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rv6a(at)rogers.com
Guest

Posted: Mon Oct 27, 2014 3:23 pm Post subject: LED

Hi



I am trying to use a 12 volt LED for an "Alt Warn" light.  The alternator manufacturer provides a wiring diagram for the warning light and specifies using a 100ma light.  The LED specs that I want to use are 12v and 20ma.  When I try and use the LED as is, there is intermittent low intensity flickering of the warning light while the engine is running.  The alternator output is a constant 14.5 volts.  The problem is eliminated by using a 100ma incandescent lamp as per the manufacturer's recommendation.  I would suspect that there is a small amount of current in the warning circuit that is enough to cause intermittent operation of the LED, albeit very dimly.  The LED does go to full intensity when operating in a warning mode.   Can a resister be added to the circuit to make the LED comparable with the Alt manufacturer's spec of using 100ma lamp.  If so, what size resister and is installed in parallel?  It would be nice if I can use the LED, as it matches the other lights in my annunciation panel.



Thanks,



John C

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Oct 27, 2014 3:55 pm Post subject: LED

At 18:22 2014-10-27, you wrote:




Hi



I am trying to use a 12 volt LED for an "Alt Warn" light.  The 

alternator manufacturer provides a wiring diagram for the warning 

light and specifies using a 100ma light.  The LED specs that I want 

to use are 12v and 20ma.  When I try and use the LED as is, there is 

intermittent low intensity flickering of the warning light while the 

engine is running.  The alternator output is a constant 14.5 

volts.  The problem is eliminated by using a 100ma incandescent lamp 

as per the manufacturer's recommendation.  I would suspect that there 

is a small amount of current in the warning circuit that is enough to 

cause intermittent operation of the LED, albeit very dimly.  The LED 

does go to full intensity when operating in a warning mode.   Can a 

resister be added to the circuit to make the LED comparable with the 

Alt manufacturer's spec of using 100ma lamp.  If so, what size 

resister and is installed in parallel?  It would be nice if I can use 

the LED, as it matches the other lights in my annunciation panel.



   Where does this alternator warn signal come from? Out of

   the alternator? Those built-in warning circuits are not

   all inclusive for alternator failure. Does your system

   include a LOW VOLTS warning light? LOW VOLTS WARN is the PRIMARY

   and all-inclusive annunciation for alternator health.



   Bob . . .

rv6a(at)rogers.com
Guest

Posted: Mon Oct 27, 2014 4:23 pm Post subject: LED

The signal comes the alternator.  The light indicates an "Alternator  Out" condition.



 	  Quote: 	
		   On Oct 27, 2014, at 7:53 PM, "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com> wrote:

 

 

 

 At 18:22 2014-10-27, you wrote:

 

 

 Hi

 

 I am trying to use a 12 volt LED for an "Alt Warn" light.  The alternator manufacturer provides a wiring diagram for the warning light and specifies using a 100ma light.  The LED specs that I want to use are 12v and 20ma.  When I try and use the LED as is, there is intermittent low intensity flickering of the warning light while the engine is running.  The alternator output is a constant 14.5 volts.  The problem is eliminated by using a 100ma incandescent lamp as per the manufacturer's recommendation.  I would suspect that there is a small amount of current in the warning circuit that is enough to cause intermittent operation of the LED, albeit very dimly.  The LED does go to full intensity when operating in a warning mode.   Can a resister be added to the circuit to make the LED comparable with the Alt manufacturer's spec of using 100ma lamp.  If so, what size resister and is installed in parallel?  It would be nice if I can use the LED, as it matches the other lights in my annunciation panel.

 

  Where does this alternator warn signal come from? Out of

  the alternator? Those built-in warning circuits are not

  all inclusive for alternator failure. Does your system

  include a LOW VOLTS warning light? LOW VOLTS WARN is the PRIMARY

  and all-inclusive annunciation for alternator health.

 

 

 

  Bob . . . 

 

====================================
	


====================================

====================================

====================================

 	  Quote: 	
		   

 

 


	


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nuckolls.bob(at)aeroelect
Guest

Posted: Mon Oct 27, 2014 4:48 pm Post subject: LED

At 19:22 2014-10-27, you wrote:

 	  Quote: 	
		  The signal comes the alternator.  The light indicates an 

"Alternator  Out" condition.


	


   If you leave the lamp disconnected, does the

   alternator still operate? Some early internal

   regulators were designed to shut down if the

   warning lamp burned out. Lots of owners spliced

   a reistor around the lamp to make sure it stayed

   on line with a dead-bulb.



   If it will run without a lamp, then ignore the

   wire. If a lamp has to be in place for the

   alternator to run, then wire the terminal

   to the b-terminal with a 150-ohm, 2w resistor.

   I can send you one if you have trouble finding

   one.



   On the flip side of decision, plan on a low

   volts warning system of some type. I can show

   you how to build one or order one from a

   variety of sources.

   Bob . . .

rv6a(at)rogers.com
Guest

Posted: Mon Oct 27, 2014 6:01 pm Post subject: LED

Bob, I appreciate your help with this.  The alternator runs without the lamp (the manufacturer advises that it is optional).  The plane has already been wired for the "Alternator Out" lamp and panel labelled.  As such, I am thinking that I would like to keep it if I can get it to work with the LED.  I agree with you on merits of a low voltage warning and have configured my EIS to alert to such a condition.





