Still blowing after all these years

In the heart of Germany`s Black Forest, a pair of fans has been operating continuously for more than 20 years. The fans, at fan-maker Papst`s headquarters, have been running at 40°C on a once-a-month stop-start cycle, and have already clocked up more than 175,000 operating hours.

Over that time, the shafts of the 48V DC and 220V AC fans have made more than 30 billion revolutions and the outer edges of their blades have travelled more than 13 million km - equivalent to 30 trips to the moon. The fans have not needed any maintenance during their marathon spin.

When fans do fail, it is usually due to a combination of mechanical stresses, and high temperatures that degrade the bearing lubricant. According to Papst, DC fans usually last longer than AC models, with typical life expectancies of 35,000-80,000 hours, depending on the type and the operating conditions.