 |
 |
 |
|
|
|
|
|
| What exactly is "acceleration" ? Acceleration measures the rate of change of velocity (how quickly the velocity is changing). There are two methods of applying an acceleration force (deceleration is simply a negative acceleration): |
| 1. A Pushing Action similar to you compressing a spring between your hands. The more you compress a spring, the more force it pushes back with. If you were to push a pillow block bearing away from its "at-rest" position, it would push back. If you went farther, it would push back more. That is a simple way to visualize the acceleration force we are measuring. The amount of movement at a particular frequency is a combination of the force being generated by the rotation of the rotor (unbalance, for intsance, is simply a centrifugal force due to a heavy spot on a rotor), the stiffness and masses of the materials and structure involved and other variables that are structure related. |
| 2. A Striking Action similar to you hitting a nail with a hammer. This action can be extremely destructive since it can cause structural flaws (cracks, for instance) to develop. Consider a jack hammer. It is the striking action that breaks up the cement. One example In the case of a rolling element bearing, a rolling element may pass a defect on one of the races and an impact results similar to hitting a pothole with your car. |