Starting a large centrifugal pump

[Freeportpower]

Gentlemen,

I am involved with the design of a water pumping station equipped with 3 centrifugal pumps fitted with 450kW (415V) each capable of delivering 112 l/s and the static head is 277 metres.
The contractor has proposed star delta starters but I understand that on delta transition the inrush can be worse than DOL starter.
I am concerned that there will be excessive torque during start up with consequential electrical and/or mechanical damage to the pump set.
Your comments would be appreciated,

FPP

 

[ScottyUK]

Centrifugal pumps should do fine on a soft start. If you must use a Y-D starter then make sure it is a closed transition type. Open transition types have significantly worse transients during switching.

You will get a lot of useful response from forum237. If you re-post please leave a note here with a link to the new thread.


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If we learn from our mistakes I'm getting a great education!

 

[dcasto]

to add on to Scotty's. the centrifugal pump require very little torque at start up because of the fan laws. as the rpm goes up, the power require goes up at rpm^3 so at say 1/2 speed, the pump uses 1/8 the power.

 

[BigInch]

And they have pleanty of torque available at low speed.

Where you might need a lot of torque quickly is when it comes to opening a check valve between the pump and that 277m of head downstream. In that case, you won't need much at all until you manage to open the check.

"If everything seems under control, you're just not moving fast enough."
- Mario Andretti- When asked about transient hydraulics

http://virtualpipeline.spaces.msn.com

 

[rshayesteh]

Maybe one other point to consider is the position of the isolation valve when starting your pump. Actually it depends on the impeller type and on BHP curve of the pump. If the BHP curve is increasing after shutoff point, you should start the pump with closed valve to demand less electric power, and open the valve gradually in some seconds.