Today's Message Index:
----------------------
1. 02:03 AM - Re: Encoder / Transponder domino failure? (Neville Kilford)
2. 04:40 AM - Re: Re: Battery Contactor vibration problem (William Slaughter)
3. 06:27 AM - Re: Encoder / Transponder domino failure? (SportAV8R@aol.com)
4. 06:34 AM - Re: Dimmers (Jim Sower)
5. 06:59 AM - Re: Re: Dimmers (Robinson, Chad)
6. 07:13 AM - Re: Re: Battery Contactor vibration problem (Robert L. Nuckolls, III)
7. 07:16 AM - Re: Dimmers (John Slade)
8. 07:19 AM - Re: Small aux battery: diode vs. relay (Robert L. Nuckolls, III)
9. 07:33 AM - Re: Dimmers (Robert L. Nuckolls, III)
10. 07:35 AM - Re: Re: Dimmers (Robert L. Nuckolls, III)
11. 07:43 AM - LOM-magneto filters (Klaus Dietrich)
12. 08:00 AM - Re: LOM-magneto filters (Robert L. Nuckolls, III)
13. 08:00 AM - Hobbyair Respirator For Sale (Gabe A Ferrer)
14. 08:00 AM - Re: Dimmers (Robert L. Nuckolls, III)
15. 08:04 AM - Re: Re: Dimmers (Robert L. Nuckolls, III)
16. 08:04 AM - Re: Re: Battery Contactor vibration problem (Robert L. Nuckolls, III)
17. 08:05 AM - Re: Source for BNC adapters? (Robert L. Nuckolls, III)
18. 08:06 AM - Re: Dimmers (Eric M. Jones)
19. 08:21 AM - Re: Dimmers (Bob Kuc)
20. 08:32 AM - Re: Re: Battery Contactor vibration problem (Vince Ackerman)
21. 08:55 AM - Re: Dimmers (Stucklen, Frederic IFC)
22. 10:35 AM - Re: Re: Dimmers -- and LED trends (Canyon)
23. 10:42 AM - Re: Bob, external power receptacle (Robert L. Nuckolls, III)
24. 11:09 AM - Re: Source for BNC adapters? (HCRV6@aol.com)
25. 11:51 AM - Re: Re: Battery Contactor vibration problem (Robert L. Nuckolls, III)
26. 12:11 PM - Re: Dimmers (Robert L. Nuckolls, III)
27. 12:52 PM - Re: Dimmers (John Schroeder)
28. 01:16 PM - Re: Dimmers -- and LED trends (Eric M. Jones)
29. 02:12 PM - Re: Track width on PCB (Gilles.Thesee)
30. 02:36 PM - Magnetos and preflight testing . . . (Robert L. Nuckolls, III)
31. 02:50 PM - Re: Dimmers (Bob Kuc)
32. 03:37 PM - Re: Dimmers (plaurence@the-beach.net)
33. 04:41 PM - Re: Re: Dimmers -- and LED trends (Canyon)
34. 05:09 PM - Re: Re: Dimmers -- and LED trends (John Schroeder)
35. 05:33 PM - Re: Re: LED Position Lights (Dawson, Bill)
36. 06:07 PM - Re: Dimmers (John R)
37. 06:10 PM - B&C regulator for sale (Bob Bittner)
38. 06:20 PM - Re: Re: Dimmers -- and LED trends (Canyon)
39. 08:50 PM - Re: Dimmers (Jim Sower)
40. 09:20 PM - Re: Dimmers (Robinson, Chad)
41. 09:41 PM - Re: Dimmers (Jim Sower)
42. 11:40 PM - Re: Dimmers (John R)
Message 1
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| Subject: | Re: Encoder / Transponder domino failure? |
--> AeroElectric-List message posted by: "Neville Kilford" <nkilford@etravel.org>
Bill,
Have you run the transponder without the encoder? I.e. is it really the
transponder that's at fault, or just some "interference" sort of problem
that's caused by the encoder?
Nev
--
Jodel D150 in progress
UK
----- Original Message -----
From: <SportAV8R@aol.com>
Subject: AeroElectric-List: Encoder / Transponder domino failure?
> --> AeroElectric-List message posted by: SportAV8R@aol.com
>
> Okay, gentlemen: help me puzzle this out...
>
> A few weeks ago my RMI microEncoder became erratic in flight, cycling into
test mode and shutting itself off repeatedly. Finished the flight with no
mode C squawk but a normally-functioning transponder; at least I was seeing
the interrogation light come on at the expected level of activity. Tear-down
inspection of the RMI revealed a rattle in the case, turned out that two
screws holding down a heat sink had shed their nuts and lockwashers and
fallen free. The screws were in the bottom of the can, but the nuts and
washers had been dancing around on the solder-side of the lower circuit
board, apparently causing the gremlin-action in flight.
>
> The screw integrity issue seems to have come from the insulating shoulder
washers compressing/separating into sheared-off fragments and exhausting
their pre-load on the fasteners, which then vibrated loose. It was a simple
fix (Loc-Tite) and the bullet-proof uEncoder came back to life and has acted
fine since.
>
> Later on, my buddy says he can't see me on his TCAD, and I start to notice
the interrogation light is not doing anything on the next few local flights.
That's odd; I usually get pinged at this altitude at the home field. A
cross-country trip just outside some major Class C confirms that the Garmin
GTX 320 is apparently deaf or mute, and we have a problem.
>
> Dilemma: garmin will bench test it for me and fix it for $250. Cost is
the same even if the unit checks out okay. I know from the startup light
that it has power. How can I be sure it's not a coincidental
feedline/antenna problem without spending 250 bucks?
>
> All I can speculate is that somehow during all the electrical mayhem in the
encoder while the screws were loose, some voltage got into the XPDR via the
data bus from the encoder and let the smoke out of some component. It seems
unlikely that a stray voltage on those pins would damage the very guts of the
transponder rather than just the mode C part, but I'm just musing in the
dark.
>
> Ideas appreciated.
>
> I know of a nearby avionics shop that might be willing I will probably
give them a call tomorrow.
>
> -Bill B
> RV-6A
>
>
Message 2
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| Subject: | Re: Battery Contactor vibration problem |
--> AeroElectric-List message posted by: "William Slaughter" <willslau@alumni.rice.edu>
I'm powering my Aerosance FADEC system directly from the battery busses
via fusible links - no contactor involved.
William Slaughter
RV-8 IOF-360
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Vince
Ackerman
Subject: Re: AeroElectric-List: Re: Battery Contactor vibration problem
--> AeroElectric-List message posted by: Vince Ackerman <vack@mac.com>
I glad (sort of ) that it wasn't just me and you could duplicate what I
did with a little more eloquence. The bottom line for an aircraft
(helicopter ) like mine, with FADEC's that cannot tolerate any power
interuptions, is still a question in my mind. What are the options?
Give a vibration that could disrupt the contactor, what could bridge
the millisecond power interuptions that would keep the computers from
shutting down and rebooting? Some sort of capacitor? A rubber mount for
the contactor? I'm not an electrical engineer by any stretch, so your
suggestions would be most valuable.
