The generator shares the same issues as the engines, but the genset's power-generating equipment also needs to stay cool. "Generator engines use water to cool themselves, but most [electrical] components use airflow," says Mark Turpin, a mechanical engineer with Cummins Power Generation. (www.cumminsonan.com) "They're designed to last 20,000 hours or more, but if the alternator runs hot enough, that could reduce to 5,000, 100, or even two hours." Generators cool themselves with adequate air, but Turpin says neglected ventilation systems are common, particularly when generators are located outside of the main engineroom. Blocked sound-enclosure vents are another. "I've seen boxes stacked against the inlet ducts, or loose equipment that falls and blocks the airflow," he says. Loose sound-deadening insulation can disrupt airflow inside generator sound enclosures or block air-intake vents. Sound-enclosure air dams, which separate cool incoming air from hot air discharged through the alternator, should be checked as well.