| 摘要 |
PURPOSE:To decrease the width of a fluctuation in a pressure, by a method wherein, when one of 2 pumps fails in operation, the other pump is automati cally started, and following action is controlled by a pressure switch for alternat ing operation. CONSTITUTION:Two pumps P1 and P2 are controlled by a pump motion control device (c), and are alternately driven through making and breaking of a pressure switch Psw1 for alternating operation. Outputs from AND 16 and 17 are compared with outputs from trouble detectors 12 and 11 by an exclusive theoretical sum circuits 24 and 25, and control is effected so that, when a No. 1 pump P1 fails in operation, a No. 2 pump P2 is started to drive. Thereafter, one-pump automatic operation is effected by the pressure switch Psw1 for alternating operation and the No. 2 pump P2. This prevents wide fluctuation of the water pressure of delivery water.
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