Question 662Steam Plants - Assistant Engineer

The correct answer is D) Insufficient bearing crush. The split-type, precision insert, main bearing relies on the proper amount of bearing crush to secure it in place and prevent it from rotating with the journal. Insufficient bearing crush, which refers to the clamping force applied to the bearing by the bearing cap, can allow the bearing to shift and the dowel or locking lip to shear, leading to bearing rotation. The other options are incorrect because they do not directly impact the bearing crush. Short periods of above normal operating speeds, excessive bearing bolt torque, and unequal torque to bearing bolts may contribute to other bearing issues, but do not specifically cause the shearing of the dowel or locking lip due to insufficient crush.