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Push-to-Test Lamp

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hammer408(at)comcast.net
Guest

Posted: Wed Aug 27, 2008 3:56 pm Post subject: Push-to-Test Lamp

Bob:



I've purchased 2 Push-to-Test Lamps: MS25041 (amber) for my Low Voltage

Warning Lamp and another one (blue) for Low Oil Pressure.  The lamps have3

tabs, numbered 1-2-3 and I'm trying to determine how to wire this lamp:

which is ground, hot and common....



Any help or suggestions appreciated.



Henry

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currydon(at)bellsouth.net
Guest

Posted: Wed Aug 27, 2008 4:55 pm Post subject: Push-to-Test Lamp

I'm not Bob, but if I may, I'd like to provide at least a cursory answer.  I

just installed a pair of these lights (made by Dialight) in my aircraft and

here's how we did it (the attached document is from Dialight and should bear

this out).  There are two hot terminals and one ground terminal.  One of the

hot terminals is for a switched input, so when the condition you are trying

to alert yourself to (e.g., low oil pressure) occurs, the switch is closed

on that wire, the circuit is completed, and the light lights.  The other hot

terminal is unswitched and is for the push-to-test feature; it allows the

light to light when the lens is pressed even when the condition doesn't

exist.  I believe it is the center terminal that is the ground.  Hope this

helps.  Don



[quote] --

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nuckolls.bob(at)cox.net
Guest

Posted: Wed Aug 27, 2008 7:02 pm Post subject: Push-to-Test Lamp

At 07:58 PM 8/27/2008 -0700, you wrote:

 	  Quote: 	
		  

<hammer408(at)comcast.net>



Bob:



I've purchased 2 Push-to-Test Lamps: MS25041 (amber) for my Low Voltage

Warning Lamp and another one (blue) for Low Oil Pressure.  The lamps have3

tabs, numbered 1-2-3 and I'm trying to determine how to wire this lamp:

which is ground, hot and common....



Any help or suggestions appreciated.


	


A schematic for the fixture can be found at:



http://aeroelectric.com/Pictures/Lighting/PTT_Dim_Fixture.jpg



An exemplar application can be found in:



http://www.aeroelectric.com/articles/grndpwr.pdf

        Bob . . .



        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------

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etienne.phillips(at)gmail
Guest

Posted: Wed Aug 27, 2008 9:27 pm Post subject: Push-to-Test Lamp

On 28 Aug 2008, at 5:01 AM, Robert L. Nuckolls, III wrote:

 	  Quote: 	
		  

 An exemplar application can be found in:



 http://www.aeroelectric.com/articles/grndpwr.pdf

        Bob . . .




	


Hi Bob



Just a question. From my understanding, looking at this doc and the  

attachment from Don Curry, it looks as though pin 1 is common, 2 is  

normal and 3 is engaged on push. In your wiring, the bulb will only  

light up when external power is applied, which is great. What happens  

though when the bulb doesn't light up , and there's supposedly  

external power applied? There are only 3 possibilities: there is a  

problem with the external power, the bulb has popped, or the circuit  

breaker is not closed. In the first 2 cases, pushing the lens will  

not make the bulb light up.



Would it not be better to wire the bulb so that it allows better  

fault-tracing? My suggestion would be pin 1 to ground, pin 2 to the  

high voltage side of the contactor coil (where pin 1 is connected on  

your diagram), and pin 3 to a fuse then onto the battery bus (or any  

bus that would normally be powered when you'd want to use external  

power).



The behaviour of the light would change though:

If there is external power, the lamp will light up with the switch in  

either position, indicating external power is available for use

If there is no external power getting in (incorrect polarity or  

broken power supply) the bulb will not light

To test the bulb at any time, with or without external power applied,  

push the lens



What do you think? Am I smoking my socks?



Thanks

Etienne

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mrspudandcompany(at)veriz
Guest

Posted: Thu Aug 28, 2008 4:03 am Post subject: Push-to-Test Lamp

 	  Quote: 	
		  Bob:



I've purchased 2 Push-to-Test Lamps: MS25041 (amber) for my Low Voltage

Warning Lamp and another one (blue) for Low Oil Pressure.  The lamps have3

tabs, numbered 1-2-3 and I'm trying to determine how to wire this lamp:

which is ground, hot and common....



Any help or suggestions appreciated.


