Page 295 - Improving Machinery Reliability

266 Improving Machinery Reliability

Table 5-5
MTBF Comparison for Direct-Drive Vs. Belt-Drive Blowers
(Based on Component Failure Rate Data from Table 5-2)
Direct-Drive Shows a 20% Higher Average MTBF

ave. MTEF 7 months 8.4 months

(text continted from page 263)

machine MTBF can thus be visualized and appropriate life cycle cost calculations
initiated.
Suppose we had a series of centrifugal pumps with typically estimated lives of 2.5
years for mechanical seals, 5 years for ball bearings, 7 years for couplings, and 15
years for shafts. In that case, the anticipated overall MTBF of these pumps will prob-
ably be reasonably close to the inverse of

If bearing housing seals (Figure 5-1 and pages 447-449) were to extend seal and
bearing lives to an estimated 3.5 and 10 years, respectively, the anticipated pump
MTBF could reasonably be expected to reach the inverse of