Synchronous Power Transfer to Induction Motors Operating with Variable Frequency Drives Case 2: Supervised Fast Transfer

The supervised synchronous transfer of an induction motor between a variable frequency drive (VFD) output and the main supply represents a precise procedure aiming to eliminate the drawbacks represented by hard transients. The paper analyses the process of fast synchronous transfer and highlights the advantages over the unsupervised fixed time synchronization. Preliminary tests lead to the implementation of a functional control systems which proven to be useful in confirming the overall superiority of the fast transfer method. A Programmable Logic Controller (PLC) assures the supervision of the fast transfer process. Specific captured waveforms of the system operating at specific times reveal as safe transfer of the induction motor between the two sources, accompanied by a smooth and short transient regime.