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//Chapter 4: Selection of Motor Power Rating
//Example 2
clc;
//Variable Initialization
N=200 //Speed in rpm
Tc=25000 //Constant Torque in N-m
J=10000 //Moment of inertia in Kg-m2
//Given Duty Cycles
t1=10 //For full speed and at constant torque
t2=1 //For no load at full speed
t3=5 //For speed reversal from N to -N
t4=1 //For no load at full speed
T5=20000 //Torque in N-m
t5=15 //At full speed and at a torque T1
t6=1 //For no operation at full speed
t7=5 //For speed reversal from -N to N
t8=1 //For no load operation
//Solution
Tr=J*(N-(-N))*2*%pi/60/5 //Reversal torque
x=Tc**2*t1+Tr**2*t3+T5**2*t5+Tr**2*t7
t=t1+t2+t3+t4+t5+t6+t7+t8 //Total Time
Trms=sqrt(x/t) //rms torque
Trated=Trms //Rated torque is equal to the rms torque
Pr=Trated*2*%pi*200/60 //Power rating
r=Tr/Trms //Ratio of reversal torque to the rms torque
Pr=Pr*1e-3
mprintf("Torque of motor is :%d N-m",Trms)
if r < 2 then
disp("Trms is rated equal to the Motor")
mprintf(" Trms=%d N-m\n",Trms)
end
mprintf(" Power rating :%.3f kW",Pr)
//The answer provided in the textbook is wrong
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