Method and device for monitoring an electric network in a rail vehicle and rail vehicle

A device for monitoring an electric network in a rail vehicle,

• wherein the device comprises:
• at least one evaluation unit,
• at least one determination unit, and
• at least one interruption unit,
• wherein at least one phase line of the electric network is interruptible by the at least one interruption unit,
• wherein a potential difference between a machine-side part of the at least one phase line and a reference potential is determinable by the determination unit,
• wherein a potential-difference-dependent variable is determinable by the determination unit or the evaluation unit,
• wherein a speed of a permanent magnet machine of the electric network is determinable by the determination unit and, as a function of the speed, a speed-dependent reference variable is determinable by the determination unit or the evaluation unit,
• wherein a deviation of the potential-difference-dependent variable from the speed-dependent reference variable is determinable by the evaluation unit, and
• wherein a network fault is detectable by the evaluation unit if the deviation of the potential-difference-dependent variable from the speed-dependent reference variable is greater than a predetermined threshold value.