Choosing an electric motor power for a pump.
Choosing an electric motor power for a pump.
(OP)
I have selected a pump according to flowrate and head. How do I get to know which motor power will be suitable to drive that pump?
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
Choosing an electric motor power for a pump.
|
RE: Choosing an electric motor power for a pump.
Flowrate * density * head and divide by the pump's efficiency at that flowrate. Add IMO, about 20 to 25% and you'll get close to sufficient power required. Pick a motor size from the standard sizes available.
Examine performance from start-up speed to maximum operating speed.
Determine if you need additional controls.
Lastly, find some engineer that has experience with pump applications to review your work. Internet answers or supervision don't count. This part is the most important aspect of this problem.
http://virtualpipeline.spaces.msn.com
RE: Choosing an electric motor power for a pump.
Water HP is given by, (gpm x 8.33 x SG x head(ft)/33000)
and Water kW is given by, (head(m) x flow(ltr/min)/6000)
BHP or BKW is calculated by dividing WHP or WKW with efficiency of the pump.
IHP or IKW is calculated by dividing BHP or BKW with efficiency of pump (couplings can be treated as 100% efficient)
Then motor can be selected considering some FOS. (say, 10 to 20%)
RE: Choosing an electric motor power for a pump.
Q*H*SG/102*E = kW
Q = (litres/sec)
H= (metres)
E= pump efficiency - as a decimal - at the point of consideration
S.G. = 1 if water
102 = constant to assemble all the other factors and conversions.
This gives you the power requirement at the "duty point", from here you need to consider a number of other factors which comes down to experience of pumping systems;
can the pump run-out further on its performance curve at any time during operation?
is the pump duty constant or variable?
is S.G. constant?
what are the start-up charactristics of the system?
is voltage to the motor constant?
factor in ambient temperature and altitude and dusty operating conditions if applicable.
What is important is to select a motor that will not be forced to operate in an overload condition at any point within its application / hydraulic range - if this is not possible other measures must be introduced to protect the motor.
In most cases, the motor size is dictated by what is available from the standard range of motors up to around 200kW over this size you can usually specify the rating that you need.
Trust this helps.
Naresuan University
Phitsanulok
Thailand
RE: Choosing an electric motor power for a pump.
Going the Big Inch!
http://virtualpipeline.spaces.msn.com
RE: Choosing an electric motor power for a pump.
RE: Choosing an electric motor power for a pump.
http://ww
Going the Big Inch!
http://virtualpipeline.spaces.msn.com
RE: Choosing an electric motor power for a pump.
A great link and a good explanation.
Naresuan University
Phitsanulok
Thailand
RE: Choosing an electric motor power for a pump.
Geoffrey D Stone FIMechE C.Eng;FIEust CP Eng
www.waterhammer.bigblog.com.au