Motor Starting Times
Motor Starting Times
(OP)
Dear all,
Is there any typical formula to estimate the starting times (No load and Full Load) of pump, fan and conveyor motors. The Data I have at the moment are the motor rating, voltage, and estimated BHP. I am going to use this data on my load flow and static motor starting studies on a conceptual project I am working on.
I hope motor and plant experts can give me a hand or guidance.
Is there any typical formula to estimate the starting times (No load and Full Load) of pump, fan and conveyor motors. The Data I have at the moment are the motor rating, voltage, and estimated BHP. I am going to use this data on my load flow and static motor starting studies on a conceptual project I am working on.
I hope motor and plant experts can give me a hand or guidance.
GO PLACIDLY, AMIDST THE NOISE AND HASTE-Desiderata





RE: Motor Starting Times
GO PLACIDLY, AMIDST THE NOISE AND HASTE-Desiderata
RE: Motor Starting Times
Time for a motor to reach operating speed:
Seconds = WK2 x Speed Change (RPM)
308 x AAT
AAT (Average Accelerating Torque) = {(FLT + BDT)/2} + BDT + LRT
3
Where;
BDT = Breakdown Torque
LRT = Locked Rotor Torque
FLT = Full Load Torque
WK2 = Total inertia (motor rotor plus load inertia)
RE: Motor Starting Times
Normally the load inertia of centrifugal pumps is quite under the figures allowed by such standard. However conveyors could have high moment of inertia. Make a research for your application figures.
RE: Motor Starting Times
GO PLACIDLY, AMIDST THE NOISE AND HASTE-Desiderata
RE: Motor Starting Times
RE: Motor Starting Times
Taccelerating(w)=Telec(w)-Tmech(w) = J dw/dt
w = (1/J) Integral[Taccelerating(w)] dt
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RE: Motor Starting Times
Another more direct approach:
Taccel(w) = J dw/dt
dt = (J/Taccel(w))dw
T = Integral [J/Taccel(w)] dw from w=0 to wfinal
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
RE: Motor Starting Times
=====================================
Eng-tips forums: The best place on the web for engineering discussions.