| 摘要 |
PURPOSE:To prevent a pump from being damaged in the time of its abnormality, by comparing an operation signal through a detection rotary speed with the reference signal and stopping an electric motor when a condition with the operation signal out of the reference signal continues for the predetermined time or more. CONSTITUTION:A comparator 4 inputs an output from a rotary speed detector 3 simultaneously a reference signal 5. An output of the comparator 4 is input to a timer 6, and its output is input to a stop signal part 7 of an electric motor 2. Comparing the detection speed signal with the reference signal 5, the output of the comparator 4 is given to a timer 6, and if the fixed time elapses, the timer 6, forming its output to be a signal of stopping the electric motor 2 in its stop signal part 7, stops the electric motor 2. Accordingly, a pump can be prevented from its abnormal operation.
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