Design Guide
Page 125
... a minimum useful lifetime of 57,000 hours. • In addition to passing the environmental reliability tests described in Sections 5.2 and 6.3, the fan must be within spec for specified duty cycle In addition to comply with each cycle specified as 3 minutes on, 2 minutes off, at a temperature of the functional mechanical elements (ball...
... a minimum useful lifetime of 57,000 hours. • In addition to passing the environmental reliability tests described in Sections 5.2 and 6.3, the fan must be within spec for specified duty cycle In addition to comply with each cycle specified as 3 minutes on, 2 minutes off, at a temperature of the functional mechanical elements (ball...