Thermal Movement

    When machinery is operating the moving parts cause friction that in turn creates heat buildup causing the machinery to expand.  This expansion in the machinery is called Thermal Growth.   The amount of movement can be predicted when you know the machinery's material, temperature change, and the distance between shims and shaft centerline.

Calculating Thermal Movement

Graphing Thermal Movement
      Most machinery must be misaligned cold so that the shafts will be collinear during normal operating conditions.  Graphing the move above shows us that the pump does not move (no change in temperature) and the motor rises an estimated .004" (3.53 mils)

Pump stays the same
Motor rises .004" at both feet

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