i have to use a 3 phase induction motor in a raw water pump house. the flow is 1950m3/hr and rating is 160 kw. i have a offer to use either a 1450 rpm, 4 pole 3 phase induction motor and 980 rpm 6 pole 3 phase induction motor. which motor i have to use to drive a centrifugal pump of 22 mWC head?.

 

Dear Narendra,

Check the Characteristic Charts Flow vs Head of Your Mechanical Pump with reference to 1450 rpm as well as 980 rpm Speed. If your Pump efficiency is good for both rpm than check which Electrical Motor is Cheaper for you with respect to purchase & maintenance.

In simple terms Power (kW) = Flow x Head x SG / (367 x Effy)

Use 15% more KW / Hp rated electric motor for your required rpm.