Question 30 3AE02 - Third Assistant Engineer (Alt)

The Correct Answer is D. **Why option D ("replace the entire belt set") is correct:** In a multiple V-belt drive system (where two or more belts share the load), the belts wear simultaneously during operation. If only one belt is replaced, the new belt will be shorter and less stretched than the older, worn belts. Consequently, the new belt will carry a disproportionately higher share of the load, causing it to fail prematurely. Additionally, the uneven load distribution can lead to vibration and inefficiency in the drive system. To ensure the load is distributed evenly across all belts and maximize the lifespan of the drive, the standard maintenance practice is to replace all belts as a matched set. **Why each of the other options is incorrect:** * **A) season the new belt prior to installation:** Belts do not require "seasoning" (a term sometimes used for preparing other materials like leather or wood). Modern V-belts are designed for immediate installation. * **B) ensure the proper belt dressing is applied:** Belt dressing is generally discouraged for modern V-belts. It can attract dirt, cause slippage problems, and potentially damage the belt material over time. Modern V-belts are designed to grip the sheaves without additives. * **C) ensure the seasoned belts are reinstalled in their proper sequence:** While reinstalling used belts in their original orientation *might* be relevant if the drive were asymmetrical and the belts were merely being removed temporarily, it completely ignores the primary problem of mismatching a new belt with worn belts. If a replacement is needed due to failure or wear, the entire set must be replaced, making sequencing irrelevant.