Test and analysis methods for resolving fan/motor vibration problems in air-conditioning units

This thesis deals with part of ASHRAE Research Project No. 685-RP: Test and Analysis Methods for Resolving Fan/Motor Vibration Problems in Air-Conditioning Units. The objective is to develop the basic analytical models and experimental procedures that can be used to find the vibration modes associated with fan impeller, motor and motor mount in air-conditioning units that are excited by fan impeller unbalance, taking into account the gyroscopic effect of the rotating fan impeller; Two air-conditioning units were investigated in the project. They were designated as test units #1 and #2. For the test unit #1 and test unit #2, the vibration problems associated with fan impeller, motor and motor mount system that are excited by fan impeller unbalance taking into account the gyroscopic effect of the rotating fan impeller were investigated; Both non-rotating and rotating tests were conducted in this work. The non-rotating tests were used to measure the vibration modes associated with fan impeller, motor and motor mount system and to identify the parameters used in the analytical models. The rotating tests were used to measure the vibration mode shifting due to the gyroscopic effect of the rotating fan impeller and to locate the resonance speeds corresponding to both the forward and backward rocking modes. (Abstract shortened by UMI.)