The Need to Consider the Skin Effect in the Study of Direct Start-up of the Squirrel-cage Induction Motor

Exploitation of squirrel-cage induction motors (SCIMs) is inevitably accompanied by the appearance of the transient processes that critically impact the condition and operation of electrical machines. In the study of transients in induction motors must consider that during the start-up, the rotor parameters (resistance and inductance) are changing due to the skin effect. The current paper is dedicated to the research of the direct start-up of the SCIM with due account for of the current’s displacement in the rotor slots. The starting and nominal torque’s values of different power SCIMs were calculated. The conclusion about the need to consider the skin effect in the study of direct start-up of SCIMs is given. Calculation and comparison are also given for the dynamic characteristics of SCIMs with constant and variable parameters of the rotor