diff options
Diffstat (limited to '3574/CH5')
42 files changed, 929 insertions, 0 deletions
diff --git a/3574/CH5/EX5.1/EX5_1.png b/3574/CH5/EX5.1/EX5_1.png Binary files differnew file mode 100644 index 000000000..bf45569ec --- /dev/null +++ b/3574/CH5/EX5.1/EX5_1.png diff --git a/3574/CH5/EX5.1/EX5_1.sce b/3574/CH5/EX5.1/EX5_1.sce new file mode 100644 index 000000000..da00ee38f --- /dev/null +++ b/3574/CH5/EX5.1/EX5_1.sce @@ -0,0 +1,32 @@ +// Example 5.1
+// Computation of minimum value of (a) Locked rotor torque (b) Breakdown torque
+// (c) Pull up torque
+// Page No. 173
+
+clc;
+clear;
+close;
+
+// Given data
+f=60; // Frequency in Hz
+p=6; // Number of poles
+hp=10; // Horsepower
+n=1150; // Rated speed of machine
+ns=120*f/p;
+
+
+// (a) Locked rotor torque
+Trated=hp*5252/n; // Rated torque
+Tlockedrotor=2.25*Trated;
+
+// (b) Breakdown torque
+Tbreakdown=1.90*Trated;
+
+// (c) Pull up torque
+Tpullup=1.65*Trated;
+
+
+// Display result on command window
+printf("\n Locked rotor torque = %0.1f lb-ft ",Tlockedrotor);
+printf("\n Breakdown torque = %0.1f lb-ft ",Tbreakdown);
+printf("\n Pull up torque = %0.1f lb-ft",Tpullup);
diff --git a/3574/CH5/EX5.10/EX5_10.png b/3574/CH5/EX5.10/EX5_10.png Binary files differnew file mode 100644 index 000000000..21a28af0d --- /dev/null +++ b/3574/CH5/EX5.10/EX5_10.png diff --git a/3574/CH5/EX5.10/EX5_10.sce b/3574/CH5/EX5.10/EX5_10.sce new file mode 100644 index 000000000..9484505a5 --- /dev/null +++ b/3574/CH5/EX5.10/EX5_10.sce @@ -0,0 +1,34 @@ +// Example 5.10
+// Determine (a) Range of rotor speed (b) Required rheostat resistance
+// Page No. 198
+
+clc;
+clear;
+close;
+
+// Given data
+F=60; // Frequency of motor
+P=14; // Number of poles
+SL=0.395; // Low speed point
+SH=0.02; // High speed point
+Stdmax=0.74; // Value at which TD is maximum (from curve B)
+R1=0.403; // Motor resistance
+R2=0.317;
+X1=1.32; // Motor reactance
+X2=1.32;
+a=3.8; // Ratio of stator turns/phase to rotor turns/phase
+
+// (a) Range of rotor speed
+ns=120*F/P; // Speed
+nrl=ns*(1-SL); // Rotor low speed
+nrh=ns*(1-SH); // Rotor high speed
+
+// (b) Required rheostat resistance
+Rrhe=Stdmax*(sqrt(R1^2+(X1+X2)^2))-R2;
+Rehereq=Rrhe/a^2;
+
+// Display result on command window
+printf("\n Low range of rotor speed = %0.0f r/min",nrl);
+printf("\n High range of rotor speed = %0.0f r/min",nrh);
+printf("\n Required rheostat resistance = %0.3f Ohm/phase",Rehereq);
+
diff --git a/3574/CH5/EX5.11/EX5_11.png b/3574/CH5/EX5.11/EX5_11.png Binary files differnew file mode 100644 index 000000000..5691fd419 --- /dev/null +++ b/3574/CH5/EX5.11/EX5_11.png diff --git a/3574/CH5/EX5.11/EX5_11.sce b/3574/CH5/EX5.11/EX5_11.sce new file mode 100644 index 000000000..1cdd036a7 --- /dev/null +++ b/3574/CH5/EX5.11/EX5_11.sce @@ -0,0 +1,51 @@ +// Example 5.11
+// Determine (a) Rotor frequency (b) Slip at which TDmax occurs (c) Rotor speed
+// at 1/2 rated torque load (d) Required rheostat resistance (e) Rated torque
+// Page No. 201
+
+clc;
+clear;
+close;
+
+// Given data
+S=0.0159; // Slip
+Fbr=50; // Rated frequency
+R1=0.00536; // Motor resistance
+R2=0.00613;
+X1=0.0383; // Motor reactance
+X2=0.0383;
+Rrhe=0; // Initial rheostat resistance
+P=4; // Number of poles
+NR=1000; // Rated speed
+s1=0.0159; // Slip of rheostat
+a=2; // Stator to rotor turns ratio
+hp=400; // Motor horsepower
+
+// (a) Rotor frequency
+fr=S*Fbr;
+
+// (b) Slip at which TDmax occurs
+Stdmax=(R2+Rrhe)/(sqrt(R1^2+(X1+X2)^2));
+
+// (c) Rotor speed at 1/2 rated torque load
+s=S*(0.5)*(R2/R2); // Rotor speed at 1/2 rated torque
+ns=120*Fbr/P;
+nr=ns*(1-s); // Rotor speed
+
+// (d) Required rheostat resistance
+s2=(ns-NR)/ns;
+Rrhe2=((s2/s1)*(1/0.5)*(R2+Rrhe))-R2; // rheostat resistance
