diff options
Diffstat (limited to '3472/CH39')
33 files changed, 1040 insertions, 0 deletions
diff --git a/3472/CH39/EX39.1/Example39_1.sce b/3472/CH39/EX39.1/Example39_1.sce new file mode 100644 index 000000000..355c660d1 --- /dev/null +++ b/3472/CH39/EX39.1/Example39_1.sce @@ -0,0 +1,37 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.1 :
+// Page number 676
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+capital_cost_group = 8000.0 // Capital cost of group drive(Rs)
+n_single = 5.0 // Number of individual drive
+capital_cost_single = 2500.0 // Capital cost of individual drive(Rs)
+energy_cons_group = 40000.0 // Annual energy consumption of group drive(kWh)
+energy_cons_single = 30000.0 // Annual energy consumption of group drive(kWh)
+cost_energy = 8.0/100 // Cost of energy per kWh(Rs)
+dmo_group = 12.0 // Depreciation,maintenance & other fixed charges for group drive(%)
+dmo_single = 18.0 // Depreciation,maintenance & other fixed charges for individual drive(%)
+
+// Calculations
+// Case(a)
+annual_cost_energy_a = energy_cons_group*cost_energy // Annual cost of energy(Rs)
+dmo_cost_a = capital_cost_group*dmo_group/100 // Depreciation,maintenance & other fixed charges per year for group drive(Rs)
+yearly_cost_a = annual_cost_energy_a+dmo_cost_a // Total yearly cost(Rs)
+// Case(b)
+total_cost = capital_cost_single*n_single // Capital cost of individual drive(Rs)
+annual_cost_energy_b = energy_cons_single*cost_energy // Annual cost of energy(Rs)
+dmo_cost_b = total_cost*dmo_single/100 // Depreciation,maintenance & other fixed charges per year for individual drive(Rs)
+yearly_cost_b = annual_cost_energy_b+dmo_cost_b // Total yearly cost(Rs)
+
+// Results
+disp("PART IV - EXAMPLE : 1.1 : SOLUTION :-")
+printf("\nTotal annual cost of group drive = Rs. %.f ", yearly_cost_a)
+printf("\nTotal annual cost of individual drive = Rs. %.f ", yearly_cost_b)
diff --git a/3472/CH39/EX39.10/Example39_10.sce b/3472/CH39/EX39.10/Example39_10.sce new file mode 100644 index 000000000..b187e2f4a --- /dev/null +++ b/3472/CH39/EX39.10/Example39_10.sce @@ -0,0 +1,33 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.10 :
+// Page number 687
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+V = 220.0 // DC shunt motor voltage(V)
+I_a1 = 50.0 // Armature current at 800rpm(A)
+N_1 = 800.0 // Speed of dc shunt motor(rpm)
+N_2 = 1000.0 // Speed of dc shunt motor with additional resistance(rpm)
+I_a2 = 75.0 // Armature current with additional resistance(A)
+R_a = 0.15 // Armature resistance(ohm)
+R_f = 250.0 // Field resistance(ohm)
+
+// Calculations
+E_b1 = V-R_a*I_a1 // Back emf at 800 rpm(V)
+I_f1 = V/R_f // Shunt field current(A)
+E_b2 = V-R_a*I_a2 // Back emf at 1000 rpm(V)
+I_f2 = E_b2*N_1*I_f1/(E_b1*N_2) // Shunt field current at 1000 rpm(A)
+R_f2 = V/I_f2 // Field resistance at 1000 rpm(ohm)
+R_add = R_f2-R_f // Additional resistance required(ohm)
+
+// Results
+disp("PART IV - EXAMPLE : 1.10 : SOLUTION :-")
+printf("\nAdditional resistance to be inserted in the field circuit to raise the speed = %.1f ohm\n", R_add)
+printf("\nNOTE: ERROR: Calculation mistake in E_b2 in the textbook solution")
diff --git a/3472/CH39/EX39.11/Example39_11.sce b/3472/CH39/EX39.11/Example39_11.sce new file mode 100644 index 000000000..84f2ed671 --- /dev/null +++ b/3472/CH39/EX39.11/Example39_11.sce @@ -0,0 +1,29 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.11 :
+// Page number 687
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+V = 220.0 // DC series motor voltage(V)
+I_1 = 20.0 // Armature current at 800rpm(A)
+N_1 = 800.0 // Speed of dc series motor(rpm)
+R_div = 0.4 // Diverter resistance(ohm)
+R_a = 0.5 // Armature resistance(ohm)
+R_f = 0.2 // Series field resistance(ohm)
+
+// Calculations
+E_b1 = V-(R_a+R_f)*I_1 // Back emf at 800 rpm(V)
+I_2 = I_1*R_div/(R_div+R_f) // Series field current at new speed(A)
+E_b2 = V-(R_a*I_1+R_f*I_2) // Back emf at new speed(V)
+N_2 = I_1*N_1*E_b2/(I_2*E_b1) // New speed with diverter(rpm)
+
+// Results
+disp("PART IV - EXAMPLE : 1.11 : SOLUTION :-")
+printf("\nSpeed of motor with a diverter connected in parallel with series field, N_2 = %.f rpm", N_2)
diff --git a/3472/CH39/EX39.12/Example39_12.sce b/3472/CH39/EX39.12/Example39_12.sce new file mode 100644 index 000000000..5a3fa1a82 --- /dev/null +++ b/3472/CH39/EX39.12/Example39_12.sce @@ -0,0 +1,25 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.12 :
+// Page number 687-688
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+speed_per = 15.0 // Motor speed increased by(%)
