rated vs design power

[balaplus]

What is the difference between rated power and design power in a pump performance curve?

In general what is the difference between "rated" and "deisgn" ?

 

[quark]

Design power is power consumed by pump at the design flowrate and head. Rated power includes some margin to allow for increase in flowrate for overloading type pumps (which generally is about 20%)

 

[Ashereng]

Another definition I have heard is:
- Design Power: what you designed the pump to
- Rated Power: what the pump is capable of doing as measured

Raged power is the actual power your pump has. Design power was what the original calculations intended.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[MJCronin]

balaplus....

I am a little confused... I am assuming you are talking about centrifugal pumps here....

I have specified and purchased many types of pumps and have not come across these exact terms.

For centrifugal pumps, vendors offer the "calculated brake horsepower, at BEP". You then use this value to select an "electric motor horsepower", with the appropriate margin, as noted above.

If your process conditions change,(new BEP) you may be required to select a larger impeller (and reuse the same pump casing). This may require a new calculated BHP and larger electric motor.

Who commonly uses thes terms and where, in a published text or on the internet, are they used ??

-MJC

 

[25362]

When referring to pumps it appears to me that the concept of rating leans more towards actual operation, while design is associated with purpose.

 

[roker]

hello,

the rated power is the power required to operate the pump at rated flow and the head specified in the data sheet.

the design power, or max power, is the power required to operate the pump at the end of the chosen impeller.

regards,
roker