CMRT Equipment Reliability 2

Question 1

A pump has an MTBF of 2,000 hours and an MTTR of 8 hours. What is its inherent availability?

Accepted Answer

99.6%

Answer

Inherent availability = MTBF / (MTBF + MTTR) = 2000 / 2008 ≈ 99.6%.

Question 2

Which reliability metric measures the average time a system operates before failing?

Accepted Answer

MTBF

Answer

MTBF (Mean Time Between Failures) measures average operating time between consecutive failures for repairable systems.

Question 3

If a component has a constant failure rate of 0.0005 failures/hour, what is its reliability after 1,000 hours?

Accepted Answer

60.7%

Answer

R(t) = e^(-λt) = e^(-0.0005 × 1000) = e^(-0.5) ≈ 0.607 or 60.7%.

Question 4

A system has three components in series with reliabilities of 0.95, 0.90, and 0.98. What is the system reliability?

Accepted Answer

0.837

Answer

Series system reliability = R1 × R2 × R3 = 0.95 × 0.90 × 0.98 ≈ 0.837.

Question 5

What does the 'bathtub curve' infant mortality region indicate about equipment failure?

Accepted Answer

Failures decrease over time due to early defect elimination

Answer

The infant mortality region shows a decreasing failure rate as weak components fail early and are removed from service.

(CMRT) Certified Maintenance and Reliability Technician Practice Test