Plant Operator Selection System Test Plant Operator Selection System Mechanical Concepts 3

Question 1

A compound gear train has a driving gear with 10 teeth meshed with an intermediate gear of 50 teeth. The intermediate gear is on the same shaft as a 10-tooth gear driving a final gear with 40 teeth. What is the overall gear ratio (input to output)?

Accepted Answer

20:1

Answer

Overall ratio = (50/10) × (40/10) = 5 × 4 = 20:1, meaning the output shaft turns once for every 20 input turns.

Question 2

Which type of bearing is specifically designed to handle axial (thrust) loads along a shaft's axis?

Accepted Answer

Thrust bearing

Answer

Thrust bearings are engineered to support loads parallel to the shaft axis, unlike radial bearings that handle perpendicular loads.

Question 3

A manometer reads 25 inches of water column. Approximately how many PSI does this represent?

Accepted Answer

0.9 PSI

Answer

Water column converts at 27.7 inches H₂O per PSI, so 25 ÷ 27.7 ≈ 0.9 PSI.

Question 4

In a steam system, which device removes condensed water (condensate) from the steam lines without allowing steam to escape?

Accepted Answer

Steam trap

Answer

A steam trap automatically drains condensate while keeping steam in the system, preventing water hammer and efficiency loss.

Question 5

A centrifugal pump is running but producing no flow. Which condition is MOST likely the cause?

Accepted Answer

The pump is air-bound (cavitating on air)

Answer

If a centrifugal pump is air-bound, it cannot create suction because air does not produce enough centrifugal force to move liquid.

Plant Operator Selection System Test Practice Test

Plant Operator Selection System Test Practice Test

Plant Operator Selection System Test Plant Operator Selection System Mechanical Concepts 3