NALMCO Certified Apprentice Lighting Technician (CALT) Practice Exam

If a lamp is rated at 20,000 hours at three hours per start, what is this lamp life based on?

1. Turned off and on quickly every three hours

2. Left on for three hours and off for 15-20 minutes

3. On for three hours and off for three hours

4. None of the above

The correct answer is: Left on for three hours and off for 15-20 minutes

The correct answer is based on the understanding that lamp life is typically quantified under specific operating conditions that account for how often a lamp is turned on and off. The rating of 20,000 hours at three hours per start suggests that the lamp is designed to be turned on for three hours at a time, with a consistent warm-up period or off-time afterward. In this case, option B outlines a scenario where the lamp is left on for three hours and then turned off for a duration that allows it to cool down, aligning with how many lamps are tested for longevity. This “cool down” period helps maintain the integrity and lifespan of the lamp. This understanding hinges on the fact that lamps undergo stress during the heating and cooling cycles associated with being turned on and off, influencing their life expectancy. The specification indicates that ratings like this assume a period of inactivity that ensures the lamp not only starts but also performs efficiently without overheating, which is common in standardized testing scenarios.