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Wig Wag and keep warm

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fvalarm(at)rapidnet.net
Guest

Posted: Tue Oct 30, 2007 7:33 pm Post subject: Wig Wag and keep warm

Bob,



When using the B&C SSF-1 wigwag flasher with two 100watt Halogen bulbs, can

I add a keep warm circuit in parallel with the flasher?  If so would this

just consist of a nominal resistor (say 1K ohm) and some light gauge wire

(say 22 awg)?  



If not, can you suggest a better alternative?



Thanks



Bevan

nuckolls.bob(at)cox.net
Guest

Posted: Tue Oct 30, 2007 9:04 pm Post subject: Wig Wag and keep warm

At 08:30 PM 10/30/2007 -0700, you wrote:



 	  Quote: 	
		  

Bob,



When using the B&C SSF-1 wigwag flasher with two 100watt Halogen bulbs, can

I add a keep warm circuit in parallel with the flasher?  If so would this

just consist of a nominal resistor (say 1K ohm) and some light gauge wire

(say 22 awg)?



If not, can you suggest a better alternative?



Thanks


	


   Keepwarm is not necessary/useful for halogen lamps.

   They take so long to cool down that after the first

   turn-on, the inrush for successive flashes of the

   wigwag is insignificantly higher than normal

   operating current.



   Bob . . .



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

        ( "Problems are the price of progress. )

        ( Don't bring me anything but trouble. )

        ( Good news weakens me."               )

        (              -Charles F. Kettering-  )

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

fvalarm(at)rapidnet.net
Guest

Posted: Wed Oct 31, 2007 7:45 am Post subject: Wig Wag and keep warm

Bob,



OK, very good to know and easy to implement. Thank you very much.



Bevan

RV7A wiring 



--

Tony Cann

Joined: 10 Jan 2006
Posts: 3
Location: Fair Oaks, CA

Posted: Wed Oct 31, 2007 8:33 pm Post subject: Wig Wag and keep warm

Is there any harm in wig-wagging halogen lamps (for the safety aspect)?  Does it shorten lamp life?  If not, is the SSF-1 the correct circuit?  

   

Thanks  

Tony  

   

        [quote][b]

nuckolls.bob(at)cox.net
Guest

Posted: Thu Nov 01, 2007 4:41 am Post subject: Wig Wag and keep warm

At 09:31 PM 10/31/2007 -0700, you wrote:



 	  Quote: 	
		  Is there any harm in wig-wagging halogen lamps (for the safety 

aspect)?  Does it shorten lamp life?  If not, is the SSF-1 the correct circuit?



Thanks



Tony


	


    Temperature cycling by flashing any incandescent lamp

    shortens service life . . . but then, using a drill

    bit to drill holes also dulls the cutting edges;

    drilling steel as opposed to wood makes for fewer

    nice holes.



    The halogen lamps are MUCH more robust than their

    ancestors, hence a lot more tolerant of vibration

    and operating cycles. I think it likely that

    most owner/operators of halogen fitted aircraft

    will operate the same bulbs for the lifetime of

    the airplane.



    If using the Wig-Wag system by any supplier is

    a demonstrable reduction of in-flight risks, then

    I'll suggest concerns for service life become

    insignificant. Any Wig-Wag system including the

    SSF-1 flasher from B&C is worthy of consideration.



    Bob . . .

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

        ( "Problems are the price of progress. )

        ( Don't bring me anything but trouble. )

        ( Good news weakens me."               )

        (              -Charles F. Kettering-  )

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

echristley(at)nc.rr.com
Guest

Posted: Thu Nov 01, 2007 5:52 am Post subject: Wig Wag and keep warm

Tony Cann wrote:

 	  Quote: 	
		  

 Is there any harm in wig-wagging halogen lamps (for the safety 

 aspect)?  Does it shorten lamp life?  If not, is the SSF-1 the correct 

 circuit?



  



 Thanks



 Tony



Actually, there can be, depending on how it's done.
	




The halogen works by getting a tungsten filament to glow.  Part of the 

filament turns to a gas within the bulb, and will settle on the inside 

of the glass when the bulb is powered off.  The next time the bulb is 

turned on, the filament gets hot enough to burn the layer of deposit off 

the glass (turning it back into a gas).  If you continuously turn it on 

without letting it warm to operating temperature, the deposit layer gets 

thicker and thicker.  The bulb will get darker and darker, and the fix 

is simply to let the bulb come up to operating temps.  The burn off 

process can take a while if the bulb has been abused in this way.