+
+// Calculations
+N_2 = (100+speed_per)/100 // New speed N_2(rpm)
+phi_2 = 1/N_2*100 // Flux_2 in terms of full load flux
+I_sc1 = 0.75 // New series field current in terms of I_a1
+I_a2 = N_2 // Armature current in terms of I_a1
+R_d = I_sc1/(I_a2-I_sc1)*100 // Diverter resistance in terms of series field resistance(%)
+
+// Results
+disp("PART IV - EXAMPLE : 1.12 : SOLUTION :-")
+printf("\nDiverter resistance, R_d = %.1f percent of field resistance", R_d)
diff --git a/3472/CH39/EX39.13/Example39_13.sce b/3472/CH39/EX39.13/Example39_13.sce new file mode 100644 index 000000000..0dd87cff1 --- /dev/null +++ b/3472/CH39/EX39.13/Example39_13.sce @@ -0,0 +1,28 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.13 :
+// Page number 689
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+V = 250.0 // Voltage of DC shunt motor(V)
+N_1 = 400.0 // No load speed(rpm)
+R_a = 0.5 // Armature resistance(ohm)
+N_2 = 200.0 // Speed with additional resistance(rpm)
+I_a = 20.0 // Armature current(A)
+
+// Calculations
+k_phi = (V-I_a*R_a)/N_1 // kΦ
+R = (V-k_phi*N_2)/I_a // Resistance(ohm)
+R_add = R-R_a // Additional resistance to be placed in armature circuit(ohm)
+
+// Results
+disp("PART IV - EXAMPLE : 1.13 : SOLUTION :-")
+printf("\nResistance to be placed in the armature circuit = %.f ohm\n", R_add)
+printf("\nNOTE: ERROR: The given data doesnt match with example 1.7 as mentioned in problem statement")
diff --git a/3472/CH39/EX39.14/Example39_14.sce b/3472/CH39/EX39.14/Example39_14.sce new file mode 100644 index 000000000..19171c727 --- /dev/null +++ b/3472/CH39/EX39.14/Example39_14.sce @@ -0,0 +1,33 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.14 :
+// Page number 689
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+V = 400.0 // Voltage of DC shunt motor(V)
+hp = 20.0 // Power of DC shunt motor(hp)
+I = 44.0 // Current drawn by motor(A)
+N_1 = 1000.0 // Speed(rpm)
+N_2 = 800.0 // Speed with additional resistance(rpm)
+R_sh = 200.0 // Shunt field resistance(ohm)
+
+// Calculations
+output = hp*746 // Motor output(W)
+I_f1 = V/R_sh // Shunt field current(A)
+I_a1 = I-I_f1 // Armature current(A)
+E_b1 = output/I_a1 // Back emf(V)
+R_a = (V-E_b1)/I_a1 // Armature resistance(ohm)
+I_a2 = I_a1*(N_2/N_1)**2 // Armature current at N2(A)
+E_b2 = N_2/N_1*E_b1 // Back emf at N2(V)
+r = ((V-E_b2)/I_a2)-R_a // Resistance connected in series with armature(ohm)
+
+// Results
+disp("PART IV - EXAMPLE : 1.14 : SOLUTION :-")
+printf("\nResistance to be connected in series with armature to reduce speed, r = %.2f ohm", r)
diff --git a/3472/CH39/EX39.15/Example39_15.sce b/3472/CH39/EX39.15/Example39_15.sce new file mode 100644 index 000000000..3189856f4 --- /dev/null +++ b/3472/CH39/EX39.15/Example39_15.sce @@ -0,0 +1,32 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.15 :
+// Page number 690
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+hp = 15.0 // Power of DC shunt motor(hp)
+V = 400.0 // Voltage of DC shunt motor(V)
+N_reduce = 20.0 // Speed is to be reduced by(%)
+I_f = 3.0 // Field current(A)
+R_a = 0.5 // Armature resistance(ohm)
+n = 0.85 // Efficiency of motor
+
+// Calculations
+motor_input = hp*746/n // Motor input(W)
+I = motor_input/V // Motor current(A)
+I_a1 = I-I_f // Armature current(A)
+I_a2 = I_a1 // Armature current at new speed(A)
+E_b1 = V-I_a1*R_a // Back emf(V)
+E_b2 = E_b1*(100-N_reduce)/100 // Back emf at new speed(V)
+r = ((V-E_b2)/I_a2)-R_a // Ohmic value of resistor connected in the armature circuit(ohm)
+
+// Results
+disp("PART IV - EXAMPLE : 1.15 : SOLUTION :-")
+printf("\nOhmic value of resistor connected in the armature circuit, r = %.2f ohm", r)
diff --git a/3472/CH39/EX39.16/Example39_16.sce b/3472/CH39/EX39.16/Example39_16.sce new file mode 100644 index 000000000..f290e6f98 --- /dev/null +++ b/3472/CH39/EX39.16/Example39_16.sce @@ -0,0 +1,28 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.16 :
+// Page number 697-698
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+p = 6.0 // Number of poles
+f = 50.0 // Frequency(Hz)
+R_2 = 0.3 // Rotor resistance per phase(ohm)
+N_1 = 960.0 // Rotor speed(rpm)
+N_2 = 800.0 // New rotor speed with external resistance(rpm)
+
+// Calculations
+N_s = 120*f/p // Synchronous speed(rpm)
+S_1 = (N_s-N_1)/N_s // Slip at full load
+S_2 = (N_s-N_2)/N_s // New slip
+R = (S_2/S_1*R_2)-R_2 // External resistance per phase added in rotor circuit to reduce speed(ohm)
+
+// Results
+disp("PART IV - EXAMPLE : 1.16 : SOLUTION :-")
+printf("\nExternal resistance per phase added in rotor circuit to reduce speed, R = %.1f ohm", R)