Thanks
Vince
On Monday, October 20, 2003, at 02:19 PM, Robert L. Nuckolls, III wrote:
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> <bob.nuckolls@cox.net>
>
>
> Yes. Went to the workbench and wired up your Cole-Hersee
> contactor to a power supply and load resistor. Powered
> it up at 10V and 15V. Lightly tapped with a
> hammer and took the following response graphs:
>
> http://www.aeroelectric.com/temp/CH10V.jpg
> http://www.aeroelectric.com/temp/CH15V.jpg
>
>
> Dug out a RBM/Stancor part and repeated the experiment:
>
> http://www.aeroelectric.com/temp/RS15V.jpg
> http://www.aeroelectric.com/temp/RS10V.jpg
>
> Both brands of contactor are similarly affected
> by the hammer taps.
>
> After some reflection, I'm not surprised. While
> relatively light taps were used, a rigid metal
> mass striking another rigid metal mass can easily
> generate acceleration pulses (shock)
> of 100-1000G . . . The pulses are very short
> meaning that the energy transferred is low . . .
> but instantaneous force to components mounted
> within can be substantial.
>
> Forgive the non-quantified words above like "light"
> "short" "substantial" and "low" . . . I don't have
> the tools in my shop to instrument and quantify
> these phenomenon. However, I will invoke some hands-
> on experience with qualifying flight hardware at
> shock levels of 400G or more . . . it's NOT difficult
> to impart stimulus of 100 to 1000G in these situations.
>
> You'll note that documented disruptions are on the order
> of 1 to 3 milliseconds in length and steep sided.
> The steep sides says there was no arc forming in the
> contact gaps. You will also note that each event
> generated 2 to 5 circuit interruptions (contact bounce).
>
> Playing with the test fixture demonstrated that the
> number of interruptions per event had more to do with
> tapping-technique and chance than with any observable
> difference between the two brands of contactor.
>
> Okay, what's this all mean?
>
> (1) let us note that both contactor designs are
> at least 50 years old and no doubt been produced in
> millions of parts. If the parts are still in production,
> it's a fair assumption that the vast majority of
> users have experienced satisfactory service life
> WHETHER OR NOT they were aware of the propensity for
> bouncing contacts if tapped with a hammer.
>
> (2) the stimulus is not cyclical vibration but short,
> high-g shocks . . . a stimulus rarely found in an
> airframe or any other vehicle.
>
> (3) Interruptions of 3 millisecond interruptions and
> more are EXACTLY the kinds of power input perturbations
> that DO-160 tells us to EXPECT and be prepared to
> shrug it off.
>
> (4) the act of rotating the mounting axis of a contactor
> to ward off evil shocking spirits is not useful
> . . . aerodynamic linear g-loads can be reasonably
> expected to maximize through the vertical axis . . .
> mechanical shock may come from any direction.
>
> Bottom line:
>
> If you hammer-tap any contactor of this genre, you'll
> undoubtedly produce the same kind of interruptions
> that Vince noted and brought to our attention. I'm
> pleased to have an opportunity to compare two
> brands of similar devices and to have a reason to sit
> down and consider their relative design features.
> It's useful to make a new discovery of old data and
> understand its significance in the design and operation
> of our airplanes.
>
> What I've learned today doesn't change my recommendations
> for using these el-cheapo contactors in a well-considered,
> failure-tolerant design. I continue to be of the opinion
> that they will give good value performance free of extraordinary
> risk when mounted in any orientation for ease of installation.
>
>
>> Thanks again
>>
>> Vince
>
> Thank you sir! I figure any day you go to bed knowing
> something you didn't know yesterday is a good day. This
> would not have come to light without your observations
> and a willingness to ask the question.
>
> I cranked though a number of plausible but way-out-in-left-
> field scenarios to explain what you observed. It was quite
> useful to put all those hypotheses in the trash and
> discover the truth . . . and best yet . . . to find that
> it didn't matter!
>
> Bob . . .
>
==
direct advertising on the Matronics Forums.
==
==
==
Message 3
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| Subject: | Re: Encoder / Transponder domino failure? |
--> AeroElectric-List message posted by: SportAV8R@aol.com
In a message dated 10/21/2003 5:03:33 AM Eastern Daylight Time, nkilford@etravel.org
writes:
> Bill,
>
> Have you run the transponder without the encoder? I.e. is it really the
> transponder that's at fault, or just some "interference"
> sort of problem
> that's caused by the encoder?
>
> Nev
No, but that would be easy to accomplish. I will put it on my list of things to
try.
Message 4
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--> AeroElectric-List message posted by: Jim Sower <canarder@frontiernet.net>
I was thinking about using largish LEDs mounted under the glare shield to
shine on my panel. Someone told me that there are dimmers that are actually
oscillators that vary the width of the "ON" pulse to "dim" LEDs. Is there
anything to this? Are these devices readily available? Are they compact
enough to compete with pots for compactness?
Inquiring minds need to know .... Jim S.
Message 5
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--> AeroElectric-List message posted by: "Robinson, Chad" <crobinson@rfgonline.com>
> Is there a solid state dimmer available yet that only uses
> the power needed to light the bulbs without spilling over
> excess as heat?
I don't know of any for the aircraft industry, but they're not hard to build on
a piece of perfboard. They're called "switching" or "switch mode" power supplies.
They're also much more efficient - linear regulators dissipate any excess
power as heat, so you use the same amount of power (plus a small margin) as you
would have used at full brightness. Switching regulators only have that little
margin, so at maximum dim you're using very little power.
For instance, Maxim's MAX8545 is $0.92 in bulk (probably a little over a buck in
single-unit quantities), and have a 2.7V-28V input range. The first page of
their spec sheet has a sample application circuit that you could probably put
on a perfboard in an afternoon's work, if you know how to read a schematic. It's
got about 10 parts, which is more than the linear regulator, but if you were
building it yourself you'd probably still end up saving money.
They are NOT a panacea, however. Switch-mode regulators work by running an oscillator,
which can put out noise that causes all sorts of trouble with other devices.
You can eliminate much of this noise by putting the circuit in a shielded
enclosure, if you're careful. The problem is that "switching artifacts" (more
noise) can still appear on the output, so all those wires to your lights can
act like antennae and radiate that noise. It's possible to eliminate even this
with a good choke design, but that's not exactly a beginner design - you would
need to tune it for the 300kHz switching frequency and possibly a few harmonics.
All things considered, I'd stick with a linear design like B&C's unless you have
a good reason to switch. Heat is an easier problem to deal with than noise.
Regards,
Chad
Message 6
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| Subject: | Re: Battery Contactor vibration problem |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:26 PM 10/20/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: Vince Ackerman <vack@mac.com>
>
>I glad (sort of ) that it wasn't just me and you could duplicate what I
>did with a little more eloquence. The bottom line for an aircraft
>(helicopter ) like mine, with FADEC's that cannot tolerate any power
>interuptions, is still a question in my mind. What are the options?
>Give a vibration that could disrupt the contactor,
There's a big difference between vibration and shock in terms
of intensity and total energy of the stimulus. You're not
going to see this interruption happen in normal operation
even in a helicopter . . . now, if you hit the side of a
mountain . . .
> what could bridge
>the millisecond power interuptions that would keep the computers from
>shutting down and rebooting? Some sort of capacitor? A rubber mount for
>the contactor? I'm not an electrical engineer by any stretch, so your
>suggestions would be most valuable.
ANY accessory needed for engine operation should run
from a battery bus . . . and ESPECIALLY when the accessory is
known to be ill-prepared to live in the real world of
aircraft. If Rotorway has told you their FADEC is so
afflicted, then this reinforces my not so humble opinion
of their power distribution architecture.
