FAN CONTROLLER, REFRIGERATION CYCLE SYSTEM AND METHOD FOR ESTIMATING ROTATION SPEED OF FAN

摘要

[PROBLEMS] A fan controller capable of preventing demagnetization of the permanent magnet of a motor and breakdown of a switching element on the negative side of an inverter even if starting control is performed while the fan is rotating with natural wind, and a refrigeration cycle system and a method for estimating the rotation speed of the fan. [MEANS FOR SOLVING PROBLEMS] A control means (13) is provided that turns on switching elements for three phases forming the negative side arm of an inverter at the time of starting, and, when the current level detected by a current level detecting means (11) under on state exceeds a protection level set lower than a level being judged as short circuit of the arm, resets the switching elements for three phases to off state thus interrupting the starting operation.