diff --git a/3472/CH39/EX39.17/Example39_17.sce b/3472/CH39/EX39.17/Example39_17.sce new file mode 100644 index 000000000..6c44ab73a --- /dev/null +++ b/3472/CH39/EX39.17/Example39_17.sce @@ -0,0 +1,37 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.17 :
+// Page number 699
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+hp = 50.0 // DC shunt motor rating(hp)
+V = 440.0 // Voltage(V)
+I_b = 150.0 // Breaking current(A)
+N_reduce = 40.0 // Speed of motor fallen by(%)
+R_a = 0.1 // Armature resistance(ohm)
+I_a_fl = 100.0 // Full-load armature current(A)
+N_fl = 600.0 // Full-load speed(rpm)
+
+// Calculations
+E_b = V-I_a_fl*R_a // Back emf of motor(V)
+V_a = V+E_b // Voltage across armature when braking starts(V)
+R_b = V_a/I_b // Resistance required(ohm)
+R_extra = R_b-R_a // Extra resistance required(ohm)
+T_fl = hp*746*60/(2*%pi*N_fl) // Full-load torque(N-m)
+T_initial_b = T_fl*I_b/I_a_fl // Initial breaking torque(N-m)
+E_b2 = E_b*(100-N_reduce)/100 // Back emf at new speed(V)
+I = (V+E_b2)/R_b // Current(A)
+EBT = T_fl*I/I_a_fl // Torque when motor speed reduced by 40%(N-m)
+
+// Results
+disp("PART IV - EXAMPLE : 1.17 : SOLUTION :-")
+printf("\nBraking torque = %.1f N-m", T_initial_b)
+printf("\nTorque when motor speed has fallen, E.B.T = %.1f N-m\n", EBT)
+printf("\nNOTE: ERROR: Calculation mistakes in the textbook solution")
diff --git a/3472/CH39/EX39.18/Example39_18.sce b/3472/CH39/EX39.18/Example39_18.sce new file mode 100644 index 000000000..b7be75add --- /dev/null +++ b/3472/CH39/EX39.18/Example39_18.sce @@ -0,0 +1,36 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.18 :
+// Page number 699-700
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+V = 400.0 // Voltage of IM(V)
+p = 4.0 // Number of poles
+f = 50.0 // Frequency(Hz)
+hp = 25.0 // Power developed(hp)
+S = 0.04 // Slip
+R_X_2 = 1.0/4 // Ratio of rotor resistance to standstill reactance i.e R2/X2
+
+// Calculations
+N_s = 120*f/p // Synchronous speed(rpm)
+N_fl = N_s*(1-S) // Full load speed(rpm)
+T_fl = hp*735.5*60/(2*%pi*N_fl*9.81) // Full-load torque(kg-m)
+S_1 = 1.0 // Slip at standstill
+X_R_2 = 1.0/R_X_2 // Ratio of standstill reactance to rotor resistance
+T_s_fl = S_1/S*((1+(S*X_R_2)**2)/(1+(S_1*X_R_2)**2)) // T_standstill/T_fl
+T_standstill = T_s_fl*T_fl // Standstill torque(kg-m)
+S_instant = (N_s+N_fl)/N_s // Slip at instant of plugging
+T_initial = (S_instant/S)*((1+(S*X_R_2)**2)/(1+(S_instant*X_R_2)**2))*T_fl // Initial plugging torque(kg-m)
+
+// Results
+disp("PART IV - EXAMPLE : 1.18 : SOLUTION :-")
+printf("\nInitial plugging torque = %.1f kg-m", T_initial)
+printf("\nTorque at standstill = %.f kg-m\n", T_standstill)
+printf("\nNOTE: ERROR: Calculation mistake from full-load torque onwards. Hence, change in obtained answer from that of textbook")
diff --git a/3472/CH39/EX39.19/Example39_19.sce b/3472/CH39/EX39.19/Example39_19.sce new file mode 100644 index 000000000..0e3ec5267 --- /dev/null +++ b/3472/CH39/EX39.19/Example39_19.sce @@ -0,0 +1,27 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.19 :
+// Page number 701
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+T = 312.5 // Load torque(N-m)
+N = 500.0 // Speed limit(rpm)
+R_total = 1.0 // Total resistance of armature & field(ohm)
+
+// Calculations
+input_load = 2*%pi*N*T/60 // Input from load(W)
+E = 345.0 // Voltage from magnetization curve(V). From Fig E1.5 page no 701
+I = 47.5 // Current from magnetization curve(A). From Fig E1.5 page no 701
+R = E/I // Resistance(ohm)
+R_add = R-R_total // Additional resistance required(ohm)
+
+// Results
+disp("PART IV - EXAMPLE : 1.19 : SOLUTION :-")
+printf("\nValue of resistance to be connected in motor circuit = %.2f ohm", R_add)
diff --git a/3472/CH39/EX39.2/Example39_2.sce b/3472/CH39/EX39.2/Example39_2.sce new file mode 100644 index 000000000..89227e8c0 --- /dev/null +++ b/3472/CH39/EX39.2/Example39_2.sce @@ -0,0 +1,29 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.2 :
+// Page number 680
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+I_sc = 6.0 // Short circuit current = 6 times full load current
+s_fl = 5.0 // Full load slip(%)
+tap = 60.0 // Auto-tranformer tapping(%)
+
+// Calculations
+// Case(a)
+I_s_fl_a = I_sc/3.0 // I_s/I_fl
+T_s_fl_a = I_s_fl_a**2*s_fl/100 // Starting torque in terms of full-load torque with star-delta starter
+// Case(b)
+I_s_fl_b = tap/100*I_sc // I_s/I_fl
+T_s_fl_b = I_s_fl_b**2*s_fl/100 // Starting torque in terms of full-load torque with auto-transformer starter