Bob . . .
Message 7
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--> AeroElectric-List message posted by: "John Slade" <sladerj@bellsouth.net>
Jim,
I have the solid state unit from B&C. The one that comes with the goose neck
light. It's small and dims 4 or 5 outputs. Works well with LEDS, not
expensive, and much easier than making one.
John Slade
Message 8
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| Subject: | Re: Small aux battery: diode vs. relay |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:07 PM 10/20/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: Geoff Evans
><hellothaimassage@yahoo.com>
>
>Bob.
>
>After reading this list for a year or so and perusing the archives, I've
>narrowed down my my proposed electrical system from a "that would be nice to
>have" design to a "this is all I really need to get the job done" design.
>
>I'm (now) planning dual electronic ignitions, one main battery, and one small
>aux battery which ONLY supports the second ignition and is not used for
>starting. I might install a SD-8 later, but I don't think I need that for my
>VFR ship at this time.
>
>Anyway... You made a comment in one of the archived messages that you prefer
>"hard" connections to diodes in this situation. Why is that??
>
>I'm trying to decide between a S704-1 relay with manual control of the small
>aux battery bus tie, or a schottky diode to provide current for charging of
>the aux battery and operation of the second ignition.
>
>The diode is attractive because it reduces the possibility of pilot error
>(like cranking the engine with the aux battery connected) and it reduces the
>parts count. However, the relay is attractive because it gives you more
>control over the system and doesn't produce the voltage drop that a diode
>would. So... Why do you prefer "hard" connections to diodes?
because you can charge and load the battery thought the same path
and both batteries are always charged at the same bus voltage . .
>Also... I understand that small aux batteries won't accept a large charging
>current, so fat wires are not necessary. You have stated in the past that 18
>or 20 AWG wire is fine for charging only a small aux battery and running one
>ignition. However, how does one KNOW for sure how much charging current the
>small (4.5 AH) battery will accept? The distance between my batteries and
>their relays/contactors is less than 6", so I don't plan to protect those
>wires. How do I know that I won't smoke the wire going to the aux battery if
>(for some strange reason) it is accepting a large charge?
You won't smoke any wires with a battery that small. The only
time the battery would request a high charge rate is if you
ran it down. If it's tied to the main battery with a diode, you
can't run it down unless the main battery is going down too and
or has disappeared. Which begs the question, if you choose not
to provide for complete isolation of the two batteries via hard
contacts, then what scenario do you anticipate that the small
battery would become your last ditch option for plugging the
hole in dike?
Bob . . .
Message 9
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:14 PM 10/20/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Robinson, Chad"
><crobinson@rfgonline.com>
>
>In case nobody else responds, you can make some guesses if you squint hard
>at the fourth-to-last picture here:
> http://www.rvproject.com/20030505.html
>
>Looks like a pot controlling a single, heat-sunk TO-220 package device
>with only a few other components on the board. I'm guessing an LM317?
>
>B&C's site has a picture of their dimmer, which doesn't look like much
>more, but it's a heck of a big heat sink. Also, it includes some DB-9
>connectors that add to the parts count but makes it easier to hook up, and
>the mounting tabs look a lot easier to work with. Bob, do you know where
>they sourced this heat sink? Looks like a nice getup.
That's the series of dimmers I designed and use to sell off
my website. There are a series of dimmers rated at .5A, 1.5A
3A and 5A. All are electrically identical except for the size
of the heatsink and the linear regulators (lm317, lm350, lm338).
If Van's dimmer doesn't have a heatsink and it features a
linear regulator of the LM317 variety, then it's NOT a 1.5A
capable device. The LM317 will control this load only when
mounted on a suitable heatsink.
The heatsinks I used can be found in the Wakefield Engineering
catalog at:
http://www.wakefield.com/pdf/extruded_heat_sink.pdf
The smaller heatsink is a 401K, the larger is a 403K
>I see B&C also offers a 5A option, which will control a heck of a lot more
>lights - no way will that itty bitty heat sink picture on this Van's
>builder's site stand up to even a portion of that without torching the
>board, unless this picture isn't of the right thing.
The 5A controller has been used mostly for heater motor
controls in airplanes with hot-water heaters.
>The TO-3 picture in even the smaller of B&C's site can better dissipate
>heat to begin with (over the TO-220 package), so I'm certain it will stand
>up to the load it says it will. But that setup I see pictured on this
>Van's builder's site won't take more than 500mA or so unless there's a fan
>blowing on it - that will limit the number of lights it can control. (Read
>as 1/3 as many lights, if that. And don't plan on touching it.)
I believe you are correct . . .
>Bear in mind that linear regulators, which these all are, just convert the
>excess voltage to heat, so the DIMMER your lights are the HOTTER they get
>(some people find this counter-intuitive). That means that if you hardly
>dim your lights you may never notice the difference, until you turn them
>way down one day and the dimmer torches anything that might be touching it.
For the most part, the LM317 will self protect by shutting down
if they get too hot . . . so if you overload Van's dimmer, it might
survive the ordeal. But it's not a 1.5A rated device.
> > -----Original Message-----
> > From: Robert L. Nuckolls, III [mailto:bob.nuckolls@cox.net]
> > Sent: Monday, October 20, 2003 6:49 PM
> > To: aeroelectric-list@matronics.com
> > Subject: Re: AeroElectric-List: Dimmers
> >
> >
> > --> AeroElectric-List message posted by: "Robert L. Nuckolls,
> > III" <bob.nuckolls@cox.net>
> >
> > At 11:17 AM 10/20/2003 -0700, you wrote:
> > >--> AeroElectric-List message posted by: Geoff Evans
> > ><hellothaimassage@yahoo.com>
> > >
> > >Can anyone compare and contrast the panel lighting dimmer
> > listed in Vans
> > >catalog with the dimmer offered by B&C?
> > >
> > >Both appear to good for 1.5A, but the Vans dimmer is less
> > than half the cost
> > >of the B&C dimmer. I know you get what you pay for, but I'd
> > like to know what
> > >the differences are. There is no picture in the Vans
> > catalog, so I'm not
> > >really too sure what they're offering.
> >
> > I am unfamiliar with Van's offering. Can anyone help Geoff out here?
> >
> > Bob . . .
> >
> >
> > ============
> > ============
>
>
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
Message 10
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 02:00 AM 10/21/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: <mjheinen@adelphia.net>
>
>Is there a solid state dimmer available yet that only uses the power
>needed to light the bulbs without spilling over excess as heat?
Sure, a number of articles have been published (most notably by
Jim Wier in Kitplanes) on variable duty-cycle controllers
for panel lights. Another way to mitigate heat issues is
to reduce power needed . . . e.g. all LED illumination.
Bob . . .
Message 11
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| Subject: | LOM-magneto filters |
--> AeroElectric-List message posted by: Klaus Dietrich <Klaus.Dietrich@oracle.com>
I'm making the electrics on a LOM powered Bucker and I wonder what sort
of magneto filters (if any) I should use. Can't get hold of the LOM
filters as specified on Bob's drawing for the LOM.
I bought 2 USmade Magneto Filters from Lonestar (Spruce), just to find
out that there is no reasonable way to mount them on the LOM magnetos.
Best I could imagine is to mount them on the firewall, which is 60 cm
away from the mags; don't know if this makes any sense
I changed the LOM generator and use the TK10 Alternator plus OV from B&C
instead.
