Starting high inertia loads [induction motors]

Common methods used to start AC induction motors driving high inertia loads include across-the-line starting and reduced voltage starting by auto-transformer, wye-delta or resistor/reactor. Application of these methods is generally well documented and understood. However, with the increased use of electronic soft starters and variable frequency drives, applications can be markedly different. This paper reviews the aforementioned methods and explains the benefits and limitations of each. The effect of high inertia loads on both acceleration time and motor heating is examined. A case history of starting a centrifuge with an electronic soft starter is studied. Finally, a comparison of all of the methods is presented with recommendations on choosing the proper starter given.