Internal gear Positive displacement Pump(Motor BKW too high because of Ext. Relief valve set press.) 1

[shashankTurbomachine]

REBOILER CIRCULATION PUMP
---------------------------------
CAPACITY: 95GPM
DIFF PRESS.: 17.92 PSI
DISCH. PRESSURE: 78.8 PSIG
VISCOCITY: 124.6
VAP PRESS.: 73.86 PSIA
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BIDDER OFFERED MOTOR OF 15HP BASED ON EXTERNAL RELIEF VALVE SET PRESSURE OF 145 PSIG.
RATED POWER WAS ONLY 1.98HP @ 165RPM.

ISN'T THE MOTOR RATING TOO HIGH???

 

[BigInch]

Maybe bidder doesn't make anything smaller than 15hp.

 

[shashankTurbomachine]

BIGINCH,
unfortunately THAT'S NOT CORRECT, I HAVE OTHER TAGS WITH MOTOR RATING AS LOW AS 5hp FOR SAME PROJECT BUT DIFF ITEM.

 

[TenPenny]

Long shot here, but when I wonder why someone offered something, I find asking that person why is helpful.

 

[BigInch]

shas, your caps button is locked on. Press it again and you can type normally.

 

[LittleInch]

Maybe a misunderstanding, but rated power is based on differential pressure of 17 psi with inlet of 60. You say relief valve is set at 145. This means pump might produce differential pressure of 85 psi at worst case compared.to rated of 17. Hence more power (x5 approx ) so at least 10hp. Suddenly 15 hp doesn't look so strange.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[georgeverghese]

Is this external 145psig RV the only RV on the discharge or is there another one set at a lower pressure?

 

[shashankTurbomachine]

one of the obvious reason for 15hp can be selection at 145psig.
But that's what i am amazed of.why??
Geor- No there is no any other RV except inbuilt internal RV with these viking pumps

 

[georgeverghese]

Well, that is the reason why this vendor has chosen this RV setting to be the basis for the motor hp - the motor has to be able to operate at pressures up to 145psig. Ask the vendor to lower this setting to some value suitable for your process.
Else install another normal capacity / backpressure recycle valve set at a lower pressure and add a margin to this pressure to ensure you have some margin on motor hp ( usually at least 10% between max operating hp and motor rated hp). For this case, select credible coincident upper or lower limit physical properties for this fluid that will demand more hp.