Thanks for any advise on this one
Klaus, Vienna
Message 12
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| Subject: | Re: LOM-magneto filters |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 04:43 PM 10/21/2003 +0200, you wrote:
>--> AeroElectric-List message posted by: Klaus Dietrich
><Klaus.Dietrich@oracle.com>
>
>I'm making the electrics on a LOM powered Bucker and I wonder what sort
>of magneto filters (if any) I should use. Can't get hold of the LOM
>filters as specified on Bob's drawing for the LOM.
>I bought 2 USmade Magneto Filters from Lonestar (Spruce), just to find
>out that there is no reasonable way to mount them on the LOM magnetos.
>Best I could imagine is to mount them on the firewall, which is 60 cm
>away from the mags; don't know if this makes any sense
>
>I changed the LOM generator and use the TK10 Alternator plus OV from B&C
>instead.
>
>Thanks for any advise on this one
>Klaus, Vienna
First, leave them off entirely and see if they're really
necessary. If you wire the p-leads according to the power
distribution diagram, it's likely that the filters will
not be needed. I included them only because they're called
out on LOM's drawings. I'm not sure they even knew how the
filters worked and when they are useful.
Bob . . .
Message 13
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| Subject: | Hobbyair Respirator For Sale |
--> AeroElectric-List message posted by: "Gabe A Ferrer" <ferrergm@bellsouth.net>
Hobbyair Buddy System with 2 Direct Feed Hoods #HBBUDDF
40 Foot Hose for Hobbyair
Will sell for $280 plus shipping. Paid $561. Used about seven times. Mostly for
priming a few parts.
Please contact me off list if interested
Gabe A Ferrer
RV6 N2GX 72 hours
South Florida
Email: ferrergm@bellsouth.net
Cell: 561 758 8894
Night Phone: 561 622 0960
Fax: 561 622 0960
Message 14
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 10:16 AM 10/21/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "John Slade" <sladerj@bellsouth.net>
>
>Jim,
>I have the solid state unit from B&C. The one that comes with the goose neck
>light. It's small and dims 4 or 5 outputs. Works well with LEDS, not
>expensive, and much easier than making one.
>John Slade
That's the 0.5A version. Exactly the same electronics as
all other sizes, just no heatsink. This is an approximate
equal to Van's sink-less product.
Bob . . .
Message 15
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:59 AM 10/21/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Robinson, Chad"
><crobinson@rfgonline.com>
>
> > Is there a solid state dimmer available yet that only uses
> > the power needed to light the bulbs without spilling over
> > excess as heat?
>
>I don't know of any for the aircraft industry, but they're not hard to
>build on a piece of perfboard. They're called "switching" or "switch mode"
>power supplies. They're also much more efficient - linear regulators
>dissipate any excess power as heat, so you use the same amount of power
>(plus a small margin) as you would have used at full brightness. Switching
>regulators only have that little margin, so at maximum dim you're using
>very little power.
>
>For instance, Maxim's MAX8545 is $0.92 in bulk (probably a little over a
>buck in single-unit quantities), and have a 2.7V-28V input range. The
>first page of their spec sheet has a sample application circuit that you
>could probably put on a perfboard in an afternoon's work, if you know how
>to read a schematic. It's got about 10 parts, which is more than the
>linear regulator, but if you were building it yourself you'd probably
>still end up saving money.
>
>They are NOT a panacea, however. Switch-mode regulators work by running an
>oscillator, which can put out noise that causes all sorts of trouble with
>other devices. You can eliminate much of this noise by putting the circuit
>in a shielded enclosure, if you're careful. The problem is that "switching
>artifacts" (more noise) can still appear on the output, so all those wires
>to your lights can act like antennae and radiate that noise. It's possible
>to eliminate even this with a good choke design, but that's not exactly a
>beginner design - you would need to tune it for the 300kHz switching
>frequency and possibly a few harmonics.
>
>All things considered, I'd stick with a linear design like B&C's unless
>you have a good reason to switch. Heat is an easier problem to deal with
>than noise.
Well considered advice sir . . . that's why the
offerings from AEC and now B&C are linears. I've
considered some switchmode regulator designs over
the years but haven't convinced myself that they're
good value yet . . . and with the lighting current
requirements going DOWN instead of up by using LEDs,
the switchmode dimmers may never make it to the
B&C catalog.
Bob . . .
Message 16
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| Subject: | Re: Battery Contactor vibration problem |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 06:39 AM 10/21/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: "William Slaughter"
><willslau@alumni.rice.edu>
>
>I'm powering my Aerosance FADEC system directly from the battery busses
>via fusible links - no contactor involved.
good for you . . .
Message 17
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| Subject: | Re: Source for BNC adapters? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 01:42 AM 10/21/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: HCRV6@aol.com
>
>Bob or anyone: Does anyone know of a source for the type of BNC adapter
>that Garmin uses in their new transponders and nav/com units (other than
>direct from Garmin that is). These are the type that install in the
>chassis with a
>snap ring and have a plug in socket on the inside to mate with the unit and a
>BNC jack on the outside.
>
>I want to replace the solder type antenna coax snap ring adapters that came
>with my KX-125. I called John Stark, but he said he has been looking for
>them
>also with no success so far.
I'm not familiar with this part. Got a picture?
Bob . . .
Message 18
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--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
Chad posted an excellent description of switching (PWM) type dimmers.
I would like to add that linear voltage regulators such as the LM317 (one of
those parts you really need to know about) give some great advantages over a
rheostat potentiometer in dimming applications.
Let's say you have a 15 Volt supply that you want to "dim" to 10V using a
rheostat. If the current is 1A that's 10W for the bulb and 5W dissipation in
the rheostat. Or you could just use a 5 ohm resistor if you are happy with
the 10W.
So why use a voltage regulator?
It's cheaper, smaller, lighter, and the output voltage won't noticeably
change if you add or subtract load or if the input voltage changes. You can
easily dump the heat where you want. You can remotely control it. You can
easily couple it electronically to other devices. It will outlast the
rheostat. A dozen other reasons....
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
Message 19
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--> AeroElectric-List message posted by: "Bob Kuc" <bkuc1@tampabay.rr.com>
Jim,
I am doing the same thing on my velocity. However, I put my largish LEDs in
the overhead console. I have three of them that light up the whole panel.
While I am not flying yet, I have sat in the garage with all the lights out
and it does light up the panel very nicely, but not that brightly. I am not
planning on putting a dimmer on. If you look at Jim Weir's site, he had an
article that used an op amp to oscillate to get a higher voltage through the
LEDs. I believe that the schematic did contain a pot for dimming it if
needed. You should be able to use that. The board should not be big at
all.
> I was thinking about using largish LEDs mounted under the glare shield to
> shine on my panel.
Bob
---
Message 20
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| Subject: | Re: Battery Contactor vibration problem |
--> AeroElectric-List message posted by: Vince Ackerman <vack@mac.com>
I guess I'll look into making a battery direct bus to run the Fadecs,
ign packs and fuel pumps, although it would be pretty much negating the
reason I put the contactor in there in the first place. Not much left
to be switched by a contactor. I wanted to be able to remove all power
from the aircraft busses, for several reason one of which was to try to
reduce electrolysis problems with the coolant and aluminum
block/radiator. On the plus side, leaving it as is, even if I lost the
contactor the alternator would still be providing power to the bus as
long as the engine was running. If it isn't , then I don't need them
anyway : ). How would I wire the battery bus / essential bus to be
powered by the alternator/battery in normal mode, powered by the
battery if the alternator died, and powered by the alternator alone if
the contactor failed? Guess I'll spend some time looking at appendix
Z. Wonder if there's a way to make a warning light that tells you the
contactor has failed (powered by the alternator)? I don't have a lot of
space on this thing to add components or modify the electrical system.
