Time Taken to stop a pump?

[Ahmedaoso]

I want to ask if there is an ESD interlock action to stop a pump due to any circumstances like very low level switch in a separator how much does it takes to stop the pump after the signal reached??

 

[BigInch]

That depends mostly on the type and size (rotating inertia) of the pump, the pump's driver and to a somewhat lesser extent the momentum of the fluid about to through. In general, electric drives can stop rather quickly, where internal combustion engine drivers may have slower shutdown procedures.

What type of pump, size and driver type do you have?

Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso

 

[Ahmedaoso]

Thank you for your quick reply
The pump is centrifugal. it delivers about 300 m3/hr of contaminated water- electric motor driven.
I want to know only is that occur instantly or it takes seconds or it takes minutes?

 

[JJPellin]

Seconds.

Johnny Pellin

 

[Ahmedaoso]

May I ask u to give me a range??

 

[1gibson]

You can kill the electric motor immediately, and depending on the pump configuration, "spin-down" will take typically 10-30 seconds before it actually comes to a stop.

 

[SNORGY]

300 m^3/hr is about 1321 USGPM; it "feels" like 1gibson's range of 10-30 seconds for spindown is reasonable.

Regards,

SNORGY.

 

[cvg]

depends quite a bit on the rotational speed of the pump

 

[stanier]

You need to do a transient analysis to determine the time taken. It all depends on the rotational speed of the assembly, system hydraulics, friction in the pump and moment of inertia of the pump/motor/coupling/entrained fluid.

Depending upon the system the pump could be driven by the fluid in turbine mode.

You cannot guess it.

If it is critical fit a VFD with dynamic braking. Make sure you have safety devices for that time you lose power and the pump trips but the VFD isnt working.

SOme major installations have flywheel generators in place so that on loss of power they keep power on critical equipment to allow controlled stop. An electro mechanical UPS if you like.

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