| 2010-05-20: OP-110 FAQ by Ron Vaickauski (Underwriters Laboratories, Inc.) |
As convenor of CTL WG1, I occasionally receive telephone calls or emails asking basic questions about CTL-OP-110. These questions typically are asked by either CB Assessors or CB test laboratories. I thought it might be useful to review some the most commonly asked questions as a supplement to the CTL WG1 report presented at the 46th CTL meeting. Article |
| 2008-01-29: Energy efficiency through sustained lamp performance by Dhananjoy Biswas (CBTL Electronics Regional Test Laboratory (East)) |
| High Intensity Discharge (HID) Lamp such as Sodium Vapour and Metal Halide has an average life of about 20000 hours in Europe and USA compared to 8000 hours in many parts of Africa, Asia including India. Lamp failures are observed either due to burning hours of lamp or due to no of switching cycle. In Europe and USA Lamp failures are mainly due to ageing / burning hours of lamp. Whereas in many parts of Africa, Asia including India lamp failures are due to number of switching cycle (ON/OFF) as a result of frequent power supply interruption(Average 3 switching per 12 hours of operation). Starting a HID lamp require a high amplitude high energy pulse to ionize mercury vapour with other halides. The high amplitude high energy pulse are provided by an ignitor for a duration of 3 to 5 minutes till lamp current is almost 90 percent of nominal value /110 percent of nominal lamp voltage. This high amplitude high energy pulses causes sputtering /erosion of lamp electrode, thus reducing lamp efficacy as well as switching life of a lamp. Luminous efficacy depreciates to below 40 percent of 100 hour value in 8000 hours in India and in 20000 hours in Europe and U.S.A .It is a well known fact that in sports and security lighting where high voltage ignitor pulses in the order of 20 KV are used for instant switching on HID lamps , lamp life decreases to few cycles. It is observed through experimentation that when HID lamp such as High Pressure Sodium Vapor and Metal Halide lamps are ignited with Pulse ignitors inbuilt into luminaire having energy content 2.25 mJ for 100 cycles , luminous efficacy depreciation is 8 to 10 percent of 100 hour value for sample size of 10. However Maximum luminous efficacy depreciation observed 2 percent, when same rating lamps are subjected to ignition for 100 cycles with ignitors having energy content below critical limit under same condition. This arrest of depreciation of luminous efficacy is due to arrest of erosion of tungsten electrode. Depending upon arc tube length, critical energy of discharge tube will vary. Sustained illumination with ageing of lamp is possible with correct determination of critical energy and starting lamp with ignitor pulses below critical energy. Sustained illumination of lamp will enable to consider higher maintenance factor for illumination design, thereby lower power HID lamp can be used in place of higher power lamp. It is estimated to save 33 percent energy. Sustained illumination of lamp also contributes in arrest of global warming by arresting heat radiation from millions of aged light sources. Article |
| 2007-11-08: Prevention of early switching life failure of Metal Halide and other HID lamp- Invention of Dragon Kink effect by Dhananjoy Biswas (CBTL Electronics Regional Test Laboratory (East)) |
| Frequent power supply interruption is very common in most parts of Asia and Africa. Declared lamp life is based on one switching in 24 hours as per IEC 61167 for M.H lamp and IEC 60662 for SON lamp. Minimum pulse amplitude and energy required for ignitor pulses has been specified in IEC 60926/927 specification for starting a lamp. As on date there is no higher limit of ignitor pulse energy in IEC 60926/927 specification. Neither the lamp manufacturers specifies maximum pulse energy which MH/SON lamp could be subjected so that switching life does not get affected. With energy conservation in mind lamps are also switched on/off repeatedly to save power. Repeated switching on/off with ignition pulses of energy content reaching lamp greater than 0.75 mJ (may vary depend on discharge tube) reduces switching life of lamp. Maximum energy of ignitor pulse which lamp can be subjected for switching on/off without sacrificing switching life is termed as critical energy(Le). Article |
| 2007-05-04: Tripping Current and Short Circuit Current of High Voltage Tester by Xu Zhezhun & Wang Keqin (CBTL STLEA) |
| Tripping current and short circuit current are important technical specifications of high voltage tester, and frequently required to be verified according to the stipulation of relevant test standard during laboratory assessment. However, it is in difficulty to verify the short circuit current by direct measurement because of the existence of overload protection. A indirect calculation method for short circuit current is introduced in this article. |
