【Daily Question: Pump Equipment】Fill-in-the-blank question, May 29, 2019
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bk14.jpg Rules for answering questions and management: 1. If all answers to a question are incorrect or only one answer is correct, a reward of 2 Wealth points will be given for active participation； 2. For the answer section (answering any two correctly), a reward of 5 wealth points will be given ； A reward of 8 wealth for all correct answers ； 3. Rewards for answers are available once per person only ； 4. Each reply allows for one management rating only ； 5. The answer and explanation will be visible after responding ； 6. The reply reward is valid for 48 hours. The student has won awards again; come by here every day. The rated flow rate of this centrifugal pump is 75 m3/h, the head at this rated flow rate is 146 m, and the efficiency at that flow rate is 62.5%. The rated rotational speed is 2950 rpm, and the specific gravity of the fluid is 1.15. The maximum flow rate under operating conditions is 88 m3/h, the head at this maximum flow rate is 137 m, and the efficiency at that flow rate is 65%. What is the shaft power at the rated flow rate in kW? And what should be the power of the motor required to drive this pump in kW? Answer: 75*146*1.15/（3.6*102*0.625）=54.87kW ； 88*137*1.15/（3.6*102*0.65）=58.1; therefore 75kW is chosen
54.87KW 75KW
54.87KW??75KW
This post was last edited by bulusli on 2019-5-29 08:36 to 54.9, 63.8. The author’s second calculation is incorrect; how can the motor power be determined simply based on the shaft power? The motor power is also related to the transmission efficiency and the motor’s margin sacrifice factor.
The selection of motors for this section is carried out in accordance with API610, GB3215, and GB5656, taking into account the margin for shaft power
The shaft power at the rated flow rate is (55) kW, and the motor required for this pump should have a power of (75) kW.
21.3KW,30KW
54.87kW, 75kW