+Rrheostat=Rrhe2/a^2;
+
+// (e) Rated torque
+nr1=ns*(1-s1); // Rated speed
+T=hp*5252/nr1;
+
+
+
+// Display result on command window
+printf("\n Rotor frequency = %0.3f Hz",fr);
+printf("\n Slip at which TDmax occurs = %0.4f ",Stdmax);
+printf("\n Rotor speed at 1/2 rated torque = %0.0f r/min",nr);
+printf("\n Required rheostat resistance = %0.4f Ohm/phase",Rrheostat);
+printf("\n Rated torque = %0.0f lb-ft",T);
diff --git a/3574/CH5/EX5.12/EX5_12.png b/3574/CH5/EX5.12/EX5_12.png Binary files differnew file mode 100644 index 000000000..4d9b5b396 --- /dev/null +++ b/3574/CH5/EX5.12/EX5_12.png diff --git a/3574/CH5/EX5.12/EX5_12.sce b/3574/CH5/EX5.12/EX5_12.sce new file mode 100644 index 000000000..2899474fb --- /dev/null +++ b/3574/CH5/EX5.12/EX5_12.sce @@ -0,0 +1,20 @@ +// Example 5.12
+// Determine the percent increase or decrease in rotor circuit resistance
+// Page No. 202
+
+clc;
+clear;
+close;
+
+// Given data
+
+Stdmax1=0.45; // Maximum torque condition 1
+Stdmax2=0.80; // Maximum torque condition 2
+
+// Percent increase or decrease in rotor circuit resistance
+
+PerCh=1/(Stdmax1/Stdmax2);
+PerCh=PerCh-1;
+
+// Display result on command window
+printf("\n Percent change in rotor circuit resistance = %0.0f Percent increase",PerCh*100);
diff --git a/3574/CH5/EX5.13/EX5_13.png b/3574/CH5/EX5.13/EX5_13.png Binary files differnew file mode 100644 index 000000000..44344dab0 --- /dev/null +++ b/3574/CH5/EX5.13/EX5_13.png diff --git a/3574/CH5/EX5.13/EX5_13.sce b/3574/CH5/EX5.13/EX5_13.sce new file mode 100644 index 000000000..e2353e061 --- /dev/null +++ b/3574/CH5/EX5.13/EX5_13.sce @@ -0,0 +1,25 @@ +// Example 5.13
+// Determine the expected in-rush current
+// Page No. 208
+
+clc;
+clear;
+close;
+
+// Given data
+kva1=5.6; // KVA/hp lower limit from table 5.9
+hp=150; // Motor horsepower
+Vline=460; // Line voltage
+kva2=6.3; // KVA/hp upper limit from table 5.9
+
+// Expected in-rush current
+
+// Lower limit of expected range of in-rush current is
+Ilrss=(kva1*hp*1000)/(sqrt(3)*Vline);
+
+// Upper limit of expected range of in-rush current is
+Iulss=(kva2*hp*1000)/(sqrt(3)*Vline);
+
+// Display result on command window
+printf("\n Lower limit of expected range of in-rush current = %0.0f A",Ilrss);
+printf("\n Upper limit of expected range of in-rush current = %0.0f A",Iulss);
diff --git a/3574/CH5/EX5.14/EX5_14.png b/3574/CH5/EX5.14/EX5_14.png Binary files differnew file mode 100644 index 000000000..3e79d83d8 --- /dev/null +++ b/3574/CH5/EX5.14/EX5_14.png diff --git a/3574/CH5/EX5.14/EX5_14.sce b/3574/CH5/EX5.14/EX5_14.sce new file mode 100644 index 000000000..c5ecbe708 --- /dev/null +++ b/3574/CH5/EX5.14/EX5_14.sce @@ -0,0 +1,45 @@ +// Example 5.14
+// Determine (a) Percent voltage unbalance (b) Expected approximate temp. rise
+// if operating at rated load in a 40 deg ambient (c) Expected insulation life
+// (d) Required derating of motor to prevent shortening isulation life.
+// Page No. 211
+
+clc;
+clear;
+close;
+
+// Given data
+VL1=460; // Line voltage 1
+VL2=455; // Line voltage 2
+VL3=440; // Line voltage 3
+Trated=110; // Rated temp. (from table 5.8)
+hp=30; // Motor horsepower
+
+// (a) Percent voltage unbalance
+Vavg=(VL1+VL2+VL3)/3; // Average line voltage
+
+VD1=abs(VL1-Vavg); // Voltage deviation from the average
+VD2=abs(VL2-Vavg);
+VD3=abs(VL3-Vavg);
+VD=[VD1 VD2 VD3];
+VDMax=max(VD); // Choose maximum value of voltage deviation
+PerUBV=(VDMax/Vavg)*100;
+
+// (b) Expected approximate temp. rise if operating at rated load in a 40 deg
+PerDeltaT=2*PerUBV^2; // Percent change in temp.
+Tubv=Trated*(1+(PerDeltaT/100));
+
+// (c) Expected insulation life
+DeltaT=Tubv-Trated; // Percent increase in motor temp.