	


A schematic for the fixture can be found at:



http://aeroelectric.com/Pictures/Lighting/PTT_Dim_Fixture.jpg



An exemplar application can be found in:



http://www.aeroelectric.com/articles/grndpwr.pdf

        Bob . . .



   It looks like the test lamp function will not work on the gndpwr.pdf

drawing.  When ground power is removed there is no power to test lamp.

To wire a low oil pressure switch:  assuming the switch is normally open and

goes to ground, connect pin 1 to fused 12V, pin 2 (normally closed) to the

oil pressure switch, and pin 3 to ground.



Roger

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nuckolls.bob(at)cox.net
Guest

Posted: Thu Aug 28, 2008 4:55 am Post subject: Push-to-Test Lamp

At 07:59 AM 8/28/2008 -0400, you wrote:

 	  Quote: 	
		   >Bob:

 >

 >I've purchased 2 Push-to-Test Lamps: MS25041 (amber) for my Low Voltage

 >Warning Lamp and another one (blue) for Low Oil Pressure.  The lamps have3

 >tabs, numbered 1-2-3 and I'm trying to determine how to wire this lamp:

 >which is ground, hot and common....

 >

 >Any help or suggestions appreciated.



A schematic for the fixture can be found at:



http://aeroelectric.com/Pictures/Lighting/PTT_Dim_Fixture.jpg



An exemplar application can be found in:



http://www.aeroelectric.com/articles/grndpwr.pdf

         Bob . . .



    It looks like the test lamp function will not work on the gndpwr.pdf

drawing.  When ground power is removed there is no power to test lamp.


	


   Correct . . . it also shows that no ground power is applied.

   The idea here is that the pilot can know that ground power

   is available before actually applying it to the airplane.



   The PTT function can be used for more purposes that to

   query condition of the lamp. I've used these fixtures as

   push-button, lamp-holder combinations wherein the NO contact

   of the fixture is used to signal a circuit to do a self-test

   routine that ends with the lamp responding in some prescribed

   manner. I've also used the contact to start an auto-terminating

   operation . . . like trigger a timer on a bilge pump in a

   sea-plane. It runs for a period of time (light is lit) and then

   shuts off (light goes out).

 	  Quote: 	
		  To wire a low oil pressure switch:  assuming the switch is normally open and

goes to ground, connect pin 1 to fused 12V, pin 2 (normally closed) to the

oil pressure switch, and pin 3 to ground.


	


   Yup, that works!



   Bob . . .

        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------

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nuckolls.bob(at)cox.net
Guest

Posted: Thu Aug 28, 2008 5:16 am Post subject: Push-to-Test Lamp

At 07:24 AM 8/28/2008 +0200, you wrote:

 	  Quote: 	

<etienne.phillips(at)gmail.com>

On 28 Aug 2008, at 5:01 AM, Robert L. Nuckolls, III wrote:

>

>An exemplar application can be found in:

>

>http://www.aeroelectric.com/articles/grndpwr.pdf

>        Bob . . .

Hi Bob

Just a question. From my understanding, looking at this doc and the

attachment from Don Curry, it looks as though pin 1 is common, 2 is

normal and 3 is engaged on push. In your wiring, the bulb will only

light up when external power is applied, which is great. What happens

though when the bulb doesn't light up , and there's supposedly

external power applied? There are only 3 possibilities: there is a

problem with the external power, the bulb has popped, or the circuit

breaker is not closed. In the first 2 cases, pushing the lens will

not make the bulb light up.

Would it not be better to wire the bulb so that it allows better

fault-tracing? My suggestion would be pin 1 to ground, pin 2 to the

high voltage side of the contactor coil (where pin 1 is connected on

your diagram), and pin 3 to a fuse then onto the battery bus (or any

bus that would normally be powered when you'd want to use external

power).

The behaviour of the light would change though:

If there is external power, the lamp will light up with the switch in

either position, indicating external power is available for use

If there is no external power getting in (incorrect polarity or

broken power supply) the bulb will not light

To test the bulb at any time, with or without external power applied,

push the lens

What do you think? Am I smoking my socks?

   Not at all, you've perceived the possibilities for meeting

   different design goals. I explained the rationale for

   wiring as-shown in another posting. The suggestions you've

   made are equally valid. The differences are how the two

   circuits convey understanding . . . which assumes that

   the pilot KNOWS what to expect. This suggests that it's

   up to the tech-writer who crafts the POH to covey that

   understanding to the future users.

