External Gear Pump Eccentricity and Backlash
New external gear pump exhibits high vibration levels, particularly in the horizontal direction, due to gear meshing frequency and eccentricity/backlash issues.
A new installed external gear pump suffers from high vibration levels especially in the horizontal direction reaches 13 mm/sec rms, a quick vibration survey was conducted to figure out what is the main reason behind the high amplitudes, we found a dominant peak of 272.2 Hz which equals 11X and its 2nd & 3rd harmonic components with sidebands, as expected the number of teeth each gear has is 11 teeth so it was confirmed that 272.2 Hz is the gear meshing frequency, manual rotation of pump shaft showed strange meshing behavior and the spectra analysis confirmed that there is a eccentricity/backlash, , that was unusual as the pump is new, attached some images contains acceleration TWF and spectrum.
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