Motor inertia information
Motor inertia information
(OP)
Please can you point me to information on how to estimate the inertia of a motor from its power, speed, etc, and to tables of data for the same?
Thanks
Thanks
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Motor inertia information
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Motor inertia informationMotor inertia information(OP)
Please can you point me to information on how to estimate the inertia of a motor from its power, speed, etc, and to tables of data for the same?
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RE: Motor inertia information
You will see from the physics books that inertia has no connection to power. You need the weight of the rotor.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Motor inertia information
Stuart
RE: Motor inertia information
thank you
RE: Motor inertia information
Usually the motor inertia is the dominant factor in the total inertia (except for magnetic drive pumps) hence my interest. I came across some algorithms some years ago to estimate inertia from the motor speed and power, but I found them inaccurate compared to the manufacturer data I collected then. I'm doing a new study, and Google etc didn't turn up anything earlier today so I thought I'd try asking the expert!
Stuart
RE: Motor inertia information
-The future's so bright I gotta wear shades!
RE: Motor inertia information
?m Mechanical Time Constant (seconds)
R Resistance (ohms)
KT Torque Constant (nM/A)
KE Back EMF Constant (v/r/s)
Inertia = (?m•KT•KE)/R Kg•m2
You can use other units of course, just be consistent.
RE: Motor inertia information
Inertia reflected to the shaft of the motor=
(Load RPM)squared/Motor RPM.
This info is on Reliance web site.
kind regards
Tim
RE: Motor inertia information
RE: Motor inertia information
If you've got a 326T frame motor, whether the motor is wound 30hp 6 pole or 40hp 4pole or 50hp 2 pole wouldn't change the rotor inertia much. Or would it?
RE: Motor inertia information
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RE: Motor inertia information
NEMA MG-1 2003
"14.46 ROTOR INERTIA FOR DYNAMIC BRAKING
The rotor inertia (Wk2) in lb-ft2 for the application of medium ac induction motors with dynamic braking
equipment may be estimated by the following formula:
WK^2=0.02*2^(poles/2)*hp^(1.35-0.05*poles/2)"
HP in HP. WK^2 in ft^2-pounds
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RE: Motor inertia information
JRaef.com
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RE: Motor inertia information
RE: Motor inertia information
When modeling pump inertia for a transient hydraulic analysis, you should also take into account the inertia of the pump and entrained liquid, not just the motor.
AFT Impulse software provides the following reference to estimate the inertia of the pump impeller, entrained fluid, and motor rotational inertia:
Wylie, E.B., V.L. Streeter & L. Suo, Fluid Transients in Systems, Prentice Hall, Englewood Hills, New Jersey, 1993
KLee777
RE: Motor inertia information
Thanks to all - very helpful.
Stuart