| 摘要 |
The invention concerns a method of operating a protection device (8) arranged between an electrical three-phase power source (4) and at least two electric motors (6), the method comprising the steps of:
-for each phase of the power source (4), acquiring over time a corresponding phase current flowing from the power source (4) to the at least two electric motors;
- based on predetermined motor parameters, rank of each motor in the startup sequence and the acquired phase currents, detecting in which current stage each electric motor (6) is, among an initial stage, an intermediate stage successive to the initial stage and a steady-state stage successive to the intermediate stage;
- calculating an active threshold value depending on the detected stage of each electric motor (6), the active threshold value during the intermediate stage following a predetermined decreasing function over time. |