+
+// Results
+disp("PART IV - EXAMPLE : 1.2 : SOLUTION :-")
+printf("\nCase(a): Starting torque in terms of full-load torque with star-delta starter, I_s/I_fl = %.1f ", T_s_fl_a)
+printf("\nCase(b): Starting torque in terms of full-load torque with auto-transformer starter, I_s/I_fl = %.3f ", T_s_fl_b)
diff --git a/3472/CH39/EX39.20/Example39_20.sce b/3472/CH39/EX39.20/Example39_20.sce new file mode 100644 index 000000000..8020c90c2 --- /dev/null +++ b/3472/CH39/EX39.20/Example39_20.sce @@ -0,0 +1,31 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.20 :
+// Page number 702
+clear ; clc ; close ; // Clear the work space and console
+funcprot(0)
+
+// Given data
+V = 500.0 // Shunt motor voltage(V)
+load = 400.0 // Hoist load(kg)
+speed = 2.5 // Hoist raised speed(m/sec)
+n_motor = 0.85 // Efficiency of motor
+n_hoist = 0.75 // Efficiency of hoist
+
+// Calculations
+P_output = load*speed*9.81 // Power output from motor(W)
+P_input = P_output/(n_motor*n_hoist) // Motor input(W)
+I = P_input/V // Current drawn from supply(A)
+output_G = load*speed*9.81*n_motor*n_hoist // Generator output(W)
+R = V**2/output_G // Resistance required in the armature circuit for rheostatic braking(ohm)
+
+// Results
+disp("PART IV - EXAMPLE : 1.20 : SOLUTION :-")
+printf("\nCurrent drawn by the motor from supply = %.1f A", I)
+printf("\nResistance required in the armature circuit for rheostatic braking, R = %.f ohm", R)
diff --git a/3472/CH39/EX39.21/Example39_21.sce b/3472/CH39/EX39.21/Example39_21.sce new file mode 100644 index 000000000..e7b059c35 --- /dev/null +++ b/3472/CH39/EX39.21/Example39_21.sce @@ -0,0 +1,25 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.21 :
+// Page number 705
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+t = 1.0 // Time(hour)
+hp = 15.0 // Motor rating(hp)
+T = 2.0 // Time constant(hour)
+theta_f = 40.0 // Temperature rise(°C)
+
+// Calculations
+P = (1.0/(1-exp(-t/T)))**0.5*hp // One-hour rating of motor(hp)
+
+// Results
+disp("PART IV - EXAMPLE : 1.21 : SOLUTION :-")
+printf("\nOne-hour rating of motor, P = %.f hp\n", P)
+printf("\nNOTE: Changes in the obtained answer from that of textbook is due to more approximation in the textbook solution")
diff --git a/3472/CH39/EX39.22/Example39_22.sce b/3472/CH39/EX39.22/Example39_22.sce new file mode 100644 index 000000000..f31dd4298 --- /dev/null +++ b/3472/CH39/EX39.22/Example39_22.sce @@ -0,0 +1,34 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.22 :
+// Page number 706
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+hp = 10.0 // Motor rating(hp)
+d = 0.7 // Diameter of cylinder(m)
+l = 1.0 // Length of cylinder(m)
+w = 380.0 // Weight of motor(kgm)
+heat_specific = 700.0 // Specific heat(J/kg/1°C)
+heat_dissipation = 15.0 // Outer surface heat dissipation rate(W/sq.cm/°C)
+n = 0.88 // Efficiency
+
+// Calculations
+output = hp*735.5 // Output of motor(W)
+loss = (1-n)/n*output // Losses(W)
+area_cooling = %pi*d*l // Cooling surface area(sq.m)
+theta_m = loss/(area_cooling*heat_dissipation) // Final temperature rise(°C)
+T_sec = w*heat_specific/(area_cooling*heat_dissipation) // Thermal time constant(sec)
+T_hour = T_sec/3600 // Thermal time constant(hours)
+
+// Results
+disp("PART IV - EXAMPLE : 1.22 : SOLUTION :-")
+printf("\nFinal temperature rise, θ_m = %.1f°C", theta_m)
+printf("\nThermal time constant of the motor = %.2f hours\n", T_hour)
+printf("\nNOTE: ERROR: Mistake in calculating thermal time constant in the textbook solution")
diff --git a/3472/CH39/EX39.23/Example39_23.sce b/3472/CH39/EX39.23/Example39_23.sce new file mode 100644 index 000000000..5e3f721b6 --- /dev/null +++ b/3472/CH39/EX39.23/Example39_23.sce @@ -0,0 +1,31 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.23 :
+// Page number 706
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+hp = 25.0 // Motor rating(hp)
+T = 100.0/60 // Heating time constant(hour)
+theta = 40.0 // Temperature rise(°C)
+t = 0.5 // Time(hour)
+n = 0.85 // Motor maximum efficiency
+
+// Calculations
+output = hp*735.5/1000 // Output of motor(kW)
+output_max = output*n // Power at maximum efficiency(kW)
+theta_f2 = theta/(1-exp(-t/T)) // θ_f2(°C)
+loss = 1+(output/output_max)**2 // Losses at 18.4 kW output in terms of W
+P = ((theta_f2/theta*loss)-1)**0.5*output_max // Half-hour rating of motor(kW)
+P_hp = P*1000/735.5 // Half-hour rating of motor(hp)
+
+// Results
+disp("PART IV - EXAMPLE : 1.23 : SOLUTION :-")
+printf("\nHalf-hour rating of motor, P = %.f kW = %.1f hp (metric)\n", P,P_hp)
