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What are warm-up and restrike times for metal halide lamps?
Metal halide (MH) lamps do not achieve their full light output immediately after starting. Rather, they require a period of time-1 to 15 minutes-to reach 90% of their full light output. This period is called the warm-up (or run-up) time. After a lamp has been on for a period of time and then extinguished, it cannot be immediately turned back on. Before the lamp can be turned back on, the arc tube must have a chance to cool down or the lamp will not restart. This period of time is called the restrike time. Restrike times for traditional probe-start MH lamps can take 15 minutes or longer, but restrike times for pulse-start MH lamps are generally much shorter (see Figure 4). According to manufacturers' literature, restrike times for pulse-start MH lamps can be more than twice as fast as for probe-start MH lamps.
Figure 4. Warm-up/restrike times for probe-start and pulse-start technologies |
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