The geometrical limitations of microphone arrays as well as the unavailability of multiple channel data ac- quisition systems or their incurred costs fundamentally challenge the sound source identification in acoustic imaging. This can be solved by sequentially scanning the object of study with a moving array with or without fixed references and requires the sound field to be stationary. In rotating machines, the generated vibroacoustic phenomena during a run-up or coast-down are non-stationary, and conventional resynchronization techniques cannot be directly implemented. To solve this problem, this study proposes a novel approach called Angu- lar Speed Resynchronization (ASR). The orders from several sequential measurements are first extracted us- ing time domain order tracking techniques, then synchronized into a single data set over which order based beamforming (OBBF) is performed. OBBF is an acoustic imaging technique that aids in the identification of non-stationary tonal sources. Given that the radiated sound field is determined for a given angular speed, the complex envelopes in the data set are realigned with respect to speed as if they were obtained from the same measurement with a full array. The proposed method is evaluated using an experimental data set collected from an induction motor. The approach demonstrates the capability of OBBF to accommodate with non-synchronous measurements during variable operating speed.