“What are some common sources of non-passive bulb failure?”
One cause of non-passive bulb failure is often overcooling or undercooling of the bulb. Overcooling can prevent the bulb from reaching an optimal operating temperature and under cooling can allow the bulb to exceed a safe operating temperature and result in failure. Contributing factors include (but are not limited to) clogged fan filters, restricted air flow, a worn fan, an environment that is excessively cold, hot, or humid, or excessive air flow through the unit. In addition to over or undercooling, rapid temperature changes can also cause stress on the bulb. This can occur if the unit is in a warm environment and a nearby air conditioning duct or opened window allows chilled air to enter the unit.
Another common mistake is using the bulb over 2,000 hours. While it may be tempting to reset the hour meter after it indicates a necessary bulb change without actually changing the bulb, DO NOT RESET. Even if the unit still has sufficient intensity, NEVER do this. Eventually, most bulbs will fail in a non-passive manner if operated beyond 2,000 hours.
Excessive cycling can also cause bulb failure. During the bulb’s warm-up phase, the different coefficients of thermal expansion between the quartz and metal components in the bulb cause stress in the quartz. The more frequently a bulb is cycled (more than 1 power-up cycle per 8 hours), the more fatigue and stress are imparted to the bulb. Best practice is to leave the unit on as long as possible to avoid excessive power on-off cycling.
Vibrations, contamination from finger oil, or not providing proper air clearance are also common problems that can result in non-passive bulb failure.