Drive system comprising an arrangement for identifying grid faults, characterised in that the drive system has - a converter having an inverter and a rectifier , which can be powered from an AC voltage supply grid, in particular by means of a grid filter , - an electric motor (M), - an evaluation unit comprising a counter, which is incremented in accordance with a clock signal, and a memory, in particular a circular buffer , - comparators and - a logical gating means , wherein the DC voltage-side terminal of the inverter of the converter can be powered from the DC voltage-side terminal of the rectifier , wherein the electric motor can be fed by the inverter, wherein each phase voltage of the AC voltage supply grid is assigned one of the comparators , wherein the output signals of the comparators are supplied to the logical gating means , the output signal of which is supplied to the evaluation unit in a galvanically isolated manner, wherein each comparator generates an output signal, which has synchronous pulses with respect to the zero crossings of each phase voltage of the AC voltage supply grid and is supplied to the logical gating means , wherein the drive system is configured such that the output signal of the logical gating means is supplied to the resetting input of the counter, wherein the evaluation unit is configured such that the counter status present each time the counter is reset is evaluated in the memory, in particular the circular buffer , of the evaluation unit , which actuates a display for displaying a grid fault, wherein the comparators are implemented as inverting or non-inverting Schmitt triggers. the drive system has - a converter having an inverter and a rectifier , which can be powered from an AC voltage supply grid, in particular by means of a grid filter , - an electric motor (M), - an evaluation unit comprising a counter, which is incremented in accordance with a clock signal, and a memory, in particular a circular buffer , - comparators and - a logical gating means , - a converter having an inverter and a rectifier , which can be powered from an AC voltage supply grid, in particular by means of a grid filter , - an electric motor (M), - an evaluation unit comprising a counter, which is incremented in accordance with a clock signal, and a memory, in particular a circular buffer , - comparators and - a logical gating means , wherein the DC voltage-side terminal of the inverter of the converter can be powered from the DC voltage-side terminal of the rectifier , wherein the electric motor can be fed by the inverter, wherein each phase voltage of the AC voltage supply grid is assigned one of the comparators , wherein the output signals of the comparators are supplied to the logical gating means , the output signal of which is supplied to the evaluation unit in a galvanically isolated manner, wherein each comparator generates an output signal, which has synchronous pulses with respect to the zero crossings of each phase voltage of the AC voltage supply grid and is supplied to the logical gating means , wherein the drive system is configured such that the output signal of the logical gating means is supplied to the resetting input of the counter, wherein the evaluation unit is configured such that the counter status present each time the counter is reset is evaluated in the memory, in particular the circular buffer , of the evaluation unit , which actuates a display for displaying a grid fault, wherein the comparators are implemented as inverting or non-inverting Schmitt triggers. <EOS>