Bias the Cold Misalignment?

When the machine go in actual operation, under that condition the machine centerline will not be same as the cold condition.

Thermal expansion, journal lift etc all come in picture.

So the designer calculate the exact amount of misalignment to be maintained in cold condition so that in the hot condition there is no misalignment.

Eg in some Turbines we maintain a mis-alignment of 0.30±0.02 vertically downwards.

Similarly even axial gaps are maintained in the coupling so that in hot condition there is neither excess gap nor a thrust.