Abstract
This paper describes the experimental results on the transient vibration of a structure excited by unbalanced rotors. When some rotors run on a base plate, which is free to vibrate horizontally, two modes of synchronization, i.e., in-phase synchronization and out-of-phase synchronization are observed under some operational conditions. In the case of in-phase synchronization, some rotors which rotates higher than critical speed are entrained into critical speed and the base plate vibrates violently. The quasisynchronization are also observed.
