... patent, tube protect and downdraft suction type pumps with high power, big flow, high-lift are designedespecially for rescuing drainage under ... (1). Voltage 380V, allowable variation ±5%, frequency 50HZ, three-phrase power source with an allowable variationof ±1%(2). The inner cavity of ... or less.(10). Water which is yield from the water source should meet the necessary of the pump's continue work ...