subject: | Re: 24x7diy LED noise experiment (update) |
At 11:24 PM 3/12/2013, you wrote:
><holger-d@shadowbrush.com>
>
>OK, fair enough. My investment is time while waiting for another
>report from you, and some $150 for the lights. Should I, and maybe
>others, contribute to expenses of this experiment? Having an
>off-the-shelf, sub $200 landing light pair should be of interest to
>a few others as well. And yes, no guarantee for noise levels.
I don't think there's much value in waiting
for me or anyone else to put a band-aid on
any particular COTS offering for lights.
That market is evolving very rapidly and as
OBAM aviation participants, limiting our
selection of products to those which have
be successfully 'bandaged' is counter-productive.
I think I've written on these pages numerous
times that I've never encountered a noise
problem that couldn't be whipped. With that
assertion in mind, I would encourage folks
to try anything that floats their boat. If
it produces light sufficient to your needs
then let's tackle noise problems as a separate
issue.
Dollars is not the limiting factor for my
efforts, it's time. Further, the time thing
is more involved than having a clear bench
or wrestling with procurement delays. The
elegant solution has to be tempered against
the tools I have to produce it along with
trading out assembly methods and techniques.
I can tell you that what I'm carving on now
for the 24x7diy assemblies is in its third
generation.
The risk is that once the elegant solution
for 24x7diy is achieved, they might go out
of business or something better might come
along. That's the down-side of OBAM aviation.
Things done on the TC side of the house tend
to become carved in stone. Some of my designs
at Electro-Mech are still in production after 30
years. Many of those out of production were
canned because critical components are not made
any more!
Things we do in OBAM aviation are more likely
to be pushed overboard because something better
came along, not because critical parts have
reached end of market life. It's a different
ball game entirely.
So I would advise you to search out and
try lighting products that meet your design
goals . . . let's whip what ever noise issues
arise later.
Bob . . .
Message 4
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Subject: | Re: 24x7diy LED noise experiment (update) |
> It occurs to me that we could do a HID version
> of this flasher that automatically forces a
> one-minute warm up period before allowing wig-wag
> operations to commence.
XeVision has a patent on the "technique" of delaying flashing until
the lamps have warmed up.
http://xevision.com/hid_pulsing.html
Many of their ballasts have a control input that allows flashing
without switching the power to the ballast.
Jeff Page
Dream Aircraft Tundra #10
Message 5
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Subject: | WigWag's resistors for HID circuit |
At 01:21 AM 3/13/2013, you wrote:
Bob,
I had not considered a spike coming back from the input of the ballast.
Could flashing the HID's (properly pre-heated or not) damage other
electronic equipment onboard the typical aircraft, ie expensive radios and
Nav stuff?
No. The 'spike' would be an artifact of
inductive features in the design of the ballast.
Just as the spike suppression diode across
a contactor coil protects the controlling
switch, I suspect that similar measures
for interfacing a solid state flasher with
HID ballasts has a similar makeup. The
risks are limited to the controlling device;
FETS in the controller or in the case of
battery contactors, the master switch.
The worry that such spikes represent any hazard
to the rest of the system is a myth borne out
of misunderstanding nonetheless widely circulated.
I would like to try the flasher from B and C.
Can you point me to a source for suitable resistors?
http://tinyurl.com/a62m9mx
Check with local electronics suppliers too. This
is not a rare part. 75 ohms, 5W, wire wound.
Depending on your installation, you might find
these more attractive. They have mounting ears.
http://tinyurl.com/akqxrd7
I look forward to the results of your experimentation with the HIDs.
Keep in mind that you should operate your
lamps continuously for about a minute before
you revert to wig-wag mode.
Bob . . .
Message 6
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Subject: | Re: WigWag's resistors for HID circuit |
Hi,
I have two 55w HID landing lights (P/N MR16) sourced from rigidindustries.com and
the "low-tech" flasher obtained from B&C. I was only able to get flashing going
by using the load resistors (from ebay). Works great so long as you give
the HIDs adequate warm up time.
Cheers,
Jay
N433RV RV-10
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=396186#396186
Attachments:
http://forums.matronics.com//files/wig_wag_606.pdf
Message 7
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Subject: | Re: WigWag's resistors for HID circuit |
Jay,
The website you site doesn't show HID, only LED. Can you confirm which HID
your have, and approximately how many hours of run time with the flasher so
far?
Thanks
Bevan
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of hotwheels
Sent: Wednesday, March 13, 2013 10:03 AM
Subject: AeroElectric-List: Re: WigWag's resistors for HID circuit
--> <jaybrinkmeyer@yahoo.com>
Hi,
I have two 55w HID landing lights (P/N MR16) sourced from
rigidindustries.com and the "low-tech" flasher obtained from B&C. I was only
able to get flashing going by using the load resistors (from ebay). Works
great so long as you give the HIDs adequate warm up time.
Cheers,
Jay
N433RV RV-10
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=396186#396186
Attachments:
http://forums.matronics.com//files/wig_wag_606.pdf
Message 8
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Subject: | Re: WigWag's resistors for HID circuit |
They may have discontinued HID sales, and the name changed since I purchased...
Used to be planelights.com. I've been running them for
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=396202#396202
Message 9
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Subject: | Re: WigWag's resistors for HID circuit |
At 12:03 PM 3/13/2013, you wrote:
>
>Hi,
>
>I have two 55w HID landing lights (P/N MR16) sourced from
>rigidindustries.com and the "low-tech" flasher obtained from B&C. I
>was only able to get flashing going by using the load resistors
>(from ebay). Works great so long as you give the HIDs adequate warm up time.
Good information! Thanks for sharing.
Bob . . .
Message 10
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Subject: | Re: 24x7diy LED noise experiment (update) |
On Mar 13, 2013, at 8:06 AM, Robert L. Nuckolls, III wrote:
> I don't think there's much value in waiting
> for me or anyone else to put a band-aid on
> any particular COTS offering for lights.
> That market is evolving very rapidly and as
> OBAM aviation participants, limiting our
> selection of products to those which have
> be successfully 'bandaged' is counter-productive.
OK, understood, Bob. If it's that much of a moving target. I'll pipe up again when
I have the lights and checked for noise.
Very much appreciate the time you took to explain the situation.
Thanks,
Holger
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