Protection device for protecting electrical machine i.e. engine, against current overloading, has utilization device for generating control signal by utilizing comparison result in machine model computation

摘要

The device (1) has a current evaluation unit (2) for determining phase unbalances on basis of measured phase current values of an electrical machine (M), where the phase unbalances are defined as a relationship from minimum to maximum phase current values of a phase current measurement. A comparator (3) compares the determined phase unbalances with a limit value. A utilization device (4) generates a control signal (5) e.g. switching off signal and warning signal, by utilizing the comparison result in a machine model computation under consideration of the determined phase unbalances. An independent claim is also included for a method for protecting an electrical machine against current overloading.