+printf("\nNOTE: ERROR: Calculation mistake from final temperature rise onwards in textbook")
diff --git a/3472/CH39/EX39.24/Example39_24.sce b/3472/CH39/EX39.24/Example39_24.sce new file mode 100644 index 000000000..089658642 --- /dev/null +++ b/3472/CH39/EX39.24/Example39_24.sce @@ -0,0 +1,26 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.24 :
+// Page number 706
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+theta_f1 = 40.0 // Temperature rise(°C)
+T = 100.0 // Heating time constant(min)
+rated_2 = 2.0 // Motor at twice the continuously rating
+
+// Calculations
+loss_cu = 2.0**2 // Copper loss at twice full load in terms of W
+loss_total = loss_cu+1 // Total losses at full load in terms of W
+theta_f2 = theta_f1*loss_total/rated_2 // θ_f2(°C)
+t = log(1-(theta_f1/theta_f2))*(-T) // Time for which motor can run at twice the continuously rated output without overheating(min)
+
+// Results
+disp("PART IV - EXAMPLE : 1.24 : SOLUTION :-")
+printf("\nMotor can run at twice the continuously rated output without overheating for time, t = %.f min", t)
diff --git a/3472/CH39/EX39.25/Example39_25.sce b/3472/CH39/EX39.25/Example39_25.sce new file mode 100644 index 000000000..9af102b6f --- /dev/null +++ b/3472/CH39/EX39.25/Example39_25.sce @@ -0,0 +1,30 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.25 :
+// Page number 706-707
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+kW = 20.0 // Motor output(kW)
+theta_1 = 50.0 // Temperature rise not to be exceeded on overload(°C)
+t_1 = 1.0 // Time on overload(hour)
+theta_2 = 30.0 // Temperature rise on full-load(°C)
+t_2 = 1.0 // Time on full-load(hour)
+theta_3 = 40.0 // Temperature rise on full-load(°C)
+t_3 = 2.0 // Time on full-load(hour)
+
+// Calculations
+e_lambda = 1.0/3 // Obtained directly from textbook
+theta_f = theta_2/(1-e_lambda) // θ_f(°C)
+theta_f1 = theta_1/(1-e_lambda) // θ'_f(°C)
+P = (theta_f1/theta_f)**0.5*kW // Maximum overload that can be carried by the motor(kW)
+
+// Results
+disp("PART IV - EXAMPLE : 1.25 : SOLUTION :-")
+printf("\nMaximum overload that can be carried by the motor, P = %.1f kW", P)
diff --git a/3472/CH39/EX39.26/Example39_26.sce b/3472/CH39/EX39.26/Example39_26.sce new file mode 100644 index 000000000..a61686a04 --- /dev/null +++ b/3472/CH39/EX39.26/Example39_26.sce @@ -0,0 +1,31 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.26 :
+// Page number 707-708
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+hp_1 = 100.0 // Motor load(hp)
+t_1 = 10.0 // Time of operation(min)
+hp_2 = 0 // Motor load(hp)
+t_2 = 5.0 // Time of operation(min)
+hp_3 = 60.0 // Motor load(hp)
+t_3 = 8.0 // Time of operation(min)
+hp_4 = 0 // Motor load(hp)
+t_4 = 4.0 // Time of operation(min)
+
+// Calculations
+t_total = t_1+t_2+t_3+t_4 // Total time of operation(min)
+rms = ((hp_1**2*t_1+hp_2**2*t_2+hp_3**2*t_3+hp_4**2*t_4)/t_total)**0.5 // rms horsepower
+
+// Results
+disp("PART IV - EXAMPLE : 1.26 : SOLUTION :-")
+printf("\nRequired size of continuously rated motor = %.f H.P\n", rms)
+printf("\nNOTE: ERROR: Calculation mistake in the textbook")
+printf("\n Actual value is written here instead of standard values")
diff --git a/3472/CH39/EX39.27/Example39_27.sce b/3472/CH39/EX39.27/Example39_27.sce new file mode 100644 index 000000000..999799459 --- /dev/null +++ b/3472/CH39/EX39.27/Example39_27.sce @@ -0,0 +1,29 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.27 :
+// Page number 708
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+hp_1 = 200.0 // Motor load(hp)
+t_1 = 5.0 // Time of operation(min)
+hp_2 = 100.0 // Motor load(hp)
+t_2 = 10.0 // Time of operation(min)
+hp_3 = 0 // Motor load(hp)
+t_3 = 3.0 // Time of operation(min)
+
+// Calculations
+m = hp_1/t_1 // Slope of uniform rise power
+t_total = t_1+t_2+t_3 // Total time of operation(min)
+ans = integrate('(m*x)**2','x', 0, t_1) // Integarted uniform area upto 5 min
+rms = ((ans+hp_2**2*t_2+hp_3**2*t_3)/t_total)**0.5 // rms horsepower
+
+// Results
+disp("PART IV - EXAMPLE : 1.27 : SOLUTION :-")
+printf("\nrms horsepower = %.1f HP. Therefore, a motor of %.f H.P should be selected", rms,rms+4)
diff --git a/3472/CH39/EX39.28/Example39_28.sce b/3472/CH39/EX39.28/Example39_28.sce new file mode 100644 index 000000000..8a20cc1f0 --- /dev/null +++ b/3472/CH39/EX39.28/Example39_28.sce @@ -0,0 +1,32 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.28 :
+// Page number 710
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+V = 440.0 // DC shunt motor voltage(V)
+hp = 50.0 // Motor rating(hp)
