The utility model relates to an equipment monitoring alarm device technical field, test the speed DC radiator fan's for the instrument of pulse signal output radiator fan trouble alarm device of specific long -term continuous operation of specially adapted and having of saying so, its characterized in that is equipped with pulse signal treatment circuit, comparison circuit, warning circuit, voltage stabilizing circuit, and wherein the output of pulse signal treatment circuit is connected with comparison circuit, and comparison circuit's output is connected with warning circuit, and comparison circuit is connected with voltage stabilizing circuit, compared with the prior art, the utility model, has the advantage that rational in infrastructure, reliable operation etc. Is showing.