A high pressure discharge lamp having overcurrent fuse protection.

摘要

A high pressure discharge lamp includes a resistive fuse (30) for overcurrent protection of its associated ballast, which fuse is connected electrically in series with the discharge vessel (1) of the lamp and continuously dissipates power during lamp operation. The resistive fuse is heated by passage of the operating current through the discharge vessel (1) during lamp operation to a temperature substantially controlled by the operating current. In response to an increase in the operating current to a predetermined overcurrent, the resistive fuse reaches a temperature such that it breaks and disconnects the discharge vessel from its source of electric potential within a predetermined time period. The fuse passes short-term high starting currents and does not disconnect the discharge vessel during each lamp start-up at least until the operating current reaches the predetermined over-current during lamp life.