Content deleted Content added
reinserted reference to normal 5,000-hour 50-cent incandescent bulb (that some would like to pretend doesn't exist) |
added missing mention of AC vs. DC and inrush issues |
||
Line 329:
;Lifetime brightness:Fluorescent lamps get dimmer over their lifetime,<ref>{{cite web|url=http://www.rightlight6.org/english/proceedings/Session_8/Performance_Standard_and_Inspection_Methods_of_CFL/s08-2p013guan.pdf|format=PDF|title=Topic and Discussions on the Performance Standard and Inspection Methods of CFL|accessdate=2007-04-13}}</ref> so what starts out as an adequate luminosity may become inadequate. In one test by the US Department of Energy of 'Energy Star' products in 2003–4, one quarter of tested CFLs no longer met their rated output after 40% of their rated service life.<ref>{{cite web|url=http://www.osti.gov/bridge/servlets/purl/881039-K5YRuT/881039.PDF|format=PDF|title=Energy Star Lighting Verification Program (Program for the Evaluation and Analysis of Residential Lighting) Semi-annual report For the period of October 2003 to April 2004|accessdate=2007-04-13}}</ref><ref>{{cite web|url=http://mail.mtprog.com/CD_Layout/Day_2_22.06.06/1400-1545/ID133_Banwell_final.pdf|format=PDF|title=Quality Assurance in Energy Star Residential Lighting Programmes|accessdate=2007-04-13}}</ref>
;[[UV]] emissions: Fluorescent bulbs can damage [[paintings]] and [[textile preservation|textile]]s which have light-sensitive [[dyes]] and [[pigments]]. Strong colours will tend to fade on exposure to UV light. Ultraviolet light can also cause [[polymer degradation]] with a loss in [[mechanical strength]] and yellowing of colourless products.<ref>http://www.gcrio.org/UNEP1998/UNEP98p62.html</ref>
;incompatibility with DC fixtures: a 120V incandescent bulb can run on either 120VAC or 120VDC, while a 120V CFL may require 170VDC or it may explode when connected to DC (because of DC short paths). This poses a problem when DC is needed in order to achieve absolute silence, e.g., in recording studios.
;Large inrush currents: A 100W, 120V incandescent bulb requires a 10A current when cold, and 830mA thereafter. By contrast, a 25W CFL replacement can require a 20A inrush current to charge a large capacitor in bad CFL designs. For example, look at the circuit board shown above. Clearly you can see a 10uF capacitor on the input side. Now imagine connecting 2 or 3 of these bulbs to your mains via a little 2A relay -- something you could easily do with three 100W bulbs. The relay will weld closed after about 5 uses. Then you won't be able to turn the light off! The worst inrush is when the lamp is switched on at the peak of the cycle. Even though the continous RMS current is around 500mA (because of bad power factor, which is another story) you would need at least a 10A relay to switch a mere 25W CFL. SCRs that switch at zero-crossings are not an option in high-efficiency systems because of the 1.5V drop. MOSFETs are OK but very expensive. Therefore conventional fluorescent fixtures (or very, very expensive CFLs with good inrush limiter circuits) need to be used wherever efficiency and automatic switching are required.
==Efforts to encourage adoption==
| |||