From 7f60ea012dd2524dae921a2a35adbf7ef21f2bb6 Mon Sep 17 00:00:00 2001 From: prashantsinalkar Date: Tue, 10 Oct 2017 12:27:19 +0530 Subject: initial commit / add all books --- 3731/CH6/EX6.6/Ex6_6.sce | 91 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 3731/CH6/EX6.6/Ex6_6.sce (limited to '3731/CH6/EX6.6/Ex6_6.sce') diff --git a/3731/CH6/EX6.6/Ex6_6.sce b/3731/CH6/EX6.6/Ex6_6.sce new file mode 100644 index 000000000..9e1487acd --- /dev/null +++ b/3731/CH6/EX6.6/Ex6_6.sce @@ -0,0 +1,91 @@ + +//Chapter 6:Induction Motor Drives +//Example 6 +clc; + +//Variable Initialization + +//Ratings of the star connected Induction motor which operates under dynamic braking +f=50 // frequency in HZ +P=6 // number of poles + +//Parameters referred to the stator +Xr_=3.01 // rotor winding reactance in ohm +Xs=Xr_ // stator winding reactance in ohm +Rr_=4.575 // resistance of the rotor windings in ohm +Rs=1.9 // resistance of the stator windings in ohm +J=0.1 // moment of inertia of the motor load system in kg-m2 +Id=12 // given DC current + +N=1500 //given asynchronous speed +//magnetization chacrateristic at the given asynchronous speed +Im=[0.13,0.37,0.6,0.9,1.2,1.7,2.24,2.9,3.9,4.9,6,8,9,9.5] //magnetization current +E=[12.8,32,53.8,80,106,142,173,200,227,246,260,280,288,292] //back emf + +//Solution +Ns=120*f/P //synchronous speed in rpm +torque=[] +speed=[] +temp=[] +Is=sqrt(2/3)*Id //value of stator current for two lead connection +Wms=2*%pi*N/60 +for i=2:14 +x=(Is**2-Im(i)**2)/(1+2*Xr_*Im(i)/E(i)) //x=Ir_**2 +Ir_=sqrt(x) //required rotor current +y=(E(i)/Ir_)**2-Xr_**2 +S=Rr_/sqrt(y) //required slip +N=S*Ns //required speed +T=(3/Wms)*(Ir_)**2*Rr_/S //required torque +speed($+1)=N +torque($+1)=T +temp($+1)=T +end +mprintf("Hence the magnetization curve is") +disp(speed,"Speed:in rpm") +for i=1:13 +torque(i)=-1*torque(i) +end +disp(torque,"Braking torque :in N-m") + +//Results + +//Plot of of torque vs speed +subplot(2,1,1) +plot(torque,speed) +xlabel('Torque, N-m') +ylabel('Speed, rpm') +title('Torque vs Speed') +xgrid(2) + +//Plot of Wm vs J/T +inertia_over_torque=[] +for i=3:13 +J_T=1000*J/temp(i) +inertia_over_torque($+1)=J_T +end +disp(inertia_over_torque,"J/t :") + +Wm=[1,4,8,12,16,20,25,55,95,125,160] +//the values of Wm are taken for the angular frequency with maximum value of Wms=50*pi rad/s +subplot(2,1,2) +plot(Wm,inertia_over_torque) +xlabel('$Angular speed \omega_m$') +ylabel(' J/T,1*10e-2') +title('$J/T vs \omega_m$') +xgrid(2) +x=[6.5,6.5] +y=[2,4.5] +plot(x,y,'blue') +str=["${A}$"] +str1=["${B}$"] +str2=["${C}$"] +str3=["${D}$"] +str4=["${E}$"] +xstring(6,2,str) +xstring(6,4.5,str1) +xstring(80,3.4,str2) +xstring(156,8.3,str3) +xstring(156,2,str4) + +mprintf("Hence from the plot the area ABCDEA between the curve and the speed axis for speed change ") +mprintf("for synchronous to 0.02 times synchrnous speed is the stopping time which is equal to: 9.36 sec") -- cgit