+RL=1/(2^(DeltaT/10)); // Relative life on insulation
+EL=RL*20;
+
+// (d) Required derating of motor to prevent shortening isulation life
+ReqDer=hp*0.92;
+
+// Display result on command window
+printf("\n Percent voltage unbalance = %0.2f ",PerUBV);
+printf("\n Expected approximate temperature rise = %0.0f deg C",Tubv);
+printf("\n Expected insulation life = %0.1f years",EL);
+printf("\n Required derating of motor = %0.1f hp",ReqDer);
+
diff --git a/3574/CH5/EX5.15/EX5_15.png b/3574/CH5/EX5.15/EX5_15.png Binary files differnew file mode 100644 index 000000000..092adcd01 --- /dev/null +++ b/3574/CH5/EX5.15/EX5_15.png diff --git a/3574/CH5/EX5.15/EX5_15.sce b/3574/CH5/EX5.15/EX5_15.sce new file mode 100644 index 000000000..fc7146168 --- /dev/null +++ b/3574/CH5/EX5.15/EX5_15.sce @@ -0,0 +1,38 @@ +// Example 5.15
+// Determine the machine parameters in ohms
+// Page No. 213
+
+clc;
+clear;
+close;
+
+// Given data
+V=460; // Motor voltage
+hp=50; // Motor horsepower
+r1=0.021; // Resistance
+r2=0.020;
+x1=0.100; // Reactance
+x2=0.0178;
+rfe=20;
+Xm=3.68; // Motor reactance
+
+// Machine parameters in ohms
+Vbase=V/sqrt(3); // Base voltage
+Pbase=hp*746/3; // Base power
+Zbase=Vbase^2/Pbase; // Base impedance
+
+R1=r1*Zbase;
+X1=x1*Zbase;
+R2=r2*Zbase;
+X2=x2*Zbase;
+Rfe=rfe*Zbase;
+XM=Xm*Zbase;
+
+// Display result on command window
+printf("\n Motor resistance 1 = %0.3f Ohm",R1);
+printf("\n Motor reactance 1 = %0.3f Ohm",X1);
+printf("\n Motor resistance 2 = %0.3f Ohm",R2);
+printf("\n Motor reactance 2 = %0.3f Ohm",X2);
+printf("\n Field resistance = %0.2f Ohm",Rfe);
+printf("\n Reactance of motor = %0.2f Ohm",XM);
+
diff --git a/3574/CH5/EX5.16/EX5_16.png b/3574/CH5/EX5.16/EX5_16.png Binary files differnew file mode 100644 index 000000000..8f260ea61 --- /dev/null +++ b/3574/CH5/EX5.16/EX5_16.png diff --git a/3574/CH5/EX5.16/EX5_16.sce b/3574/CH5/EX5.16/EX5_16.sce new file mode 100644 index 000000000..40f81e3ef --- /dev/null +++ b/3574/CH5/EX5.16/EX5_16.sce @@ -0,0 +1,65 @@ +// Example 5.16
+// Determine (a) R1, R2, X1, X2, XM and the combined core, friction and windage
+// loss (b) Express the no-load current as a percent of rated current
+// Page No. 218
+
+clc;
+clear;
+close;
+
+// Given data
+P3ph=2573.4; // 3-ph power of induction motor
+Vline=36.2; // Line voltage
+Iline=58; // Line current
+P3phnl=4664.4; // No load power
+Vlinenl=460; // No load line volatge
+Ilinenl=32.7; // No load line current
+Vdc=12; // DC voltage
+Idc=59; // DC current
+F1=60; // Rated frequency
+F2=15; // Test frequency
+Irated=57.8; // Rated current
+
+// (a) R1, R2, X1, X2, XM and the combined core, friction and windage loss
+Pbr15=P3ph/3; // Power/phase
+Vbr15=Vline/sqrt(3); // Voltage/phase
+Ibr15=Iline;
+PNL=P3phnl/3; // No load power/phase
+VNL=Vlinenl/sqrt(3); // No load voltage/phase
+INL=Ilinenl; // No load current/phase
+
+// Determination of R1
+Rdc=Vdc/Idc;
+R1=Rdc/2;
+
+// Determination of R2
+Zbr15=Vbr15/Ibr15; // Impedance
+Rbr15=Pbr15/Ibr15^2;
+R2=Rbr15-R1;
+
+// Determination of X1 and X2
+Xbr15=sqrt(Zbr15^2-Rbr15^2);
+Xbr60=Xbr15*(F1/F2);
+X1=0.4*Xbr60; // From Table 5.10
+X2=0.6*Xbr60;
+
+// Determination of XM
+SNL=VNL*INL;
+QNL=sqrt(SNL^2-PNL^2);
+XNL=QNL/INL^2;
+XM=XNL-X1;
+
+// Determination of combined friction, windage and core loss
+Ploss=PNL-(INL^2*R1);
+
+// (b) No-load current as a percent of rated current
+PerINL=INL*100/Irated;
+
+// Display result on command window
+printf("\n Motor resistance 1 = %0.3f Ohm/phase",R1);
+printf("\n Motor reactance 1 = %0.4f Ohm/phase",X1);
+printf("\n Motor resistance 2 = %0.3f Ohm/phase",R2);
+printf("\n Motor reactance 2 = %0.4f Ohm/phase",X2);
+printf("\n Reactance of motor = %0.2f Ohm/phase",XM);
+printf("\n Combined friction, windage and core loss = %0.0f W/phase",Ploss);
+printf("\n No-load current as a percent of rated current = %0.1f Percent",PerINL);
diff --git a/3574/CH5/EX5.17/EX5_17.png b/3574/CH5/EX5.17/EX5_17.png Binary files differnew file mode 100644 index 000000000..d2d2db027 --- /dev/null +++ b/3574/CH5/EX5.17/EX5_17.png diff --git a/3574/CH5/EX5.17/EX5_17.sce b/3574/CH5/EX5.17/EX5_17.sce new file mode 100644 index 000000000..f8e303f7d --- /dev/null +++ b/3574/CH5/EX5.17/EX5_17.sce @@ -0,0 +1,85 @@ +// Example 5.17
+// Determine the active power that the motor, driven as an induction generator
+// delivers to the system.
+// Page No. 223
+
+clc;
+clear;
+close;
+
+// Given data
+ns=1200; // Speed
+nr=1215;
+R1=0.200; // Motor resistance
+R2=0.250;
+X1=1.20; // Motor reactance
+X2=1.29;
+Rfe=317; // Field resistance
+XM=42; // Motor reactance
+V=460; // Voltage rating
+
+// Active power of the motor computation
+s=(ns-nr)/ns; // Speed difference
+Z2=(R2/s)+%i*X2;
+
+// Complex to Polar form...
+Z2_Mag=sqrt(real(Z2)^2+imag(Z2)^2); // Magnitude part
+Z2_Ang = atan(imag(Z2),real(Z2))*180/%pi; // Angle part
+
+Z0_Num_Mag=Rfe*XM; // Z0 numerator
+Z0_Num_Ang=0+90;
+
+Z0_Den_R=Rfe; // Z0 denominator
+Z0_Den_I=XM;
+Z0_Den=Z0_Den_R+%i*Z0_Den_I;
+// Complex to Polar form...