The electrical busses are contained in the overhead switch panel which
is only 12 x 8 inches.
Thanks for your ideas
Vince
On Tuesday, October 21, 2003, at 07:13 AM, Robert L. Nuckolls, III
wrote:
>
>
> There's a big difference between vibration and shock in terms
> of intensity and total energy of the stimulus. You're not
> going to see this interruption happen in normal operation
> even in a helicopter . . . now, if you hit the side of a
> mountain . . .
>
> ANY accessory needed for engine operation should run
> from a battery bus . . . and ESPECIALLY when the accessory is
> known to be ill-prepared to live in the real world of
> aircraft. If Rotorway has told you their FADEC is so
> afflicted, then this reinforces my not so humble opinion
> of their power distribution architecture.
>
> Bob . . .
>
Message 21
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--> AeroElectric-List message posted by: "Stucklen, Frederic IFC" <Fred.Stucklen@UTCFuelCells.com>
Listers,
I've tested and installed into my new RV-6A a digital dimmer from Carling
Technologies. It will easily switch 10A loads, has negligible heat output,
is small, and only has three wires (Power, Ground, & Output). Testing has
shown that they do not cause any radio interference.... The part number is
LD-3A1CC1-3AA-FE-1FC. The spec sheet can be found at:
http://www.carlingtech.com/pdf/ld_series.pdf
The Carling technologies website gives distributor names. I got mine as a
sample, but they should be in under $50.00 retail....
This was a nice find relative to constructing my own as I did in the last
RV. (Simple low frequency 555 timer circuit driving a MOSFET switch, with
controlled rise/fall times). The carling dimmer's waveforms were very
similar to what I had built, and the package is much smaller. The only
difference is that the Carling unit has 10 distinctive intensity setting,
while mine used a potentiometer.... Turns out to not be a big deal in the
cockpit......
I'm using two of these in a full IFR implementation......
Fred Stucklen
RV-6A N925RV 65 Hours
Subject: Re: Dimmers
From: Jim Daniels
> Subject: Re: AeroElectric-List: Dimmers > >
Is there a solid state dimmer available yet that only uses the power needed
to light the bulbs without spilling over excess as heat?
Message 22
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| Subject: | Re: Dimmers -- and LED trends |
--> AeroElectric-List message posted by: Canyon <steve.canyon@verizon.net>
Robert L. Nuckolls, III wrote:
>... and with the lighting current requirements going DOWN instead of
>up by using LEDs, the switchmode dimmers may never make it to the B&C
>catalog.
---
Hi Bob and All,
This is what I'm now considering -- LEDS White, RS supplied as
superbright, 1100 mcd, 3.64 VDC, 0.020 A. I have no comparison in my
memory to tell me whether this is the LED most are using for this
application but it sounds like it could be. As a prelude to use in an
RV, I'm thinking of fabricating a replacement for some small halogen
12VDC under cabinet counter lights in the kitchen. If this works as I
expect, then onto the RV application.
Any advice as to whether this is the best choice for white LEDS from
RadioShack or is there a better LED/source?
Thanks
Steve
Message 23
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| Subject: | Re: Bob, external power receptacle |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 05:57 PM 10/20/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: "J. Oberst"
><joberst@cox-internet.com>
>
>Bob, I put your ground power circuit (without the indicator) into my
>Glasair. One morning, I came into my hangar and found the airplane battery
>dead.
>
>The problem was that if you charge your battery, and then unplug the charger
>without pulling out the controlling circuit breaker, the charging contactor
>stays energized (and therefore drawing current) even with the master battery
>switch off. This is an easy mistake to make.
That is an operational disadvantage of the single-pin, Piper
style ground power connector . . . if a 3-pin, mil-spec device,
the ground power contactor can be automatically force off when
the plug is pulled.
Yes . . . there are a number of switches in most airplanes that
that will run the battery down if left ON. To drive down probability
of the scenario you describe (1) I called out a switch-breaker (the
only time I've ever found this device REALLY useful) so that it
can be perceived and treated like a switch. (2) I added a ground
power energized annunciator light (which would be illuminated
any time the ground power contactor is closed irrespective of
the power source).
When one walks away from the airplane, whether post-flight
or post-maintenance, the use of a checklist . . . or at least
a scan of the panel to make sure nothing is lit up is a good
thing to do.
Bob . . .
Message 24
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| Subject: | Re: Source for BNC adapters? |
--> AeroElectric-List message posted by: HCRV6@aol.com
In a message dated 10/21/03 8:05:52 AM Pacific Daylight Time,
bob.nuckolls@cox.net writes:
<< I'm not familiar with this part. Got a picture?
Bob . . . >>
I'm looking for a decent picture, lacking that I'll try to come up with a
sketch.
Do not archive
Harry Crosby
Pleasanton, California
RV-6, firewall forward
Message 25
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| Subject: | Re: Battery Contactor vibration problem |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:32 AM 10/21/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: Vince Ackerman <vack@mac.com>
>
>I guess I'll look into making a battery direct bus to run the Fadecs,
>ign packs and fuel pumps, although it would be pretty much negating the
>reason I put the contactor in there in the first place. Not much left
>to be switched by a contactor.
It's a backup disconnect for a stuck starter contactor. It's
a means for
> I wanted to be able to remove all power
>from the aircraft busses, for several reason one of which was to try to
>reduce electrolysis problems with the coolant and aluminum
>block/radiator.
don't understand how cold wiring helps avoid airframe corrosion . . .
> On the plus side, leaving it as is, even if I lost the
>contactor the alternator would still be providing power to the bus as
>long as the engine was running.
> If it isn't , then I don't need them
>anyway : ). How would I wire the battery bus / essential bus to be
>powered by the alternator/battery in normal mode, powered by the
>battery if the alternator died, and powered by the alternator alone if
>the contactor failed? Guess I'll spend some time looking at appendix
>Z.
For a single alternator, electrically dependent engine
flying machine, Figure Z-11 with a second battery is my
suggested architecture. Each pump/fadec combo runs from its
own battery bus. If this is a day/vfr only machine, then
you probably don't need the ebus . . . Given what I've
studied so far and based on the present state of our
conversation, here's how I think I'd wire MY helicopter.
http://www.aeroelectric.com/articles/Appendix_Z_Drawings/Z11H_Rotorway.pdf
Bob . . .
> Wonder if there's a way to make a warning light that tells you the
>contactor has failed (powered by the alternator)? I don't have a lot of
>space on this thing to add components or modify the electrical system.
>The electrical busses are contained in the overhead switch panel which
>is only 12 x 8 inches.
Hmmmm . . . the "buses" can be fuseblocks mounted anywhere. A failure
tolerant system shouldn't impact the present switch arrangements. I'm
REALLY skeptical of the fuse sizes called out on the Rotorway drawing.
It would be useful to have some real engineering data on current draw
for the various systems.
Bob . . .
Message 26
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:20 AM 10/21/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Bob Kuc" <bkuc1@tampabay.rr.com>
>
>Jim,
>I am doing the same thing on my velocity. However, I put my largish LEDs in
>the overhead console. I have three of them that light up the whole panel.
