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The French manufacturer Compagnie des Lampes was one of the early pioneers in the development of metal halide lamps, but only ever made high power versions of 400W to 2000W. Metal halide technology becomes progressively more difficult to master at lower powers, and the company sourced in such products from Philips, with whom it had a technical affiliation for many years.
The Mazda MAI-series employs the same chemistry as GE's original metal halides, being dosed with the iodides of sodium, indium and thallium - plus lithium as an impurity from the quartz. The influence from Philips is evidenced by the unusual neon-argon filled arc tubes, and neon-nitrogen filled outer envelopes, which facilitates ignition at lower voltages. Owing to the high thermal conductivity of neon, the arc tube is unusually small for its power rating. Sodium loss by the photoelectric effect is reduced by another Philips concept, using a steatite tube around the support frame.
This particular lamp is an unusual design unique to CdL. Whereas most manufacturers have a rather large aspect ratio for their 1000W arc tubes, CdL simply departed from its 2000W 380V arc tube and reduced the length to lower lamp voltage while operating at similar current. This has the advantage of allowing universal burning, but presumably at the expense of reduced lifetime. The arc tube has been fabricated from three pieces of quartz, and the outer bulb employs a zirconium-aluminium getter for hydrogen. The cap is of a high quality design with porcelain insulator to better withstand the high ignition voltages. Following Philips' 1982 takeover of CdL-Mazda, this unusual lamp was phased out and replaced by the 1000W HPI-T long arc version. |