 	  Quote: 	
		   On Oct 27, 2014, at 8:47 PM, "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com> wrote:

 

 

 

 At 19:22 2014-10-27, you wrote:

> The signal comes the alternator.  The light indicates an "Alternator  Out" condition.

 

  If you leave the lamp disconnected, does the

  alternator still operate? Some early internal

  regulators were designed to shut down if the

  warning lamp burned out. Lots of owners spliced

  a reistor around the lamp to make sure it stayed

  on line with a dead-bulb.

 

  If it will run without a lamp, then ignore the

  wire. If a lamp has to be in place for the

  alternator to run, then wire the terminal

  to the b-terminal with a 150-ohm, 2w resistor.

  I can send you one if you have trouble finding

  one.

 

  On the flip side of decision, plan on a low

  volts warning system of some type. I can show

  you how to build one or order one from a

  variety of sources.

 

 

  Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Oct 27, 2014 6:36 pm Post subject: LED

At 20:59 2014-10-27, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: John <rv6a(at)rogers.com>



 Bob, I appreciate your help with this.  The alternator runs without the lamp (the manufacturer advises that it is optional).  The plane has already been wired for the "Alternator Out" lamp and panel labelled.  As such, I am thinking that I would like to keep it if I can get it to work with the LED.  I agree with you on merits of a low voltage warning and have configured my EIS to alert to such a condition. 	


    Low volts being labeled ALT OUT is not inconsistent.



    Use a 150 ohm resistor to 'dummy load' the output

    signal. Put 470 in series with LED in parallel with

    150 ohm. Adjust 470 ohm resistor upward if too bright.



 [img]cid:7.1.0.9.0.20141027212801.01f973b8(at)aeroelectric.com.0[/img] 



 

 

   Bob . . .

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crabandy(at)yahoo.com
Guest

Posted: Mon Oct 27, 2014 7:09 pm Post subject: LED

Not to hijack this thread, but.....

I have a LED lighting strip under my glare shield for flood lighting that is controlled by a PWM dimmer. It is too bright for night ops and was wondering if I may be able to use a resistor like in this example to dim it further. 

Thanks,

Andy



Sent from my iPhone



On Oct 27, 2014, at 9:35 PM, "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:

[quote]  At 20:59 2014-10-27, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: John <rv6a(at)rogers.com (rv6a(at)rogers.com)>



 Bob, I appreciate your help with this.  The alternator runs without the lamp (the manufacturer advises that it is optional).  The plane has already been wired for the "Alternator Out" lamp and panel labelled.  As such, I am thinking that I would like to keep it if I can get it to work with the LED.  I agree with you on merits of a low voltage warning and have configured my EIS to alert to such a condition. 	


    Low volts being labeled ALT OUT is not inconsistent.



    Use a 150 ohm resistor to 'dummy load' the output

    signal. Put 470 in series with LED in parallel with

    150 ohm. Adjust 470 ohm resistor upward if too bright.



 <24974424.jpg> 



 

 

   Bob . . .  

[b]

rv6a(at)rogers.com
Guest

Posted: Mon Oct 27, 2014 7:25 pm Post subject: LED

Thanks Bob.  

On Oct 27, 2014, at 10:35 PM, "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:

[quote]  At 20:59 2014-10-27, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: John <rv6a(at)rogers.com (rv6a(at)rogers.com)>



 Bob, I appreciate your help with this.  The alternator runs without the lamp (the manufacturer advises that it is optional).  The plane has already been wired for the "Alternator Out" lamp and panel labelled.  As such, I am thinking that I would like to keep it if I can get it to work with the LED.  I agree with you on merits of a low voltage warning and have configured my EIS to alert to such a condition. 	


    Low volts being labeled ALT OUT is not inconsistent.



    Use a 150 ohm resistor to 'dummy load' the output

    signal. Put 470 in series with LED in parallel with

    150 ohm. Adjust 470 ohm resistor upward if too bright.



 <24974424.jpg> 



 

 

   Bob . . .  

[b]

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Oct 28, 2014 3:45 am Post subject: LED

At 22:08 2014-10-27, you wrote:

Not to hijack this thread, but.....



I have a LED lighting strip under my glare shield for flood lighting 

that is controlled by a PWM dimmer. It is too bright for night ops 

and was wondering if I may be able to use a resistor like in this 

example to dim it further.



    The dimmer you have won't take it down enough?

    Most dimmer designs I've seen operate over the

    full range of max bright to off. Yes, you can

    certainly add a resistor to reduce the intensity

    for ALL settings of the dimmer but I'd investigate

    why the present dimmer's behavior is inadequate to

    the task.

   Bob . . .

Eric M. Jones

Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts

Posted: Tue Oct 28, 2014 9:24 am Post subject: Re: LED

This should work: Attached PDF

Alternator LED.pdf

Description:

Alternator LED Warning Light

Download

Filename:

Alternator LED.pdf

Filesize:

129.17 KB

Downloaded:

352 Time(s)

_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net

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