+Z0_Den_Mag=sqrt(real(Z0_Den)^2+imag(Z0_Den)^2); // Magnitude part
+Z0_Den_Ang = atan(imag(Z0_Den),real(Z0_Den))*180/%pi; // Angle part
+
+Z0_Mag=Z0_Num_Mag/Z0_Den_Mag; // Magnitude of Z0
+Z0_Ang=Z0_Num_Ang-Z0_Den_Ang; // Angle of Z0
+
+// Polar to Complex form
+Z0_R=Z0_Mag*cos(-Z0_Ang*%pi/180); // Real part of complex number
+Z0_I=Z0_Mag*sin(Z0_Ang*%pi/180); // Imaginary part of complex number
+
+// ZP computation
+ZP_Num_Mag=Z2_Mag*Z0_Mag; // ZP numerator magnitude
+ZP_Num_Ang=Z2_Ang+Z0_Ang; // ZP numerator angle
+
+ZP_Den_R=real(Z2)+Z0_R; // Real part of ZP denominator
+ZP_Den_I=imag(Z2)+Z0_I;
+ZP_Den=ZP_Den_R+%i*ZP_Den_I; // ZP in complex form
+
+// Complex to Polar form...
+ZP_Den_Mag=sqrt(real(ZP_Den)^2+imag(ZP_Den)^2); // Magnitude part
+ZP_Den_Ang = atan(imag(ZP_Den),real(ZP_Den))*180/%pi; // Angle part
+
+ZP_Mag=ZP_Num_Mag/ZP_Den_Mag; // Final vlaue of ZP in polar form
+ZP_Ang=ZP_Num_Ang-ZP_Den_Ang;
+// Polar to Complex form
+ZP_R=ZP_Mag*cos(-ZP_Ang*%pi/180); // Real part of complex number
+ZP_I=ZP_Mag*sin(ZP_Ang*%pi/180); // Imaginary part of complex number
+
+// Zin computation
+ZP=ZP_R+%i*ZP_I; // Parallel impedance
+Z1=R1+%i*X1;
+Zin=Z1+ZP; // Input impedance
+// Complex to Polar form...
+Zin_Mag=sqrt(real(Zin)^2+imag(Zin)^2); // Magnitude part
+Zin_Ang = atan(imag(Zin),real(Zin))*180/%pi; // Angle part
+
+// I1 computation
+I1_Mag=(V/sqrt(3))/Zin_Mag; // I1 magnitude
+I1_Ang=0-Zin_Ang; // I1 angle
+
+// S computation
+S_Mag=3*(V/sqrt(3))*I1_Mag; // S magnitude
+S_Ang=0-(-Zin_Ang); // S angle
+
+// Polar to Complex form
+S_R=S_Mag*cos(-S_Ang*%pi/180); // Real part of complex number
+S_I=S_Mag*sin(S_Ang*%pi/180); // Imaginary part of complex number
+
+// Display result on command window
+printf("\n Active power of the motor = %0.0f W",S_R);
diff --git a/3574/CH5/EX5.18/EX5_18.png b/3574/CH5/EX5.18/EX5_18.png Binary files differnew file mode 100644 index 000000000..6d9e3e903 --- /dev/null +++ b/3574/CH5/EX5.18/EX5_18.png diff --git a/3574/CH5/EX5.18/EX5_18.sce b/3574/CH5/EX5.18/EX5_18.sce new file mode 100644 index 000000000..4d5a3b810 --- /dev/null +++ b/3574/CH5/EX5.18/EX5_18.sce @@ -0,0 +1,44 @@ +// Example 5.18 +// Computation of (a) Locked rotor torque and the expected average in rush +// current (b) Repeat part (a) assuming motor is started at reduced voltage +// with 65% tap (c) In rush line current line current when starting at reduced +// voltage +// Page No. 231 + +clc; +clear all; +close; + +// Given data +P=125; // Rated Voltage +n=1141; // Speed of machine +hp=125; // Horsepower rating of device +Vline=460; // Line voltage +ns=1200; // Stator speed +s=0.125; // Slip +ILS=683; // Current at low side + +// (a) Locked rotor torque and the expected average in rush current +Trated=P*5252/(n); // Rated torque +Tlr=1.25*Trated; // Locked rotor torque +kVA=(6.3+7.1)/2; +Ilr=(kVA*1000*hp)/(Vline*sqrt(3)); // In-rush current + +// (b) Locked rotor torque and the expected average in rush current when motor +// is started at reduced voltage +V2=0.65*Vline; // Voltage impressed across the stator +I=Ilr*0.65; // Average in-rush current +T2=Tlr*(V2/Vline)^2; // Locked rotor toreque +nr=ns*(1-s); + +// (c) In rush line current line current when starting at reduced voltage +a=1/0.65; // Bank ratio of autotransformer +IHS=ILS/a; + +// Display result on command window +printf("\n Locked rotor torque = %0.1f lb-ft ",Tlr); +printf("\n Expected average in-rush current = %0.0f A ",Ilr); +printf("\n Locked rotor torque when motor is started at reduced voltage = %0.1f lb-ft ",T2); +printf("\n In-rush line current = %0.0f A",IHS); + + diff --git a/3574/CH5/EX5.19/EX5_19.png b/3574/CH5/EX5.19/EX5_19.png Binary files differnew file mode 100644 index 000000000..594d30e2e --- /dev/null +++ b/3574/CH5/EX5.19/EX5_19.png diff --git a/3574/CH5/EX5.19/EX5_19.sce b/3574/CH5/EX5.19/EX5_19.sce new file mode 100644 index 000000000..47f9361b6 --- /dev/null +++ b/3574/CH5/EX5.19/EX5_19.sce @@ -0,0 +1,41 @@ +// Example 5.19 +// Computation of (a) Locked rotor current per phase and minimum locked rotor +// torque when starting (b) Locked rotor current per phase when motor is delta +// connected (c) Code letter +// Page No.233 + +clc; +clear all; +close; + +// Given data +V=460; // Rated Voltage +Z=0.547; // Locked rotor impedance +n=1750; // Speed of machine +hp=60; // Horsepower rating of device +f=60; // Frequency of motor + + +// (a) Locked rotor current per phase and minimum locked rotor torque +Vphase=V/sqrt(3); // Voltage/phase +Ilr1=Vphase/Z; // Locked rotor current/phase +Trated=hp*5252/(n); // Rated torque +Tlr=1.4*Trated; // Locked rotor torque +T2=Tlr*(Vphase/V)^2; + +// (b) Locked rotor current per phase when motor is delta connected +Ilr=V/Z; // Locked rotor current/phase +Il=Ilr*sqrt(3); // Line current + +// (c) Code letter +Slr=sqrt(3)*V*Il/1000; // Code letter at rated voltage +kVA=Slr/f; + +// Display result on command window + +printf("\n Locked rotor current per phase = %0.1f A",Ilr1); +printf("\n Minimum locked rotor torque = %0.0f lb-ft",T2); +printf("\n Locked rotor current per phase when motor is delta connected = %0.0f A ",Il); +printf("\n Code letter = %0.1f",kVA); + + diff --git a/3574/CH5/EX5.2/EX5_2.png b/3574/CH5/EX5.2/EX5_2.png Binary files differnew file mode 100644 index 000000000..e3097ef0b --- /dev/null +++ b/3574/CH5/EX5.2/EX5_2.png diff --git a/3574/CH5/EX5.2/EX5_2.sce b/3574/CH5/EX5.2/EX5_2.sce new file mode 100644 index 000000000..8e4e4692d --- /dev/null +++ b/3574/CH5/EX5.2/EX5_2.sce @@ -0,0 +1,146 @@ +// Example 5.2
+// Determine (a) Slip (b) Line current (c) Apparent power, active power,
+// reactive power and power factor of the motor (d) Equivalent rotor curret
+// (e) Stator copper loss (f) Rotor copper loss (g) Core loss (h) Air-gap
+// power (i) Mechanical power developed (j) Developed torque (k) Shaft
+// horsepower (l) Shaft torque (m) Effiency
+// Page No. 180
+
+clc;
+clear;
+close;
+
+// Given data
+f=60; // Frequency
+P=6; // Number of poles
+nr=1185;
+R1=0.200; // Motor resistance
+R2=0.250;
+X1=1.20; // Motor reactance
+X2=1.29;
+Rfe=317; // Field resistance
+XM=42; // Motor reactance
+V=460; // Voltage rating
+PFPS=166; // Stray loss
+
+// (a) Slip
+ns=(120*f)/P;
+s=(ns-nr)/ns; // Speed difference
+
+// (b) Line current
+Z2=(R2/s)+%i*X2;
+// Complex to Polar form...
+Z2_Mag=sqrt(real(Z2)^2+imag(Z2)^2); // Magnitude part
+Z2_Ang = atan(imag(Z2),real(Z2))*180/%pi; // Angle part
+
+Z0_Num_Mag=Rfe*XM; // Z0 numerator
+Z0_Num_Ang=0+90;
+
+Z0_Den_R=Rfe; // Z0 denominator
+Z0_Den_I=XM;
+Z0_Den=Z0_Den_R+%i*Z0_Den_I;
+// Complex to Polar form...
+Z0_Den_Mag=sqrt(real(Z0_Den)^2+imag(Z0_Den)^2); // Magnitude part
+Z0_Den_Ang = atan(imag(Z0_Den),real(Z0_Den))*180/%pi; // Angle part
+
+Z0_Mag=Z0_Num_Mag/Z0_Den_Mag; // Magnitude of Z0
+Z0_Ang=Z0_Num_Ang-Z0_Den_Ang; // Angle of Z0
+
+// Polar to Complex form
+Z0_R=Z0_Mag*cos(-Z0_Ang*%pi/180); // Real part of complex number
+Z0_I=Z0_Mag*sin(Z0_Ang*%pi/180); // Imaginary part of complex number
+
+// ZP computation
+ZP_Num_Mag=Z2_Mag*Z0_Mag; // ZP numerator magnitude
+ZP_Num_Ang=Z2_Ang+Z0_Ang; // ZP numerator angle
+
+ZP_Den_R=real(Z2)+Z0_R; // Real part of ZP denominator
+ZP_Den_I=imag(Z2)+Z0_I;
+ZP_Den=ZP_Den_R+%i*ZP_Den_I; // ZP in complex form
+
+// Complex to Polar form...
+ZP_Den_Mag=sqrt(real(ZP_Den)^2+imag(ZP_Den)^2); // Magnitude part
+ZP_Den_Ang = atan(imag(ZP_Den),real(ZP_Den))*180/%pi; // Angle part
+
+ZP_Mag=ZP_Num_Mag/ZP_Den_Mag; // Final vlaue of ZP in polar form
+ZP_Ang=ZP_Num_Ang-ZP_Den_Ang;
+// Polar to Complex form
+ZP_R=ZP_Mag*cos(-ZP_Ang*%pi/180); // Real part of complex number
+ZP_I=ZP_Mag*sin(ZP_Ang*%pi/180); // Imaginary part of complex number
+
+// Zin computation
+ZP=ZP_R+%i*ZP_I; // Parallel impedance
+Z1=R1+%i*X1;
+Zin=Z1+ZP; // Input impedance
+// Complex to Polar form...
