In the examination of motor protection, it is essential to take into account that, during the initial phase, the machine draws a current approximately six times its rated value for a variable duration. This duration is dependent on the specific characteristics of the driven machine. In the case of a network short-circuit, the motor exhibits behavior akin to that of a generator in the initial moments. It supplies the fault with a current theoretically equivalent to the starting current. Both the startup conditions and the motor’s contribution to the short-circuit are significant operational scenarios. Therefore, the design of protection measures is crucial to prevent false trips under these circumstances.
Motor faults or abnormal operating conditions can be categorized and identified.