![Matronics Email Lists Forum Index](templates/Matronics/images/logo_phpBB.gif) |
Matronics Email Lists Web Forum Interface to the Matronics Email Lists
|
View previous topic :: View next topic |
Author |
Message |
d_emond(at)mweb.co.za Guest
|
Posted: Sun Dec 23, 2007 1:50 am Post subject: LED warning lights |
|
|
Hi Bob
I have gone with Z-12 architecture and I am using B&C 60amp alternator and
their standby SB1B-14.
My Question: What is the recommended way to substitute normal 12 volt
warning lights for LED's??
Merry Christmas
Dave Emond
| - The Matronics AeroElectric-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
Back to top |
|
![](templates/Matronics/images/spacer.gif) |
h&jeuropa
Joined: 07 Nov 2006 Posts: 647
|
Posted: Mon Dec 24, 2007 5:38 am Post subject: Re: LED warning lights |
|
|
Dave,
There is a document on the AeroElectric website that explains how to use LEDs. Basically you need to have a current limiting resistor in series with the LED.
You'll find that "electronic switches" often have enough leakage current so that a LED will remain illuminated somewhat even though it should be off. The solution for that is a resistor across the LED. You should check with the manufacturer of any device you are using to get their recommendation for how to handle this situation. For instance if you have a B&C LR3C-14, they want a 510 ohm resistor between terminal 3 & 5. GRT EIS wants 10K ohm across the warning light.
I have nothing but LEDs in all my warning and status lights and they work great! and no filament to burn out and fail!
Jim Butcher
Europa XS
N241BW
| - The Matronics AeroElectric-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
Back to top |
|
![](templates/Matronics/images/spacer.gif) |
longg(at)pjm.com Guest
|
Posted: Mon Dec 24, 2007 6:03 am Post subject: LED warning lights |
|
|
Dave,
What makes you think you would treat LED's differently? Do they have a
defined voltage and a wattage? We'll then you treat them like any other
light. Yes, they generally take 1/3 as much power, but the ideology is
the same. Now, if you have the plutonium jobs, you need to mount them at
least 3 feet from major body parts.
--
| - The Matronics AeroElectric-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
Back to top |
|
![](templates/Matronics/images/spacer.gif) |
nuckolls.bob(at)cox.net Guest
|
Posted: Mon Dec 24, 2007 9:51 am Post subject: LED warning lights |
|
|
At 09:02 AM 12/24/2007 -0500, you wrote:
Quote: |
Dave,
What makes you think you would treat LED's differently? Do they have a
defined voltage and a wattage? We'll then you treat them like any other
light. Yes, they generally take 1/3 as much power, but the ideology is
the same. Now, if you have the plutonium jobs, you need to mount them at
least 3 feet from major body parts.
|
Not all that is "LED" is a drop in replacement for
incandescent lamps. An LED's operating voltage is
on the order of 2 volts. Further, it's intensity
is directly controlled by how much CURRENT that's
forced through the device. Here's a generic article
on the innate perversity of the little buggers . . .
http://www.aeroelectric.com/articles/leds3.pdf
Now, there ARE manufacturers of indicating light
FIXTURES that INCLUDE some form of current setting
resistor internal to the fixture. Examples include
devices like this:
http://tinyurl.com/2c3cxw
where one should note the callout, "Orange 12V LED
with holder". This description is a bit misleading
because there's no such thing as a "12V LED". There
are only ASSEMBLIES of an LED and a RESISTOR sized
for optimum operation at some voltage . . . in this
case, 12V.
There are many more LEDs in holders that do not
contain built in resistors like this:
http://www.aeroelectric.com/Pictures/Lighting/Mini-LED_Fixture.jpg
. . . which may be used in instllations like this:
http://www.aeroelectric.com/Pictures/Lighting/Annunciator_1.jpg
. . . where the resistors necessary to set up proper
operating current for the LEDs are external to the
lamp fixture but part of the overall system design.
Getting back to the B&C alternator controller
products, the output stage of the warning light
system was designed to TURN A WARNING LIGHT ON
in the event power was totally removed from the
controller. To accomplish this bit of electron
herding magic, the following architecture was
crafted:
http://www.aeroelectric.com/Pictures/Schematics/LV_Led.jpg
Note the resistor from transistor collector to
base INTERNAL to the LR-3. This causes a substantial
amount of what would otherwise be called leakage
current to flow in the transistor's collector lead
when the LR-3 is powered down.
When substituting an LED for the normal incandescent
lamp, the "leakage" current that does not produce
visible light output from an incandescent lamp will
produce substantial light output from an LED. Further,
direct substitution of an LED for the incandescent lamp
is not possible without limiting the current to the
LED as cited above. In this case, I've illustrated the
use of two, 220 ohm resistors wired to (1) limit
current in the ON state and (2) wash out the effects
of 'leakage current' in the OFF state.
There's nothing particularly magic about the selection
of 220 ohms . . . I picked it because it was adequate
to the task and readily available from Radio Shack in
a handy pak-of-5 for a dollar. See:
http://tinyurl.com/2dl6zy
Bottom line is that LED lighting products are NOT
a no-brainer, drop-in replacement for every incandescent
application. One must have a knowledge of the
design goals for the driving circuitry (such as what
that ol' fart in Wichita put in the B&C products 20
years ago!).
Bob . . .
| - The Matronics AeroElectric-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
Back to top |
|
![](templates/Matronics/images/spacer.gif) |
d_emond(at)mweb.co.za Guest
|
Posted: Mon Dec 24, 2007 12:23 pm Post subject: LED warning lights |
|
|
Bob
Thanks for answering.
Dave
Do Not Archive
---
| - The Matronics AeroElectric-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
Back to top |
|
![](templates/Matronics/images/spacer.gif) |
|
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum You cannot attach files in this forum You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|