>While I am not flying yet, I have sat in the garage with all the lights out
>and it does light up the panel very nicely, but not that brightly. I am not
>planning on putting a dimmer on. If you look at Jim Weir's site, he had an
>article that used an op amp to oscillate to get a higher voltage through the
>LEDs.
??? Even the highest voltage LEDs are on the order of 4 volts. Can
you describe why some kind of "boost" was necessary?
Bob . . .
Message 27
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--> AeroElectric-List message posted by: John Schroeder <jschroeder@perigee.net>
Bob -
Can you confirm that it is ok to use this design of yours with LED's. For
example, with a red cluster and white cluster in an overhead cabin flood
light. Or with a string of blue-green LED's under the glare shield as
panel floods.
Thanks,
John
>> I have the solid state unit from B&C. The one that comes with the goose
>> neck
>> light. It's small and dims 4 or 5 outputs. Works well with LEDS, not
>> expensive, and much easier than making one.
>> John Slade
>
> That's the 0.5A version. Exactly the same electronics as
> all other sizes, just no heatsink. This is an approximate
> equal to Van's sink-less product.
>
> Bob . . .
Message 28
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| Subject: | Re: Dimmers -- and LED trends |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
Steve
>This is what I'm now considering -- LEDS White, RS supplied as
>superbright, 1100 mcd, 3.64 VDC, 0.020 A.
>Any advice as to whether this is the best choice for white LEDS from
>RadioShack or is there a better LED/source?
Check eBay for leds. These guys sell white leds (and other colors) for
cheap!
Example of price---100 Ultra White LED 5mm 7000mcd Free Shipment $28.
That's $0.28 each! 1000 pc for $190. $0.19 each!
cwithk--- Chi Wing LED product shop
deidynamic2000--- Dynamic Electronics and IT Products
hkcitytrader--- HKCityShop
The higher priced 5 mm white leds are now around 12000 mcd!
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
I'm not going to buy my kids an encyclopedia. Let them walk to school like I
did.
--Yogi Berra
Message 29
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| Subject: | Re: Track width on PCB |
--> AeroElectric-List message posted by: "Gilles.Thesee" <Gilles.Thesee@ac-grenoble.fr>
----- Message d'origine -----
De : "David E. Nelson" <david.nelson@pobox.com>
: <aeroelectric-list@matronics.com>
Envoy : mercredi 15 octobre 2003 17:46
Objet : Re: AeroElectric-List: Track width on PCB
> --> AeroElectric-List message posted by: "David E. Nelson"
<david.nelson@pobox.com>
>
>
> Hi Gilles,
>
> I did a google seach (pcb track width current amps) and found a PCB track
width
> calculator:
>
> http://www.geocities.com/CapeCanaveral/Lab/9643/TraceWidth.htm
>
> Regards,
> /\/elson
Thanks to all who responded,
Regards
Gilles
Message 30
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| Subject: | Magnetos and preflight testing . . . |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
>Comments/Questions: Hi Bob,
> A magneto clarification Question-----when you select left mag on a
> mag check,Are you grounding out the left mag and getting a mag drop
> reading from the right mag,and vice versa or am I totatally confused and
> miseducated about mag operating concept?Please educate me on this topic
> and/or direct me to where I can get a layman's explanation on how this
> all works.
Let's talk about "mag drop" as a test data point.
The speed at which a flame front progresses across
the top of a piston is a function of mixture and
pressure but mostly pressure. The higher the
pressure, the faster the burn. Given the relatively
large diameter pistons in aircraft engines -AND-
location of plugs on opposite sides, there is an
effective change in ignition timing depending on
whether one or two ignition systems are in operation.
When you light TWO fires at opposite sides of the
piston, two flame fronts meet sorta in the middle
with total ignition happening sooner than if you
light the fire at one side only where a single flame
front has to go all the way across the top of piston.
Depending on mixture and the octane rating of the
fuel, you can experience a huge increase in flame
front velocity. Once the fire is lighted, pressures
climb very quickly due to heat released as part of
the combustion process. If octane rating is too low,
the pressure front (travels faster than flame front)
drives pressures in un-burned mixture so high that it
ignites all at once - the explosion is called detonation.
Diesel engines are designed to WORK in this mode of
ignition, 4-cycle gasoline engines break in this mode
of operation . . .
Magnetos, as fixed timing devices, must be timed
so that under worst case conditions (full throttle,
lowest quality fuel, sea-level operation, highest
temperatures, etc, etc) the timing is not so advanced
that detonation will happen. This setting has to
consider the effective advance in timing that
occurs when two magnetos light fires on both sides
of the piston. Needless to say, while the engine
will run at altitude on one magneto, the low manifold
pressures combined with retarded effective timing
will produce a significant decrease in performance.
This is where the electronic ignition with variable,
scheduled timing can stand head-n-shoulders above
the lowly farm tractor ignition system.
During a so-called magneto test during preflight,
we're shown how to explore TWO aspects of magneto
operation. At some RPM higher than idle but with still
relatively low manifold pressures we shut off one
mag at a time. Two things are observed during single
magneto operation: (1) We see that the mag still running
is working and that all plugs are firing . . . (2) we
see a slight drop in RPM due to effective retardation
of ignition timing during single-ignition operation.
Then, we repeat the observation on the other
mag. Noting magnitude of drop is a rough check
of total effective timing . . . noting the same RPM
drop for each mag says they're well synchronized
to each other.
Then comes an potential for confusion when trying
to write a squawk describing a magneto problem.
When you turn a key switch to "L" (engine runs on
left mag only) and the engine stumbles . . . you
can confidently write "left magneto tests bad on
run-up". If you have toggle switches, testing the
LEFT mag requires you turn OFF the RIGHT mag. It's
a common mistake for a pilot to belive that turning
the switch marked "R MAG" OFF is a test of the right
mag and he/she squawks the wrong mag.
If you have any combination of electronic ignition,
it is possible that the electronic ignition will be
advanced to optimum timing for the engine speed and
manifold pressures during run-up. The important fact
to be gathered by running the engine from one
ignition source at a time is to prove that both
sources are working. RPM notations are dependent
design and programming of the electronic ignition
and may or may not have any significance during
preflight testing.
Bob . . .
Message 31
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--> AeroElectric-List message posted by: "Bob Kuc" <bkuc1@tampabay.rr.com>
Jim wrote an article on how to get more light from an LED. Basically by
flashing the LED at 120 Hz with 1/4 duty you can use higher voltage through
the LED that what it was rated for, the eye sees the brighter light as
steady.
His article can explain it much better that I can. Here is the link to
Jim's article and schematic on how to build it. It does contain a pot to
adjust the brightness http://www.rst-engr.com/kitplanes/KP0010/KP0010.htm
I used this schematic to drive three jumbo defused LEDs that allows me to
light my panel from my overhead console. While I was testing this in my
garage on late evening, my wife decided to go to bed, looked in the garage
and saw that it was dark, locked it up with me still in the garage.
Needless to say, scared the begeezus out of here when I started to bang on
the garage door :-)
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
Subject: Re: AeroElectric-List: Dimmers
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
>
> At 11:20 AM 10/21/2003 -0400, you wrote:
> >--> AeroElectric-List message posted by: "Bob Kuc"
<bkuc1@tampabay.rr.com>
> >
> >Jim,
> >I am doing the same thing on my velocity. However, I put my largish LEDs
in
> >the overhead console. I have three of them that light up the whole
panel.
