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diff --git a/1092/CH8/EX8.10/Example8_10.sce b/1092/CH8/EX8.10/Example8_10.sce new file mode 100755 index 000000000..dfdd17198 --- /dev/null +++ b/1092/CH8/EX8.10/Example8_10.sce @@ -0,0 +1,56 @@ +// Electric Machinery and Transformers +// Irving L kosow +// Prentice Hall of India +// 2nd editiom + +// Chapter 8: AC DYNAMO TORQUE RELATIONS - SYNCHRONOUS MOTORS +// Example 8-10 + +clear; clc; close; // Clear the work space and console. + +// Given data +kVA = 10000 ; // kVA rating of a system +cos_theta = 0.65 ; // power factor of the system +sin_theta = sqrt( 1 - (cos_theta)^2 ); +cos_theta_b = 0.85 ; // Raised PF +sin_theta_b = sqrt( 1 - (cos_theta_b)^2 ); +cost = 60 ; // cost of the synchronous capacitor to improve the PF in dollars/kVA +// neglect the losses in the synchronous capacitor + +// Calculations +// case a : For unity PF +// at the original load +kW_a = kVA * cos_theta ; // +theta = acosd(cos_theta) ; // Power factor angle of the system in degrees +kvar = kVA * sind(theta) ; // Reactive power in kvar +kVA_a = kvar ; +cost_cap_a = kvar * cost ; // Cost of raising the PF to unity PF in dollars + +// case b +theta_b = acosd(cos_theta_b) ; // Power factor angle of the system in degrees +kVA_b = kW_a / cos_theta_b ; // kVA value reduction +kvar_b = kVA_b * sind(theta_b) ; // final kvar value reduced +kvar_add = kvar - kvar_b ; // kvar of correction added + +cost_cap_b = kvar_add * cost ; // Cost of raising the PF to 0.85 PF in dollars + +// Display the results + +disp("Example 8-10 Solution : "); +printf(" \n Note : Slight variations in the kvar and cost values are due to "); +printf(" \n non-approximation of theta values while calculating in scilab.\n"); +printf(" \n a: At the original load,\n"); +printf(" \n kW = %d kW at theta = %.1f degrees \n", kW_a , theta ); +printf(" \n kvar = %.3f kvar\n\n For unity PF,",kvar); +printf(" \n kVA of synchronous capacitor = %.3f kVA (neglecting losses)\n",kVA_a); +printf(" \n Cost of synchronous capacitor = $%.f \n\n",cost_cap_a ); + +printf(" \n b: For %.2f, PF = cos(%.1f), the total power,",cos_theta_b, theta_b); +printf(" \n %.f kW,remains the same. Therefore,\n ",kW_a); +printf(" \n kVA of final system reduced to = %.f kVA \n",kVA_b); +printf(" \n kvar of final system reduced to = %.f kvar \n Therefore,",kvar_b); + +printf(" \n kvar of correction added = %.3f kvar\n ",kvar_add); +printf(" \n kVA of synchronous capacitor = %.3f kVA (neglecting losses)\n",kvar_add); +printf(" \n Cost of synchronous capacitor = $%.f",cost_cap_b ); +printf(" \n or less than half the cost in part(a)"); |