...2. measure the motor vibration, the result is as attached,...
was the vibration data taken with the motor connected to the compressor? if so, at what loading/RLA?
the best open rotor test using vibration equipment is by measuring the dB of the current...see attached.
the main peak in the middle is the line frequency (60 Hz) and the large peak to the left is the rotor turning speed (57.469 Hz). the difference is about 32 dB. anything less than 45 dB indicates the beginning of a problem...<30 dB means that the motor is going to try to walk out of the door!
It's tube brushing season...93% done (38.73 miles of tubing)...only 1,112 tubes to go!