Pump Motor of Inertia-Calculation
Pump Motor of Inertia-Calculation
(OP)
How does one calculate the moment of inertia for a pump, motor and the rotating fluid? OK I know you can get it from themanufacturer but on some occassions the fluid rotational mass, coupling etc is missing. Yes I guess the motor manufacturers are prety good at having the information.
Is it done on a test bed?
Is it done on a test bed?





RE: Pump Motor of Inertia-Calculation
RE: Pump Motor of Inertia-Calculation
I need the data for transient analysis purposes.
RE: Pump Motor of Inertia-Calculation
In theory you could calculate rotating inertias from observing the way the rotating elements accelerate under a known torque, but that sounds like a lot of work.
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RE: Pump Motor of Inertia-Calculation
How much engineering judgement goes into the procedure? Once the MOI is known for one size of pump in a family of pumps can one use a correlation to determine the rest?
MOI for cylinders I can look up in the texts, thanks anyway.
RE: Pump Motor of Inertia-Calculation
The software i used to work with needs MoI as an input necessary for transients calculation.
I am not an expert in this field but I have done more than a few calculations, and I think that the error will be negligible in all respects if you add cca 15% to the known motor MoI and use this MoI as an input to your simulation.
If you want to stay on a safe side, use known motor MoI and neglect the pump+coupling MoI.
On the other side, the MoI is relevant only until non-return valve closes. Don't forget to take that into account.
RE: Pump Motor of Inertia-Calculation
good luck!
-pmover
RE: Pump Motor of Inertia-Calculation
I specialise in surge analysis. The software i use allows the input of momoent of inertia. I also have models to estimate the MOI based upon Streeter & Wylie anbd their industry referenced database.
I really want to know how the pump manufacturer goes about it. Is it by testing or some theoretical calculation based upon the pump series and then authenticated on the test bed?
Any pump designers out there?
RE: Pump Motor of Inertia-Calculation
Remember...
"If you don't use your head,
your going to have to use your feet."
RE: Pump Motor of Inertia-Calculation
what is the name of the software you use?
in my ex-company, we used an old custom-made program with primitive interface, but it was giving very good results.
We also wanted to have a comercial software, as to double-check the results. What commercial software (with cost less than 5-6000$) would you recommend?
RE: Pump Motor of Inertia-Calculation
RE: Pump Motor of Inertia-Calculation
I am not sure of the US price as I am in Australia and only pay for upgrades these days. The price is on the website. You can also download demos.
Its a great program because its drag and drop functionality to build models quickly. Flexible databases allow you to build up pump profiles etc. They also have all the standard mitigation devices as junctions that you can configure.