In a normal bearing, if there is a defect on the outer race, which observation would be expected?

In the case of a defect on the outer race of a bearing, the expected observation is a non-synchronous peak with no sidebands. The reason this is correct relates to the nature of how defects in bearings manifest in vibration analysis.

When a defect, such as a crack or pit, is present on the outer race of a bearing, it creates a distinct pattern in the generated vibration signals as the rolling elements pass over the defect. This results in a vibration frequency that is related to the rotation of the shaft but does not correspond directly to the normal operating frequency related to the rotation of the rolling elements themselves. As a result, you will see a peak that appears at a frequency that is not harmonically related to the fundamental running frequency of the bearing, leading to it being identified as non-synchronous. Since an outer race defect typically does not produce regular pulsations associated with the rolling elements in the same way a defect on the inner race might (which could generate sidebands), the absence of sidebands further confirms the nature of the defect.

The other answer choices present scenarios that would not accurately describe the behavior of a bearing with an outer race defect. For instance, a synchronous peak with sidebands would typically be linked with defects on the inner race