   Bob . . .

        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------

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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:

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Eric M. Jones

Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts

Posted: Thu Aug 28, 2008 6:28 am Post subject: Re: Push-to-Test Lamp

The US will join Australia and most other industrialized countries to discourage (or ban) the use of filament lamps in the next few years. Building an airplane with filament lamps seems to be a stretch...unless you are building one for a museum and you want it to be historically correct-along with the silk and gutta-percha insulation on the wires.



Another reason to ditch the filament lamps is seen when you look at the efficacy of filament lamps. Big lamps, especially halogens can be >20 lumens per watt, but the tiny indicator lamps are only 3-6 lumens per watt.



Although it seems to be a small thing, incandescent lamps are horribly

inefficient in small sizes. For example:GE# 67  (smallest bayonet instrument light) 13.5 Volts  Lamp Power 8W 0.59A 4 Candelas (about 50 lumens) Average Life 5000 Hours. 50 lumens/8W = 6 lumens per watt.



The similar LED is 25-100 lumens per watt, but the comparison doesn't stop there. The GE #67 incandescent is typically color-filtered so that only 10% of the emitted light is used, and it is isotropic so only 25% of THAT light goes where you need it. Furthermore using 10  GE #67 lamps (typical on a panel) is about 6 AMPS.....Astonishing load for no good reason.



And the LED will last FOREVER or 100,000 hours....whichever comes first...20X longer at least. So the LED (depending on how you figure...) is 1000X better deal.



You want to put in a Push-to-Test switch? You don't need any for the LEDs. You don't need a socket either, since the LEDs outlast the socket, the connectors, and Push-to-Talk mechanism. 



"Everything you've learned in school as 'obvious' becomes less and less obvious as you begin to study the universe. For example, there are no solids in the universe. There's not even a suggestion of a solid. There are no absolute continuums. There are no surfaces. There are no straight lines." 



-R. Buckminster Fuller

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

echristley(at)nc.rr.com
Guest

Posted: Thu Aug 28, 2008 6:59 am Post subject: Push-to-Test Lamp

Eric M. Jones wrote:

 	  Quote: 	
		   



 The US will join Australia and most other industrialized countries to discourage (or ban) the use of filament lamps in the next few years. Building an airplane with filament lamps seems to be a stretch...unless you are building one for a museum and you want it to be historically correct-along with the silk and gutta-percha insulation on the wires.



 Another reason to ditch the filament lamps is seen when you look at the efficacy of filament lamps. Big lamps, especially halogens can be >20 lumens per watt, but the tiny indicator lamps are only 3-6 lumens per watt.



 Although it seems to be a small thing, incandescent lamps are horribly

 inefficient in small sizes. For example:GE# 67  (smallest bayonet instrument light) 13.5 Volts  Lamp Power 8W 0.59A 4 Candelas (about 50 lumens) Average Life 5000 Hours. 50 lumens/8W = 6 lumens per watt.



 The similar LED is 25-100 lumens per watt, but the comparison doesn't stop there. The GE #67 incandescent is typically color-filtered so that only 10% of the emitted light is used, and it is isotropic so only 25% of THAT light goes where you need it. Furthermore using 10  GE #67 lamps (typical on a panel) is about 6 AMPS.....Astonishing load for no good reason.



 And the LED will last FOREVER or 100,000 hours....whichever comes first...20X longer at least. So the LED (depending on how you figure...) is 1000X better deal.



 You want to put in a Push-to-Test switch? You don't need any for the LEDs. You don't need a socket either, since the LEDs outlast the socket, the connectors, and Push-to-Talk mechanism. 

   

One more advantage with the LED is that you can put one anywhere you can 
	


drill a 3/16" hole, and even direct the light by angling the hole 

properly.  The standard 5mm LED is a push fit into a 3/16" hole.  Then 

you just need a small amount of room on the backside for hookup wires.  

If the mounting surface is thick enough and you're careful, you can use 

a #30 bit for the last 1/16" of the hole.  Then you don't even need a 

bevel.  You wind up with a nearly hidden indicator or spot illuminator.  

The push fit will keep it in place, but a dollup of shoo-goo is good for 

peace-of-mind.



No way you could do that with the GE #67.  It needs a special socket to 

get rid of all that heat.

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