Early Chinese MH lamp

The lamp shown here is representative of early Chinese metal halide lamps, designed and built with little regard and understanding for the science behind this technology. This HIE250/U/LU is essentially a cosmetic replica of a Tungsram daylight HgMIF, with a burner filled with a Na-Sc iodide mix instead of the Hungarian's Tl-Dy-Ho-Tm-Cs salt blend. As a result, the emitted light is much warmer, possibly around 3000 K, than that emitted by the original HgMIF. Unsurprisingly, the lamp design is unsuitable for a sodium-based fill chemistry: the unprotected side frame wire, the evacuated outer bulb, and the burner mounting straps located so close to the electrodes, will all cause a very rapid sodium loss from the quartz arc tube. While this issue was addressed and solved in the West during the 1960s, this critical aspect of the MH lamp design was ignored entirely here, 30 years after practical solutions were developed and patented. Interestingly, and perhaps in a bid to extend the lamp life, a significant amount of cadmium was dosed in the arc tube. This transition metal may work as an iodine getter, which would mitigate the negative effect of sodium loss on the lamp chemistry. Nonetheless, a short service life is still expected from this HIE250.

The lamp is designed with a low mercury dose for a 100-V operation, compatible with 250 W high-pressure sodium lamp ballasts. However, because of differences in electrical properties, the power dissipated in this metal halide lamp is 270 W (measured in the horizontal position, 262 W in the vertical position). The sodium-scandium salt fill used here seems to have be optimized for a gas-filled lamp because the higher burner temperature in vacuum causes quite a high sodium vapor pressure that results in a particularly low light color temperature with a strong pink hue. This characteristic contradicts the 4000 K CCT stamped on the lamp box (which, interestingly, is also designed like Tungsram's).

The manufacturer of this lamp is Changzhou Falida Electronics Co., Ltd. (Wujin Special Lighting Factory), a company that was founded in May 1986 in Changzhou (Niutang Town, Wujin City State, Jiangsu Province), China. They became Plus Lighting during the 1990s and were eventually renamed Plusrite Electric in the 2000s. In this process, the company grew to become a major manufacturer and distributor of lamps and lighting products, with a market presence spreading outside China. During this period of growth and expansion the quality of metal halide lamps produced by them improved significantly from the early type shown here.