+N = 600.0 // Speed(rpm)
+I = 80.0 // Current at full-load(A)
+I_1 = 1.1 // Lower current limit in terms of full current
+I_2 = 1.5 // Upper current limit in terms of full current
+J = 20.0 // Moment of inertia(kg-m^2)
+
+// Calculations
+T = hp*746*60/(2*%pi*N) // Full load torque of motor(N-m)
+T_avg_start = (I_1+I_2)/2*T // Average starting torque(N-m)
+T_g = ((I_1+I_2)/2-1)*T // Torque available for acceleration(N-m)
+alpha = T_g/J // Angular acceleration(rad/sec^2)
+t = 2*%pi*N/(60*alpha) // Time taken to accelerate the motor(sec)
+
+// Results
+disp("PART IV - EXAMPLE : 1.28 : SOLUTION :-")
+printf("\nTime taken to accelerate the motor to rated speed against full load torque, t = %.2f sec\n", t)
+printf("\nNOTE: ERROR: Calculation mistake in the textbook solution")
diff --git a/3472/CH39/EX39.29/Example39_29.sce b/3472/CH39/EX39.29/Example39_29.sce new file mode 100644 index 000000000..520026cba --- /dev/null +++ b/3472/CH39/EX39.29/Example39_29.sce @@ -0,0 +1,27 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.29 :
+// Page number 710
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+hp = 50.0 // Motor rating(hp)
+N = 600.0 // Speed(rpm)
+energy = 276.0 // Stored energy(kg-m/hp)
+
+// Calculations
+g = 9.81
+T = hp*746*60/(2*%pi*N*g) // Full load torque of motor(kg-m)
+J = hp*energy*2*g/(2*%pi*N/60)**2 // Moment of inertia(kg-m^2)
+alpha = T*g/J // Angular acceleration(rad/sec^2)
+t = 2*%pi*N/(60*alpha) // Time taken to accelerate the motor to rated speed(sec)
+
+// Results
+disp("PART IV - EXAMPLE : 1.29 : SOLUTION :-")
+printf("\nTime taken to accelerate the motor to rated speed, t = %.2f sec", t)
diff --git a/3472/CH39/EX39.3/Example39_3.sce b/3472/CH39/EX39.3/Example39_3.sce new file mode 100644 index 000000000..7958fd845 --- /dev/null +++ b/3472/CH39/EX39.3/Example39_3.sce @@ -0,0 +1,31 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.3 :
+// Page number 680-681
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+V = 400.0 // IM voltage(V)
+s_fl = 5.0 // Full-load slip(%)
+I_fl = 20.0 // Full load current drawn from supply by IM(A)
+Z = 2.5 // Impedance per phase(ohm)
+I_max = 50.0 // Maximum current drawn(A)
+
+// Calculations
+V_phase = V/3**0.5 // Normal phase voltage(V)
+P = (100**2*I_max*Z/V_phase)**0.5 // Tapping to be provided to auto-transformer(%)
+I_s = I_max/(P/100) // Starting current taken by motor(A)
+T_s_fl = (I_s/I_fl)**2*s_fl/100 // Starting torque in terms of full-load torque
+T_s_fl_R = (I_max/I_fl)**2*s_fl/100 // Starting torque in terms of full-load torque when a resistor is used
+
+// Results
+disp("PART IV - EXAMPLE : 1.3 : SOLUTION :-")
+printf("\nTapping to be provided on an auto-transformer, P = %.1f percent", P)
+printf("\nStarting torque in terms of full-load torque, T_s = %.3f*T_fl ", T_s_fl)
+printf("\nStarting torque in terms of full-load torque if a resistor were used in series, T_s = %.4f*T_fl ", T_s_fl_R)
diff --git a/3472/CH39/EX39.30/Example39_30.sce b/3472/CH39/EX39.30/Example39_30.sce new file mode 100644 index 000000000..8c4fcffaa --- /dev/null +++ b/3472/CH39/EX39.30/Example39_30.sce @@ -0,0 +1,27 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.30 :
+// Page number 710
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+J = 1270.0 // Moment of inertia of fly-wheel(kg-m^2)
+N = 500.0 // Speed(rpm)
+hp = 50.0 // Motor rating(hp)
+
+// Calculations
+g = 9.81
+T = hp*746*60/(2*%pi*N*g) // Full load torque of motor(kg-m)
+T_m = 2*T // Accelerating torque(kg-m)
+alpha = T_m*g/J // Angular acceleration(rad/sec^2)
+t = 2*%pi*N/(60*alpha) // Time taken to accelerate a fly-wheel(sec)
+
+// Results
+disp("PART IV - EXAMPLE : 1.30 : SOLUTION :-")
+printf("\nTime taken to accelerate a fly-wheel, t = %.1f sec", t)
diff --git a/3472/CH39/EX39.31/Example39_31.sce b/3472/CH39/EX39.31/Example39_31.sce new file mode 100644 index 000000000..1b26cb7d0 --- /dev/null +++ b/3472/CH39/EX39.31/Example39_31.sce @@ -0,0 +1,34 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.31 :
+// Page number 710-711
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+N_1 = 1000.0 // Speed of dc shunt motor(rpm)
+N_2 = 400.0 // Speed of dc shunt motor(rpm)
+R = 14.0 // Resistance connected across armature(ohm)
+E_1 = 210.0 // EMF induced in armature at 1000 rpm(V)
+J = 17.0 // Moment of inertia(kg-m^2)
+T_F = 1.0 // Frictional torque(kg-m)
+
+// Calculations
+g = 9.81
+output = E_1**2/R // Motor output(W)
+T_E = output*60/(2*%pi*N_1*g) // Electric braking torque(kg-m)
+w_1 = 2*%pi*N_1/60 // ω_1(rad/sec)
+k = T_E/w_1
