Re: CFL effciency?

quoting:
>>>What is being described as a "hood resistor" may be a High-Low-Off
>>>switch which puts a diode in series with the socket in the Low 
>>>position.  My past two hoods have been equipped that way.
>>>
>>>What would half-wave dc due to a self-ballasted CFL?  Nothing good,
>>>probably.
>>
>>I disagree with Andrew completely. The electrolytic energy storage
>>capacitor used in CFLs is usually just big enough to maintain the
>>discharge during those portions of the half-cycle when the line
>>voltage is low. If the system is fed with a half-wave rectified,
>>complete half-cycles of the input wave will be missing. The lamp will
>>therefore go out 60 times a second, which will not only lead to lower
>>light intensity but much greater wear on the electrodes.
>
>  OK Vic, you made me test some integral-electronic-ballast CFLs with a 
>diode.  This is in the USA, where the line voltage is 120V AC at 60 Hz.
>
>
>  Worked well with a diode - minimal dimming and no noticeable flicker:
>(CAUTION - I do not guarantee reliable duplication of my results!)
>
>Sylvania spiral 13 watt
>Sylvania Dulux EL (integral ballast doubletwintube) 7 watt - and I suspect
>   some versions and/or higher wattages may not do so well
>Sylvania Dulux EL 23 watt (integral ballast tripletwintube) - an older 
>   version, and I suspect some versions may not do so well
>Lights of America "Q-Lites" 27 watt quad-tube with modular electronic 
>   ballast (an older version)
>
>
>  Worked with a diode - dimmed a little noticeably, flickered visibly at 
>the line frequency, but basically worked and the arc did not drop out nor 
>revert to a glow discharge between peaks:  CAUTION - I do not guarantee 
>reliable duplication of my results!
>
>Commercial electric mini spiral 14 watt
>Commercial electric spiral 19 watt 6500K/daylight
>GE spiral 26 watt
>
>
>  By-and-large did not work, as in did not glow at all, glowed only at one 
>end, or lit at greatly reduced brightness with severe flicker with the 
>arc not maintaining throughout the AC cycle, or blinked at a frequency 
>lower than the line frequency:
>
>Commercial Electric spiral 42 watt
>Westinghouse spiral 20 watt "medium white" 3500K
>Sunbeam spiral (of the larger of 2 sizes that I saw) 24 watt
>Philips SLS 25 watt (triple arch) - may or may not do better in lower 
>   wattages
>Fieldbreeze (dollar store type) 13 and 18 watt, phosphor largely "warm 
>   white" "halophosphate" that traditionally has CRI of 53
>Volt Power (dollar store 6500K/daylight type) 11 watt
>
>  I did see a trend of higher amps (and lower power factor) corresponding 
>with better ability to work with halfwave rectification.
>


I just connected a LOA 18w CFL to a diode to see what happenes.  It appears 
normal light output, but extremely flickery.  Power factor was reduced.  The 
fluorescent tube itself was still receiving high frequency from the ballast. 
 It's flickery becuase the DC is switching on and off 60 times per second.  
Since it's the same thing as powering on and off 60 times per second, it 
can't be good for the ballast and the electrodes will probably wear faster.  
It is not the same thing as a magnetic ballast operated with a diode, since a 
magnetic ballast will output true 60 pulses per second, while an electronic 
ballast will still output HF while the DC current is ON.  However a good 
electronic ballast wil have a large enough capacitor so that the OFF time 
of the pulsed DC will be neatly smoothed out, and not flicker.