Abstract: A detection system for detecting fan's connection and disconnection states includes a detection module connected to a fan and a host. The fan has four external connection terminals for connecting to the detection module. Two of the four external connection terminals are a rotation speed control terminal, via which a detection signal and a rotation speed control signal are transmitted from the detection module to the fan, and a rotation speed feedback terminal, via which a fed back detection signal and a fan rotation speed signal are transmitted from the fan to the detection module. The host determines whether the fan is connected to or disconnected from the detection module according to whether or not a fed back detection signal is received by the detection module from the fan.

Abstract: A fan system includes a stator assembly and a monitoring and sensing module. The stator assembly is electrically connected to the monitoring and sensing module, and the latter includes at least one sensor unit, at least one monitoring unit and a signal processing unit. The sensor unit of the monitoring and sensing module senses an operating state of the fan system, and the signal processing unit processes the sensing results of the sensor unit and actively generates a warning in the event of an abnormal operating state of the fan system, so as to protect the fan system against an operation failure due to any abnormal operating state and thereby reduce the fan system's maintenance cost.