ETL 1110-2-560
30 Jun 01
Table D-2 (Concluded)
Weibull
Standard
Index β
Failure Mode
Life
Displacement/seizing/adhesion:
Loosening
1.0
Inf
Misalignment
1.0
Inf
Seizing
1.0
Inf
Setting
1.0
Inf
Sticking
1.0
Inf
Shifting
1.0
Inf
Turning
1.0
Inf
Examples:
Loosening (locking fasteners)
1.0
Inf
Loosening (bolts)
1.0
Inf
Loosening
1.0
Inf
Misalignment (process pump set)
2.0
1.5-3.0Y
Seizing (linkages)
1.0
Inf
Seizing (components subject to contamination
1.0
Inf
or corrosion)
Shifting (unstable design)
1.0
Inf
Leakage:
Joints with relative movement
1.5
3.0M-4.0Y
Joints without relative movement
1.0
16.0Y
Mechanical seal faces
0.7-1.1
0.5-1.5Y
Clogging
1.0
Inf
Coking
2.0
0.5-3.0Y
Dirt accumulation
2.0
0.5M-3.0Y
Fouling
1.0
Inf
Plugging
1.0
Inf
Examples:
Fouling gas compressor
3.0
1.5-5.0Y
Plugging of passages
1.0
Inf
with moving medium
Plugging of passages
1.0
Inf
with nonmoving medium
Conductor Interruption
Flexible cable
1.0
Inf
Solid cable
1.0
Inf
Burning through Insulation
Motor windings
1.0
16Y
Transformer windings
1.0
16Y
(Sheet 3 of 3)
D-7
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