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Motor size

Motor size

Motor size

(OP)
How can I determine the approximate motor size for a sewage pump that has an operating point of 6600 gpm @ 6 ft. The pump speed is 330 rpm. The pump manufacture's bhp curve shows a maximum value of 170 at startup, and, 130 at the operating point. The pump efficiency at the duty point is 86%.

RE: Motor size

Suggest you post the pump curve, as this flow and head is nowhere near 130hp - or am I missing something?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)  

RE: Motor size

Ask the vendor.  They should publish the hp lines on the curve.

RE: Motor size

If the pump manufacturer's curve shows 170hp at startup, one would think that you'd want more than 170 hp motor.

Unless you don't plan to start the pump.

RE: Motor size

I would say that you can't see the decimal in the hp scale; I'm willing to bet that it goes from 0.0 to 18.0 hp, not 180...

RE: Motor size

This is a typical mixed / axial flow pump curve, as you sure it's suitable as a sewage pump.

The power you suggested is out by a factor of 10.

The starting power is not (170hp) 17hp - this is the power if operating at maximum head and zero flow not a starting condition.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)  

RE: Motor size

(OP)
Thanks folks for all the feedbacks. I have requested the vendor to provide me the motor information. I will let you know when I heard back from him.

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