+t = J/(g*k)*log(N_1/N_2) // Time taken for dc shunt motor to fall in speed with constant excitation(sec)
+kw = T_E*N_2/N_1 // kω
+t_F = J/(g*k)*log((1+T_E)/(1+kw)) // Time for the same fall if frictional torque exists(sec)
+
+// Results
+disp("PART IV - EXAMPLE : 1.31 : SOLUTION :-")
+printf("\nTime taken for dc shunt motor to fall in speed with constant excitation, t = %.1f sec", t)
+printf("\nTime for the same fall if frictional torque exists, t = %.1f sec", t_F)
diff --git a/3472/CH39/EX39.32/Example39_32.sce b/3472/CH39/EX39.32/Example39_32.sce new file mode 100644 index 000000000..806eba506 --- /dev/null +++ b/3472/CH39/EX39.32/Example39_32.sce @@ -0,0 +1,42 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.32 :
+// Page number 711
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+V = 400.0 // Voltage of synchronous motor(V)
+p = 8.0 // Number of poles
+J = 630.0 // Moment of inertia(kg-m^2)
+T_E = 165.0 // Braking torque(kg-m)
+kw_1 = 690.0 // Electric braking torque(kg-m)
+T_F = 1.4 // Frictional torque(kg-m)
+f = 50.0 // Frequency(Hz). Assumed normal supply frequency
+
+// Calculations
+g = 9.81
+// Case(a) Plugging
+T_B = T_E+T_F // Torque(kg-m)
+beta = T_B*g/J // Retardation(rad/sec^2)
+N_s = 120*f/p // Synchronous speed(rad/sec)
+w = 2*%pi*N_s/60 // ω(rad/sec)
+t_a = integrate('-1.0/beta','w', w, 0) // Time taken to stop the motor(sec)
+n_a = integrate('-w/(2*%pi*beta)','w', w, 0) // Number of revolutions
+// Case(b) Rheostatic braking
+k = kw_1/w
+t_b = J/(g*k)*log((T_F+kw_1)/T_F) // Time taken to stop the motor(sec)
+n_b = 1.0/(2*%pi*k)*(J/(g*k)*(T_F+kw_1)*(1-exp(-k*g*t_b/J))-T_F*t_b) // Number of revolutions
+
+// Results
+disp("PART IV - EXAMPLE : 1.32 : SOLUTION :-")
+printf("\nCase(a): Time taken to come to standstill by plugging, t = %.1f sec", t_a)
+printf("\n Number of revolutions made to come to standstill by plugging, n = %.f revolutions", n_a)
+printf("\nCase(b): Time taken to come to standstill by rheostatic braking, t = %.1f sec", t_b)
+printf("\n Number of revolutions made to come to standstill by rheostatic braking, n = %.f revolutions\n", n_b)
+printf("\nNOTE: ERROR: Calculation mistake in finding number of revolution in case(a) in textbook solution")
diff --git a/3472/CH39/EX39.33/Example39_33.sce b/3472/CH39/EX39.33/Example39_33.sce new file mode 100644 index 000000000..52a207005 --- /dev/null +++ b/3472/CH39/EX39.33/Example39_33.sce @@ -0,0 +1,32 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.33 :
+// Page number 712-713
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+hp = 500.0 // Rating of IM(hp)
+N_nl = 40.0 // No-load speed(rpm)
+S_fl = 0.12 // Slip at full-load
+T_l = 41500.0 // Load torque(kg-m)
+t = 10.0 // Duration of each rolling period(sec)
+
+// Calculations
+g = 9.81
+T_fl = hp*746*60/(2*%pi*N_nl*g*(1-S_fl)) // Torque at full-load(kg-m)
+T_m = 2.0*T_fl // Motor torque at any instant(kg-m)
+slip = S_fl*N_nl // Slip(rpm)
+slip_rad = slip*2*%pi/60 // Slip(rad/sec)
+k = slip_rad/T_fl
+J = -g*t/(k*log(1-(T_m/T_l))) // Inertia of flywheel(kg-m^2)
+
+// Results
+disp("PART IV - EXAMPLE : 1.33 : SOLUTION :-")
+printf("\nInertia of flywheel required, J = %.3e kg-m^2\n", J)
+printf("\nNOTE: ERROR : J = 2.93*10^6 kg-m^2 and not 2.93*10^5 as mentioned in the textbook solution")
diff --git a/3472/CH39/EX39.34/Example39_34.sce b/3472/CH39/EX39.34/Example39_34.sce new file mode 100644 index 000000000..12d6c3b96 --- /dev/null +++ b/3472/CH39/EX39.34/Example39_34.sce @@ -0,0 +1,30 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.34 :
+// Page number 713
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+T_l = 150.0 // Load torque(kg-m)
+t = 15.0 // Duration of load torque(sec)
+T_m = 85.0 // Motor torque(kg-m)
+N = 500.0 // Speed(rpm)
+s_fl = 0.1 // Full-load slip
+
+// Calculations
+g = 9.81
+slip = N*s_fl*2*%pi/60 // Slip(rad/sec)
+k = slip/T_m
+T_0 = 0 // No-load torque(kg-m)
+J = -g*t/(k*log((T_l-T_m)/(T_l-T_0))) // Moment of inertia of flywheel(kg-m^2)
+
+// Results
+disp("PART IV - EXAMPLE : 1.34 : SOLUTION :-")
+printf("\nInertia of flywheel required, J = %.f kg-m^2\n", J)
+printf("\nNOTE: ERROR : Calculation mistake in the textbook solution")
diff --git a/3472/CH39/EX39.4/Example39_4.sce b/3472/CH39/EX39.4/Example39_4.sce new file mode 100644 index 000000000..51b88afe7 --- /dev/null +++ b/3472/CH39/EX39.4/Example39_4.sce @@ -0,0 +1,55 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.4 :
+// Page number 681-682
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+hp = 30.0 // Power of cage IM(hp)