OTOH, there's not point in doing this to a halogen bulb.  The filament 

in a normal bulb is a very fine wire, that breaks easily and vibrates 

like mad.  The filament in a halogen is a chunk of tungsten.  You're 

more likely to break the glass bulb than the filament.

rv-9a-online(at)telus.net
Guest

Posted: Thu Nov 01, 2007 8:52 am Post subject: Wig Wag and keep warm

I found that the flash rate of the SSF-1 was a bit too fast for my lamps to

come up to full brightness.  It's a simple mod to replace the internal

electrolytic capacitor with one of higher value (I think I doubled the value

of mine).  My issue may have been exacerbated by the inrush current limiters

(ntc thermistors) that I have in series with the lighting circuits.



Vern Little

nuckolls.bob(at)cox.net
Guest

Posted: Thu Nov 01, 2007 9:26 am Post subject: Wig Wag and keep warm

At 09:50 AM 11/1/2007 -0700, you wrote:



 	  Quote: 	
		  

<rv-9a-online(at)telus.net>



I found that the flash rate of the SSF-1 was a bit too fast for my lamps to

come up to full brightness.  It's a simple mod to replace the internal

electrolytic capacitor with one of higher value (I think I doubled the value

of mine).  My issue may have been exacerbated by the inrush current limiters

(ntc thermistors) that I have in series with the lighting circuits.


	


   Good data point Vern. I'd heard that before

   but without specifics as to what the builder

   did about it. I think he pitched the SSF-1 flasher

   and substituted something else.



   I don't think inrush limiters would affect timing

   on this device . . . but it's certain that the

   inrush limiters have more to do with mitigating

   initial turn-on glitches to the bus than for

   extending bulb life.



   Bob . . .



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

        ( "Problems are the price of progress. )

        ( Don't bring me anything but trouble. )

        ( Good news weakens me."               )

        (              -Charles F. Kettering-  )

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

klehman(at)albedo.net
Guest

Posted: Thu Nov 01, 2007 10:11 am Post subject: Wig Wag and keep warm

My 35 watt halogens are still happily wagging at 140 hours which is one 

cent per hour bulb cost even if they both quit on the next flight.  I 

haven't checked them for tungsten deposit darkening recently but I do 

know a very particular person who replaces automotive halogen headlights 

every year or two because of darkening.  I've never found it to be much 

of an issue, even on a car that uses a resistor to reduce the current in 

the daytime, but measurements might tell a better story. FWIW my opinion 

is that thermistor inrush current limiters reduce maximum brightness 

enough that I avoid them with halogens since these bulbs have much 

extended lives anyway compared to the old 320 hour automotive sealed 

beams. I won't purchase extended life household incandescents either 

(except for locations with difficult access) as they increase the total 

cost per lumen significantly due to less efficiency.

Ken

Ernest Christley wrote:

 	  Quote: 	

 <echristley(at)nc.rr.com>

 Tony Cann wrote:

>

> Is there any harm in wig-wagging halogen lamps (for the safety 

> aspect)?  Does it shorten lamp life?  If not, is the SSF-1 the 

> correct circuit?

>

>  

>

> Thanks

>

> Tony

>

 Actually, there can be, depending on how it's done.

 The halogen works by getting a tungsten filament to glow.  Part of the 

 filament turns to a gas within the bulb, and will settle on the inside 

 of the glass when the bulb is powered off.  The next time the bulb is 

 turned on, the filament gets hot enough to burn the layer of deposit 

 off the glass (turning it back into a gas).  If you continuously turn 

 it on without letting it warm to operating temperature, the deposit 

 layer gets thicker and thicker.  The bulb will get darker and darker, 

 and the fix is simply to let the bulb come up to operating temps.  The 

 burn off process can take a while if the bulb has been abused in this 

 way.

 OTOH, there's not point in doing this to a halogen bulb.  The filament 

 in a normal bulb is a very fine wire, that breaks easily and vibrates 

 like mad.  The filament in a halogen is a chunk of tungsten.  You're 

 more likely to break the glass bulb than the filament.

rv-9a-online(at)telus.net
Guest

Posted: Fri Nov 02, 2007 9:48 am Post subject: Wig Wag and keep warm

Thanks Bob.  



I put the inrush limiters in circuit as a switch saver as opposed to a lamp

saver.  I've had two Carling switch failures in the first 100 hours-- one

Master Switch and the other in my Strobe circuit.  The Master had loose

rivets that hold the fast-on tabs, while the Strobe switch (which also had a

loose rivet) overheated and cooked one terminal. Switch resistance had

increased significantly, and I believe the Strobe PSU draws more current at

lower voltages, leading to a thermal runaway in the switch.



Since then, I've inspected all of my switches for loose rivets and put the

inrush current limiters on the landing/taxi lights.  I did return one of the

switches to the vendor but never heard back with a failure analysis.



The inrush limiters don't have much effect on maximum lamp brightness, but

slowing the wig-wag flasher down sure did. 



Vern



--

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