> >While I am not flying yet, I have sat in the garage with all the lights
out
> >and it does light up the panel very nicely, but not that brightly. I am
not
> >planning on putting a dimmer on. If you look at Jim Weir's site, he had
an
> >article that used an op amp to oscillate to get a higher voltage through
the
> >LEDs.
>
> ??? Even the highest voltage LEDs are on the order of 4 volts. Can
> you describe why some kind of "boost" was necessary?
>
> Bob . . .
>
---
Message 32
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--> AeroElectric-List message posted by: plaurence@the-beach.net
On 21 Oct 2003 at 8:35, Jim Sower wrote:
>For those who need to mix and match LED with Incondesent bulbs, check out this
site.
http://www.a-and-t-labs.com/K11_Dimmer/index.htm
peter
Message 33
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| Subject: | Re: Dimmers -- and LED trends |
--> AeroElectric-List message posted by: Canyon <steve.canyon@verizon.net>
Eric M. Jones wrote:
>Check eBay for leds. These guys sell white leds (and other colors) for
>cheap!
>Example of price---100 Ultra White LED 5mm 7000mcd Free Shipment $28.
> That's $0.28 each! 1000 pc for $190. $0.19 each!
Thanks, Eric -- I don't know squat about candlepower, at least from
practical experience. Though the 1100mcd sounded low though.
>cwithk--- Chi Wing LED product shop
> deidynamic2000--- Dynamic Electronics and IT Products
> hkcitytrader--- HKCityShop
>
>The higher priced 5 mm white leds are now around 12000 mcd!
I'll check these out -- thanks again!
Steve
Message 34
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| Subject: | Re: Dimmers -- and LED trends |
--> AeroElectric-List message posted by: John Schroeder <jschroeder@perigee.net>
Steve -
I bought a bunch of white LEDs off eBay and have both of your problems:
dimming LED's in an aircraft and replacing some miserable halogens under
our kitchen cabinets. Keep us posted on your progress.
do not archive
John Schroeder
On Tue, 21 Oct 2003 12:35:30 -0500, Canyon <steve.canyon@verizon.net>
wrote:
> This is what I'm now considering -- LEDS White, RS supplied as
> superbright, 1100 mcd, 3.64 VDC, 0.020 A. I have no comparison in my
> memory to tell me whether this is the LED most are using for this
> application but it sounds like it could be. As a prelude to use in an
> RV, I'm thinking of fabricating a replacement for some small halogen
> 12VDC under cabinet counter lights in the kitchen. If this works as I
> expect, then onto the RV application.
Message 35
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| Subject: | Re: LED Position Lights |
--> AeroElectric-List message posted by: "Dawson, Bill" <Bill.Dawson@pepperdine.edu>
-----Original Message-----
From: Shaun Simpkins [mailto:shauns@hevanet.com]
Subject: AeroElectric-List: Re: LED Position Lights
--> AeroElectric-List message posted by: "Shaun Simpkins"
<shauns@hevanet.com>
>You're close. The emitters appear to be the 1W Luxeon Star-O in a custom
heat sink/circuit board.
>These units run at 350mA and 4.0V worst case ( about 3.3V for red ), so 7
of them in series just
> fit in a 28V system. No 28-to-56V step-up unit required. The Star-O,
because of its optics,
>can put out a really bright beam - over 180 candela.
Whelen confirms that the 70875 position lights mentioned in this thread over
the last few weeks are
using the Luxeon Star-O emitters. The housing contains only a heat sink,
and the emitters are derated
20% for maximum reliability. The list price of these items is about $460 -
expect the street price to be
around $250. Whelen will be changing over its entire aviation filament-based
illuminators
to LED-based over the next two years or so. The economies of scale of its
emergency vehicle and
industrial divisions are allowing its aviation division to modernize its
products. A/C mfgs are chomping
at the bit, but more for the install-and-forget reliability rather than the
power savings.
Shaun
Message 36
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--> AeroElectric-List message posted by: John R <jrourke@allied-computer.com>
I looked around on his website, and didn't see any article boosting the
"voltage" to an LED... and as you say, it really wouldn't do much
(except posssibly overheat the current-limiting resistor I suppose...)
However, if he was indeed making an *oscillator*, there is a trick to
make the LED *appear* to be brighter, by driving it at some fractional
duty cycle at a multiple of the current... so if an LED is rated to 20mA
at 100% duty cycle, you can drive it at 200mA at 10%... the human eye
will perceive it to be brighter, even though the total power is the same.
Come to think of it, that could be a neat way to make a dimmer for LEDs...
-John R.
Robert L. Nuckolls, III wrote:
>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
>
>At 11:20 AM 10/21/2003 -0400, you wrote:
>
>
>>--> AeroElectric-List message posted by: "Bob Kuc" <bkuc1@tampabay.rr.com>
>>
>>Jim,
>>I am doing the same thing on my velocity. However, I put my largish LEDs in
>>the overhead console. I have three of them that light up the whole panel.
>>While I am not flying yet, I have sat in the garage with all the lights out
>>and it does light up the panel very nicely, but not that brightly. I am not
>>planning on putting a dimmer on. If you look at Jim Weir's site, he had an
>>article that used an op amp to oscillate to get a higher voltage through the
>>LEDs.
>>
>>
>
> ??? Even the highest voltage LEDs are on the order of 4 volts. Can
> you describe why some kind of "boost" was necessary?
>
> Bob . . .
>
>
>
>
Message 37
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rv-list@matronics.com
| Subject: | B&C regulator for sale |
10/21/2003 08:10:23 PM,
Serialize complete at 10/21/2003 08:10:23 PM
--> AeroElectric-List message posted by: Bob Bittner <rbittner@us.ibm.com>
Hi all.
I ordered a B&C LR-3 14V alternator controller / OV protection, but I'm
going to use an internally regulated alternator instead. It's still
new-in-box, unopened condition. I could send it back to Aircraft Spruce,
but I thought I might just as well see if anyone here wants it. I can
ship it to you without sales tax or shipping charge (pay via PayPal) and
probably a bit sooner... otherwise, I'll just send it back to AS.
Bob B
Message 38
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| Subject: | Re: Dimmers -- and LED trends |
--> AeroElectric-List message posted by: Canyon <steve.canyon@verizon.net>
John Schroeder wrote:
>I bought a bunch of white LEDs off eBay and have both of your problems:
>dimming LED's in an aircraft and replacing some miserable halogens under
>our kitchen cabinets. Keep us posted on your progress.
---
Don't know how soon I can do this but I'm going to start gathering the
parts. Will post anything successful when I finish.
Aren't those under cabinet pin-socket bulbs fun!? Like to have the
engineer who designed that abomination in a position to force him to
study reliability physics in a sealed room lighted only with his
invention. I'd bet he would come up with something much better rather
quickly or be left in the dark! :-)
Steve
do not archive
Message 39
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--> AeroElectric-List message posted by: Jim Sower <canarder@frontiernet.net>
<... much more efficient - linear regulators dissipate any excess power as heat,
so you use the same amount of power ...>
<... All things considered, I'd stick with a linear design like B&C's ...>
I thought a linear regulator varied the voltage to the lights and wouldn't work
on a LED - that they are either on or off and you need to flash them to make
them look dim. Could I use a linear regulator? And how is it different from
a pot?