+Zin_Mag=sqrt(real(Zin)^2+imag(Zin)^2); // Magnitude part
+Zin_Ang = atan(imag(Zin),real(Zin))*180/%pi; // Angle part
+
+// I1 computation
+I1_Mag=(V/sqrt(3))/Zin_Mag; // I1 magnitude
+I1_Ang=0-Zin_Ang; // I1 angle
+
+// (c) Apparent power, active power, reactive power and power factor of the motor
+S_Mag=3*(V/sqrt(3))*I1_Mag; // S magnitude
+S_Ang=0-(-Zin_Ang); // S angle
+
+// Polar to Complex form
+S_R=S_Mag*cos(-S_Ang*%pi/180); // Real part of complex number
+S_I=S_Mag*sin(S_Ang*%pi/180); // Imaginary part of complex number
+
+FP=cosd(S_Ang); // Power factor
+
+// (d) Equivalent rotor curret
+E2_Mag=I1_Mag*ZP_Mag; // E2 magnitude
+E2_Ang=I1_Ang+ZP_Ang; // E2 angle
+
+I2_Mag=E2_Mag/Z2_Mag; // I2 magnitude
+I2_Ang=E2_Ang-Z2_Ang; // I2 angle
+
+// (e) Stator copper loss
+Pscl=3*I1_Mag^2*R1;
+
+// (f) Rotor copper loss
+Prel=3*I2_Mag^2*R2;
+
+// (g) Core loss
+Pcore=3*(E2_Mag^2/Rfe);
+
+// (h) Air-gap power
+Pgap=Prel/s;
+
+// (i) Mechanical power developed
+Pmech=Prel*(1-s)/s;
+
+// (j) Developed torque
+TD=(21.12*I2_Mag^2*R2)/(s*ns);
+
+// (k) Shaft horsepower
+LOSS=Pscl+Prel+Pcore+PFPS;
+Pshaft=(S_R-LOSS)/746;
+
+// (l) Shaft torque
+T=5252*Pshaft/nr;
+
+// (m) Effiency
+eta=Pshaft/S_R*746;
+
+// Display result on command window
+printf("\n Slip = %0.4f ",s);
+printf("\n Line current magnitude = %0.4f A",I1_Mag);
+printf("\n Line current angle = %0.4f deg",I1_Ang);
+printf("\n Apparent power = %0.0f W",S_R);
+printf("\n Active power = %0.0f var",S_I);
+printf("\n Reactive power = %0.0f VA",S_Mag);
+printf("\n Power factor of the motor = %0.3f ",FP);
+printf("\n Equivalent rotor curret magnitude = %0.4f A",I2_Mag);
+printf("\n Equivalent rotor curret angle = %0.4f deg",I2_Ang);
+printf("\n Stator copper loss = %0.0f W",Pscl);
+printf("\n Rotor copper loss = %0.0f W",Prel);
+printf("\n Core loss = %0.0f W",Pcore);
+printf("\n Air-gap power = %0.0f W",Pgap);
+printf("\n Mechanical power developed = %0.0f W",Pmech);
+printf("\n Developed torque = %0.2f lb-ft",TD);
+printf("\n Shaft horsepower = %0.2f hp",Pshaft);
+printf("\n Shaft torque = %0.1f lb-ft",T);
+printf("\n Effiency = %0.3f",eta);
diff --git a/3574/CH5/EX5.20/EX5_20.png b/3574/CH5/EX5.20/EX5_20.png Binary files differnew file mode 100644 index 000000000..ec482cc3d --- /dev/null +++ b/3574/CH5/EX5.20/EX5_20.png diff --git a/3574/CH5/EX5.20/EX5_20.sce b/3574/CH5/EX5.20/EX5_20.sce new file mode 100644 index 000000000..e6f7966fa --- /dev/null +++ b/3574/CH5/EX5.20/EX5_20.sce @@ -0,0 +1,38 @@ +// Example 5.20 +// Computation of (a) Resistance of the resistors required to limit the locked +// rotor current to 3 times rated current (b) Stator voltage per phase at +// locked rotor (c) Expected minimum locked rotor torque when starting as a +// percent of rated torque +// Page No. 235 + +clc; +clear all; +close; + +// Given data +Ilr=3*78; // Locked rotor current +Vbranch=132.79; // Branch voltage +Rlr=0.2549; //Locked rotor resistance +Xlr=0.0978; //Locked rotor impedance +f=60; //Frequency of motor +Zlr=0.273; + +// (a) Resistance of the resistors required to limit the locked rotor current +// to 3 times rated current +Rex=sqrt((Vbranch^2/Ilr^2)-(Rlr^2))-Xlr; + +// (b) Stator voltage per phase at locked rotor +IZlr=Ilr*Zlr; +VT1_N=IZlr; + +// (c) Expected minimum locked rotor torque when starting as a percent of +// rated torque +// From table 5.1 --> Minimum locked rotor torque = 150% rated torque + +// Display result on command window + +printf("\n Resistance of the resistors required = %0.4f Ohm ",Rex); +printf("\n Stator voltage per phase at locked rotor = %0.2f V ",VT1_N); +disp('Expected minimum locked rotor torque = 1.5 Trated'); + + diff --git a/3574/CH5/EX5.21/EX5_21.png b/3574/CH5/EX5.21/EX5_21.png Binary files differnew file mode 100644 index 000000000..f18df762a --- /dev/null +++ b/3574/CH5/EX5.21/EX5_21.png diff --git a/3574/CH5/EX5.21/EX5_21.sce b/3574/CH5/EX5.21/EX5_21.sce new file mode 100644 index 000000000..b6893e689 --- /dev/null +++ b/3574/CH5/EX5.21/EX5_21.sce @@ -0,0 +1,34 @@ +// Example 5.21 +// Computation of Inductance and voltage rating of each series connected +// inductor required to limit the starting current to approximately 2*Irated. +// Page No. 236 + +clc; +clear all; +close; + +// Given data +KVA=6.7; // Average locked rotor KVA/hp +hp=7.5; // Motor horsepower +Vline=208; // Line voltage +I=48; // Total current +Rlr=0.294; // Locked rotor resistance +Xlr=0.809; // Locked rotor impedance +f=60; // Frequency of motor + +// Corresponding approximate load current +Ilr=KVA*1000*hp/(sqrt(3)*Vline); +Vphase=Vline/sqrt(3); // Voltage/phase + +// Applying ohm's law to one phase +Zlr=Vphase/Ilr; // Impedance +Xex=sqrt((Vphase^2/I^2)-(Rlr^2))-Xlr; +L=Xex/(2*%pi*f); +L=L*10^03; +VXl=I*Xex; + +// Display result on command window +printf("\n The inductance of each series connected inductor = %0.2f mH ",L); +printf("\n The voltage rating of each series connected inductor = %0.1f V ",VXl); + + diff --git a/3574/CH5/EX5.3/EX5_3.png b/3574/CH5/EX5.3/EX5_3.png Binary files differnew file mode 100644 index 000000000..99c03fad4 --- /dev/null +++ b/3574/CH5/EX5.3/EX5_3.png diff --git a/3574/CH5/EX5.3/EX5_3.sce b/3574/CH5/EX5.3/EX5_3.sce new file mode 100644 index 000000000..3bd189876 --- /dev/null +++ b/3574/CH5/EX5.3/EX5_3.sce @@ -0,0 +1,38 @@ +// Example 5.3
+// Computation of (a) Speed at which maximum torque is developed (b) Maximum
+// torque that the machine can develop (c) Rated shaft torque (d) Which NEMA
+// design fits this motor?
