Motor size

[Lan123]

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%.

 

[Artisi]

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.)

 

[Lan123]

Pump curve is attached. The flow is in gpm.

 

[MechEngNCPE]

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

 

[TenPenny]

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.

 

[bimr]

Use the online calculator at engineering tool box to determine the approximate HP.

http://www.engineeringtoolbox.com/pumps-power-d_505.html

It calculates to 11.6 BHP

 

[TenPenny]

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...

 

[Artisi]

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.)

 

[Lan123]

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.