How do you determine HP given a flow rate and discharge?

[Cee555]

See the subject of this here post.

Also can someone tell me what turn down gear ratio means?
ie 10-1 what does that mean?

 

[TD2K]

Hp required by a pump?

Hp = dP * Q / (1714 * e)

dP is the differential pressure across the pump in psi
Q is the flow rate in gpm
e is the pump efficiency.

 

[25362]

Another generally used formula is:

HP = QH(sp.gr.)[÷](3960 e)​

Q, gpm
H, ft
e, overall efficiency
sp.gr. specific gravity of the liquid being pumped

Gear ratios can be used to step up or down the speed of the follower gear in respect of the driven gear.

 

[25362]

H is the differential (or developed) head, mostly used with centrifugal pumps.

 

[DesignerMike]

In a very GENERAL description, 10:1 turndown means that a 60 hz motor can be apperated at 1/10 speed (6hz) without damage...it usually means you will get constant torque to that speed. 6:1 would equate to 1/6 speed (10hz)

This does NOT mean that the motor can't be run slower than that (escpecially if the load is much less than the motor is capable of).

Beware that a 2hp 60hz motor will NOT generate 2hp when operated at 10hz! so design accordingly.