Multiple-shaft machine
Identify and mark the 1X and harmonics of the pump on the spectra. The pump RPM can be found from the VTAG, or can be calculated from the motor speed and gear ratio as follows: If the motor is turning 1780 and the gear ratio is 2.3 to 1, then the pump speed is:
Identify and mark the pump vane pass frequency and harmonics, if any, on the spectra. The vane pass is the number of vanes times the pump RPM.
Search the spectra for non-synchronous components that could be bearing tones, or consult the VTAG for bearing tone frequencies, and mark them on the spectra.
After performing all these tasks, you are ready for the work described in next chapter on Machine Diagnostics.
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