| 摘要 |
PURPOSE:To enable the fault of a fan to be detected by detecting rotation pulse signal from fan bodies, to generate the output of fan selection or non- selection signal, and by detecting the presence or absence of the pulse of a signal line in the state of non-selection signal output, to check the working of a selecting means. CONSTITUTION:By a selecting means in fan bodies U1-Ui, selection signal fed via a selection line L1 is received, and specified fans 11-22 are selected, and rotation pulse from the selected fans 11-22 is fed back to a rotational frequency detecting means 31. In case that the working of the selecting means is abnormal, the fans 11-22 are not to be correctly selected. By a selection signal generating means 32, the output of non-selection signal is generated besides generating the output of the selection signal, and by a check means 33, the presence or absence of the then signal line L2 pulse is checked, and then, the abnormal working of the selecting means is detected. As a result, the fault of the fans 11-22 can be detected at the same time as the high reliability is kept. |
