Question 31General Subjects - Assistant Engineer

The correct answer is A) allow for longitudinal expansion of the crankshaft as the unit warms up. Tapered roller bearings used in the main bearings of a reciprocating air compressor are designed with a 'cold' end clearance to accommodate the longitudinal expansion of the crankshaft as the engine warms up during operation. This end clearance allows the crankshaft to expand without binding or putting excessive stress on the bearings. The other options are incorrect because: B) torsional vibration is not the primary reason for the end clearance, C) the end clearance is not to prevent longitudinal thrust, and D) the clearance is not specifically for crank web deflection.