Wondering if I'm asking the right questions now ... Jim S.
"Robinson, Chad" wrote:
> --> AeroElectric-List message posted by: "Robinson, Chad" <crobinson@rfgonline.com>
>
> > Is there a solid state dimmer available yet that only uses
> > the power needed to light the bulbs without spilling over
> > excess as heat?
>
Message 40
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--> AeroElectric-List message posted by: "Robinson, Chad" <crobinson@rfgonline.com>
> I looked around on his website, and didn't see any article boosting the
> "voltage" to an LED... and as you say, it really wouldn't do much
> (except posssibly overheat the current-limiting resistor I suppose...)
John, you made a good point about pulse width modulation (PWM) to make LEDs seem
brighter at the same power levels, but I'd like to respond to this other point.
Yes and no. A higher voltage WOULD make the LED brighter, because it's the
difference between the supply voltage and the LED's forward voltage drop that
determines the drop across the resistor, and thus the current flow through the
whole shebang.
Normally, you look at the data sheet for the LED and see that it has, say, a 1.7V
drop and a max current rating of 50mA. So maybe you knock off 5mA to keep them
living as long as possible and end up with 45mA. Now supposing you have an
"ideal" main bus voltage of 13.8V. That means you're dropping 12.1V across the
resistor. E = I * R, so 12.1V = 0.045 * R. Solving for R, you get a resistance
of about 269 ohms. Interestingly enough, you can find 270 ohm resistors fairly
readily (red purple brown), so that makes a good size.
[ I didn't mean for that explanation to patronize anybody, but it's been a while
since I last saw it mentioned, and it's sort of a regular question so I figured
I'd make a round of it for the benefit of the lurkers. Bob, maybe you should
make a FAQ? =) ]
I think Bob's point was that even the biggest LEDs (and these are monsters, please
note) only have a 4V drop, so there's still plenty of room to calculate decent
limiting resistors for this (200 ohms gives you roughly 50mA here, for instance).
So it's a puzzle as to why somebody would need to boost the voltage.
Normally, all that matters is that you're a certain amount above the forward voltage
drop of the diode.
May I take a guess? Betcha these aren't for LEDs. Switch mode regulators are quite
similar to the inverters used to power EL light strips, and I've seen a few
mentions of those mentioned recently. They require AC to excite them, usually
at anywhere from 100-400 volts, so it's definitely a "step up" application.
Also, I looked at RST's site, at Jim Weir's articles, and it looks like his "mother
of all lamp dimmers" was designed for lamps, not LEDs (although it could
certainly handle both, to an extent).
There are some advantages to both designs, but gosh, look at all the parts. =)
With LEDs drawing as little power as they do, it's probably overkill. (That's
a hypocritical statement for anybody who's seen my glass cockpit design, but what
the hey. <grin>)
Regards,
Chad
Message 41
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--> AeroElectric-List message posted by: Jim Sower <canarder@frontiernet.net>
Bob,
It looks at this point like I'll be getting the B&C unit everyone's suggesting.
It's also becoming apparent that I was maybe posing the question based on false
premises around how stuff works.
Bob Kuc wrote:
> --> AeroElectric-List message posted by: "Bob Kuc" <bkuc1@tampabay.rr.com>
>
> Jim,
> I am doing the same thing on my velocity. However, I put my largish LEDs in
> the overhead console. I have three of them that light up the whole panel.
> While I am not flying yet, I have sat in the garage with all the lights out
> and it does light up the panel very nicely, but not that brightly. I am not
> planning on putting a dimmer on. If you look at Jim Weir's site, he had an
> article that used an op amp to oscillate to get a higher voltage through the
> LEDs. I believe that the schematic did contain a pot for dimming it if
> needed. You should be able to use that. The board should not be big at
> all.
Message 42
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--> AeroElectric-List message posted by: John R <jrourke@allied-computer.com>
Well, I was trying to keep my reply uncharacteristically simple and
direct... yes, a higher supply voltage will increase the Vdrop across
the resistor, which increases the current in both the resistor and the
LED, which increases the heat dissipated by the resistor, and light
output of the LED... to a point. (LEDs have ratings for a reason; too
much and they will indeed glow more brightly - for a while. Maybe even
REAL bright. and then, real DARK! :-)
But in any event, although I'm not certain what Bob's "???" specifically
referred to (you're probably right), I was just thinking that if you
wanted to boost an LED's output, you generally don't do it by throwing
more voltage at it - and if you did, using an oscillator to do it is the
long way 'round to end up at the same problem - the higher voltage
across the resistor generates a lot of wasted heat, which is what we're
trying to avoid.
I vote for the PWM as the most likely explanation for a design involving
an oscillator.Yes, it's somewhat more complex (although a 556, a few
caps and resistors will do the trick nicely I should think), but does
not create much excess heat, and can function both as a dimmer and a
"booster".
I'd like to find the article though.
-John
Robinson, Chad wrote:
>--> AeroElectric-List message posted by: "Robinson, Chad" <crobinson@rfgonline.com>
>
>
>
>>I looked around on his website, and didn't see any article boosting the
>>"voltage" to an LED... and as you say, it really wouldn't do much
>>(except posssibly overheat the current-limiting resistor I suppose...)
>>
>>
>
>John, you made a good point about pulse width modulation (PWM) to make LEDs seem
brighter at the same power levels, but I'd like to respond to this other point.
Yes and no. A higher voltage WOULD make the LED brighter, because it's the
difference between the supply voltage and the LED's forward voltage drop that
determines the drop across the resistor, and thus the current flow through the
whole shebang.
>
>Normally, you look at the data sheet for the LED and see that it has, say, a 1.7V
drop and a max current rating of 50mA. So maybe you knock off 5mA to keep
them living as long as possible and end up with 45mA. Now supposing you have an
"ideal" main bus voltage of 13.8V. That means you're dropping 12.1V across the
resistor. E = I * R, so 12.1V = 0.045 * R. Solving for R, you get a resistance
of about 269 ohms. Interestingly enough, you can find 270 ohm resistors fairly
readily (red purple brown), so that makes a good size.
>
>[ I didn't mean for that explanation to patronize anybody, but it's been a while
since I last saw it mentioned, and it's sort of a regular question so I figured
I'd make a round of it for the benefit of the lurkers. Bob, maybe you should
make a FAQ? =) ]
>
>I think Bob's point was that even the biggest LEDs (and these are monsters, please
note) only have a 4V drop, so there's still plenty of room to calculate decent
limiting resistors for this (200 ohms gives you roughly 50mA here, for instance).
So it's a puzzle as to why somebody would need to boost the voltage.
Normally, all that matters is that you're a certain amount above the forward
voltage drop of the diode.
>
>May I take a guess? Betcha these aren't for LEDs. Switch mode regulators are quite
similar to the inverters used to power EL light strips, and I've seen a few
mentions of those mentioned recently. They require AC to excite them, usually
at anywhere from 100-400 volts, so it's definitely a "step up" application.
Also, I looked at RST's site, at Jim Weir's articles, and it looks like his "mother
of all lamp dimmers" was designed for lamps, not LEDs (although it could
certainly handle both, to an extent).
>
>There are some advantages to both designs, but gosh, look at all the parts. =)
With LEDs drawing as little power as they do, it's probably overkill. (That's
a hypocritical statement for anybody who's seen my glass cockpit design, but
what the hey. <grin>)
>
>Regards,
>Chad
>
>
>
>
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