+// Page No. 184
+
+clc;
+clear;
+close;
+
+// Given data
+f=60; // Frequency in Hz
+p=4; // Number of poles
+hp=40; // Horsepower
+n=1751; // Rated speed of machine
+v=460/sqrt(3); // Voltage
+s=0.1490; // Slip
+R2=0.153; // Rotor resistance
+R1=0.102;
+X1=0.409; // Rotor reactance
+X2=0.613;
+
+// (a) Speed at which maximum torque is developed
+STDmax=R2/(sqrt(R1^2+(X1+X2)^2));
+ns=120*f/p; //stator spped
+nr=ns*(1-s);
+
+// (b) Maximum torque that the machine can develop
+TDmax=(21.12*v^2)/(2*ns*(sqrt(R1^2+(X1+X2)^2)+R1));
+
+// (c) Rated shaft torque
+TDshaft=hp*5252/n;
+
+// Display result on command window
+printf("\n Speed at which maximum torque is developed = %0.0f r/min ",nr);
+printf("\n Maximum torque that the machine can develop = %0.1f lb-ft ",TDmax);
+printf("\n Rated shaft torque = %0.1f lb-ft ",TDshaft);
+printf("\n Maximum torque is developed at slip of 0.1490 and \n hence machine is placed in design A category ");
diff --git a/3574/CH5/EX5.4/EX5_4.png b/3574/CH5/EX5.4/EX5_4.png Binary files differnew file mode 100644 index 000000000..b125ce6ce --- /dev/null +++ b/3574/CH5/EX5.4/EX5_4.png diff --git a/3574/CH5/EX5.4/EX5_4.sce b/3574/CH5/EX5.4/EX5_4.sce new file mode 100644 index 000000000..4cfdeb7fd --- /dev/null +++ b/3574/CH5/EX5.4/EX5_4.sce @@ -0,0 +1,39 @@ +// Example 5.4
+// Computation of (a) Amount of torque that must be removed from the motor
+// shaft to maintain 1760r/min (b) Expected minimum startimg torque for the
+// lower voltage (c) Percent change in developed torque caused by 10% drop in
+// system voltage.
+// Page No. 185
+
+clc;
+clear;
+close;
+
+// Given data
+
+hp=50; // Horsepower
+n=1760; // Rated speed of machine
+v1=460;
+
+
+// (a) Amount of torque that must be removed from the motor shaft to maintain
+// 1760r/min
+v2=v1*0.90;
+Trated=hp*5252/n; //Rated torque
+TD2=Trated*(v2/v1)^2;
+Treduction=Trated-TD2;
+
+// (b) Expected minimum startimg torque for the lower voltage
+
+Tlr=1.40*Trated;
+Tlr2=Tlr*(v2/v1)^2;
+
+// (c) Percent change in developed torque caused by 10% drop in system voltage
+
+Tchange=(TD2-Trated)/Trated;
+Tchanger=(Tlr2-Tlr)/Tlr;
+
+// Display result on command window
+printf("\n Amount of torque that must be removed from the motor shaft = %0.1f lb-ft",Treduction);
+printf("\n Expected minimum starting torque for the lower voltage = %0.1f lb-ft ",Tlr2);
+printf("\n Percent change in developed torque = %0.0f Percent ",Tchanger*100);
diff --git a/3574/CH5/EX5.5/EX5_5.png b/3574/CH5/EX5.5/EX5_5.png Binary files differnew file mode 100644 index 000000000..ab613c387 --- /dev/null +++ b/3574/CH5/EX5.5/EX5_5.png diff --git a/3574/CH5/EX5.5/EX5_5.sce b/3574/CH5/EX5.5/EX5_5.sce new file mode 100644 index 000000000..d10f548e1 --- /dev/null +++ b/3574/CH5/EX5.5/EX5_5.sce @@ -0,0 +1,30 @@ +// Example 5.5
+// Computation of minimum value of (a) Shaft speed (b) Rotor current referred
+// to the stator
+// Page No. 187
+
+clc;
+clear;
+close;
+
+// Given data
+f=60; // Frequency in Hz
+p=12; // Number of poles
+nr=591.1; // Rated speed of machine
+v=575; // Voltage rating of the machine
+R2=0.055;
+
+// (a) Shaft speed
+ns=120*f/p; // Speed (r/min)
+s1=(ns-nr)/ns; // Slip 1
+s2=1.25*s1; // Slip 2
+nr1=ns*(1-s2);
+
+// (b) Rotor current referred to the stator
+V=v/sqrt(3);
+I2=V*s2/R2;
+
+// Display result on command window
+printf("\n Shaft speed = %0.0f r/min ",nr1);
+printf("\n Rotor current referred to the stator = %0.0f A ",I2);
+
diff --git a/3574/CH5/EX5.6/EX5_6.png b/3574/CH5/EX5.6/EX5_6.png Binary files differnew file mode 100644 index 000000000..307395ae7 --- /dev/null +++ b/3574/CH5/EX5.6/EX5_6.png diff --git a/3574/CH5/EX5.6/EX5_6.sce b/3574/CH5/EX5.6/EX5_6.sce new file mode 100644 index 000000000..7fe573b8d --- /dev/null +++ b/3574/CH5/EX5.6/EX5_6.sce @@ -0,0 +1,36 @@ +// Example 5.6
+// Determine (a) New operating speed if a system disturbance causes a 10% drop
+// in voltage and 6% drop in frequency (b) New shaft horsepower.
