What is the general fault pattern in the velocity spectrum to an outer race?

The general fault pattern in the velocity spectrum for an outer race is characterized by a peak with no sidebands. This pattern occurs due to the nature of faults on the outer race of rolling element bearings. When a fault is present, such as a crack or spall, it can create periodic impacts as the rolling elements pass over the damaged area. However, unlike faults in other components, the outer race typically does not generate modulation effects that would result in sidebands around the fundamental frequency.

The presence of a peak with no sidebands indicates that the fault is generating a consistent repetitive signal without additional frequency components that would suggest interaction effects or cage influences. This is a key distinction in diagnosing faults, as it suggests a more straightforward relationship with the failure mechanism. Understanding this aspect helps in effective vibration analysis and diagnosis, allowing for timely maintenance decisions based on the observed vibration patterns.