+// Page No. 190
+
+clc;
+clear;
+close;
+
+// Given data
+etaV=0.90; // Efficiency related to voltage
+V=230; // Voltage
+etaF=0.94; // Efficiency related to voltage
+f=60; // Frequency
+N=6; // Number of poles
+nr1=1175; // Speed of motor
+P=20; // Horsepower of motor
+
+// (a) New operating speed if a system disturbance causes a 10% drop in
+// voltage and 6% drop in frequency
+V2=etaV*V; // New voltage after 10% drop
+f2=etaF*f; // New frequency after 6% drop
+ns1=120*f/N;
+ns2=120*0.94*f/N;
+s1=(ns1-nr1)/ns1; // Speed difference
+
+s2=s1*((V/V2)^2)*(f2/f);
+nr2=ns2*(1-s2); // New speed
+
+// (b) New shaft horsepower
+P2=P*(nr2/nr1); // With a constant torque load T2=T1
+
+// Display result on command window
+printf("\n New operating speed in case of voltage and frequency drop = %0.0f r/min ",nr2);
+printf("\n New shaft horsepower = %0.1f hp ",P2);
+
diff --git a/3574/CH5/EX5.7/EX5_7.png b/3574/CH5/EX5.7/EX5_7.png Binary files differnew file mode 100644 index 000000000..ea716da08 --- /dev/null +++ b/3574/CH5/EX5.7/EX5_7.png diff --git a/3574/CH5/EX5.7/EX5_7.sce b/3574/CH5/EX5.7/EX5_7.sce new file mode 100644 index 000000000..81ebcf6cc --- /dev/null +++ b/3574/CH5/EX5.7/EX5_7.sce @@ -0,0 +1,22 @@ +// Example 5.7
+// Determine expected locked-rotor line current
+// Page No. 192
+
+clc;
+clear;
+close;
+
+// Given data
+Ir1=151; // Rated current
+V1=230; // Rated voltage
+V2=220; // Motor starting voltage
+F1=60; // Rated frequency
+F2=50; // Motor starting frequency
+
+// Expected locked-rotor line current
+Ir2=Ir1*((V2/F2)/(V1/F1));
+
+// Display result on command window
+printf("\n Expected locked-rotor line current = %0.0f A ",Ir2);
+
+
diff --git a/3574/CH5/EX5.8/EX5_8.png b/3574/CH5/EX5.8/EX5_8.png Binary files differnew file mode 100644 index 000000000..f0efe979c --- /dev/null +++ b/3574/CH5/EX5.8/EX5_8.png diff --git a/3574/CH5/EX5.8/EX5_8.sce b/3574/CH5/EX5.8/EX5_8.sce new file mode 100644 index 000000000..915351ce4 --- /dev/null +++ b/3574/CH5/EX5.8/EX5_8.sce @@ -0,0 +1,29 @@ +// Example 5.8
+// Determine (a) Expected minimum locked-rotor torque (b) Repeat (a) when
+// voltage and frequency dropped to 230V and 58Hz
+// Page No. 193
+
+clc;
+clear;
+close;
+
+// Given data
+HPrated=75; // Rated horsepower
+nrated=1750; // Rated speed
+V1=240; // Rated voltage
+V2=230; // Voltage after drop
+F1=60; // Rated frequency
+F2=58; // Frequency after drop
+
+// (a) Expected minimum locked-rotor torque
+Trated=5252*HPrated/nrated; // Rated torque
+Tlr=Trated*1.2; // Minimum locked-rotor torque is 120% rated
+
+// (b) Expected minimum locked-rotor torque when voltage and frequency dropped
+// to 230V and 58Hz
+Tlr2=Tlr*((V2/F2)^2)*((F1/V1)^2);
+
+// Display result on command window
+printf("\n Expected minimum locked-rotor torque = %0.0f lb-ft",Tlr);
+printf("\n Expected minimum locked-rotor torque after drop = %0.0f lb-ft",Tlr2);
+
diff --git a/3574/CH5/EX5.9/EX5_9.png b/3574/CH5/EX5.9/EX5_9.png Binary files differnew file mode 100644 index 000000000..dc11e323b --- /dev/null +++ b/3574/CH5/EX5.9/EX5_9.png diff --git a/3574/CH5/EX5.9/EX5_9.sce b/3574/CH5/EX5.9/EX5_9.sce new file mode 100644 index 000000000..1915fa0f4 --- /dev/null +++ b/3574/CH5/EX5.9/EX5_9.sce @@ -0,0 +1,37 @@ +// Example 5.9
+// Determine (a) Shaft r/min (b) Slip
+// Page No. 194
+
+clc;
+clear;
+close;
+
+// Given data
+F1=60; // Rated frequency
+N=4; // Number of poles
+F2=50; // New frequency
+ns=1770; // Rated speed
+
+// (a) Shaft r/min
+ns60=120*F1/N; // Speed at rated ferquency
+ns50=120*F2/N; // Speed at 50 Hz frequency
+s60=(ns60-ns)/ns60; // Slip at 60 Hz frequency
+
+// Using eq. (5.16) and by solving..s50=29.251/nr50
+// Using eq. (4.3) and solving for nr50 we get the quadratic equation..
+// Using various values of quadratic equations, we have
+a=1;
+b=-1500;
+c=43876.5;
+r1=(-b+sqrt(b^2-4*a*c))/(2*a); // Root 1
+
+r2=(-b-sqrt(b^2-4*a*c))/(2*a); // Root 2
+// Answer 'r2' is not valid
+
+// (b) Slip
+s50=(ns50-r1)/ns50;
+
+// Display result on command window
+printf("\n Shaft speed = %0.0f r/min",r1);
+printf("\n Slip = %0.3f ",s50);
+
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