+V = 500.0 // Cage IM voltage(V)
+P = 4.0 // Number of poles
+f = 50.0 // Frequency(Hz)
+I_fl = 33.0 // Full load current(A)
+s = 4.0/100 // Slip
+Z = 3.5 // Impedance per phase(ohm)
+tap = 60.0 // Auto-transformer tap setting(%)
+
+// Calculations
+// Case(1)
+I_s_1 = 3**0.5*(V/Z) // Starting current taken from line(A)
+N_s = 120*f/P // Speed(rpm)
+N_fl = N_s-N_s*s // Full load speed of motor(rpm)
+T_fl = hp*746*60/(2*%pi*N_fl) // Full load torque(N-m)
+T_s_1 = (I_s_1/I_fl)**2*s*T_fl // Starting torque(N-m)
+// Case(2)
+V_ph = V/3**0.5 // Phase voltage in star(V)
+I_s_2 = V_ph/Z // Starting current(A/phase)
+T_s_2 = (I_s_2/(I_fl/3**0.5))**2*s*T_fl // Starting torque(N-m)
+// Case(3)
+V_ph_at = V*tap/(3**0.5*100) // Phase voltage of auto-transformer secondary(V)
+V_impressed = V_ph_at*3**0.5 // Volatage impressed on delta-connected stator(V)
+I_s_3 = V_impressed/Z // Starting current(A/phase)
+I_s_line = 3**0.5*I_s_3 // Motor starting line current from auto-transformer secondary(A)
+I_s_line_3 = tap/100*I_s_line // Starting current taken from supply(A)
+T_s_3 = (I_s_3/(I_fl/3**0.5))**2*s*T_fl // Starting torque(N-m)
+// Case(4)
+I_s_4 = 3**0.5*V/Z // Starting current from line(A)
+T_s_4 = T_fl*s*(I_s_4/I_fl)**2 // Starting torque(N-m)
+
+// Results
+disp("PART IV - EXAMPLE : 1.4 : SOLUTION :-")
+printf("\nCase(1): Starting torque for direct switching, T_s = %.f N-m", T_s_1)
+printf("\n Starting current taken from supply line for direct switching, I_s = %.f A", I_s_1)
+printf("\nCase(2): Starting torque for star-delta starting, T_s = %.f N-m", T_s_2)
+printf("\n Starting current taken from supply line for star-delta starting, I_s = %.1f A per phase", I_s_2)
+printf("\nCase(3): Starting torque for auto-transformer starting, T_s = %.f N-m", T_s_3)
+printf("\n Starting current taken from supply line for auto-transformer starting, I_s = %.f A", I_s_line_3)
+printf("\nCase(4): Starting torque for series-parallel switch, T_s = %.f N-m", T_s_4)
+printf("\n Starting current taken from supply line for series-parallel switch, I_s = %.f A\n", I_s_4)
+printf("\nNOTE: ERROR: Calculation mistakes and more approximation in textbook solution")
diff --git a/3472/CH39/EX39.5/Example39_5.sce b/3472/CH39/EX39.5/Example39_5.sce new file mode 100644 index 000000000..5fc531d9c --- /dev/null +++ b/3472/CH39/EX39.5/Example39_5.sce @@ -0,0 +1,35 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.5 :
+// Page number 682
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+V = 400.0 // IM voltage(V)
+f = 50.0 // Frequency(Hz)
+I_s = 5.0 // Full voltage starting current in terms of full load current
+T_s = 2.0 // Full voltage starting torque in terms of full load torque
+tap = 65.0 // Auto-tranformer tapping(%)
+
+// Calculations
+V_ph = V/3**0.5 // Phase voltage(V)
+V_ph_motor = tap/100*V_ph // Motor phase voltage when auto-transformer is used(V)
+I_ph_motor = tap/100*I_s // Motor phase current in terms of full load current
+I_1 = tap/100*I_ph_motor // Line current from supply in terms of full load current
+T = (tap/100)**2*T_s // Starting torque in terms of full load current
+V_applied = V_ph/2**0.5 // Voltage to be applied to develop full-load torque(V)
+I_line = V_applied/V_ph*I_s // Line current in terms of full load current
+
+// Results
+disp("PART IV - EXAMPLE : 1.5 : SOLUTION :-")
+printf("\nCase(i): Motor current per phase = %.2f*I_fl ", I_ph_motor)
+printf("\nCase(ii): Current from the supply, I_1 = %.2f*I_fl ", I_1)
+printf("\nCase(iii): Starting torque with auto-transformer starter, T = %.3f*T_fl ", T)
+printf("\nVoltage to be applied if motor has to develop full-load torque at starting, V = %.f V", V_applied)
+printf("\nLine current from the supply to develop full-load torque at starting = %.2f*I_fl ", I_line)
diff --git a/3472/CH39/EX39.6/Example39_6.sce b/3472/CH39/EX39.6/Example39_6.sce new file mode 100644 index 000000000..8213ac133 --- /dev/null +++ b/3472/CH39/EX39.6/Example39_6.sce @@ -0,0 +1,30 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.6 :
+// Page number 682
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+hp = 10.0 // IM rating(hp)
+V = 400.0 // IM voltage(V)
+pf = 0.8 // Lagging power factor
+n = 0.9 // Efficiency of IM
+I_sc = 7.2 // Short-circuit current at 160V(A)
+V_sc = 160.0 // Voltage at short-circuit(V)
+
+// Calculations
+I_fl = hp*746/(3**0.5*V*pf*n) // Full-load line current(A)
+I_sc_fv = V/V_sc*I_sc // Short-circuit current at full voltage(A)
+I_s = I_sc_fv/3.0 // Starting current with star-delta starter(A)
+I_s_fl = I_s/I_fl // Ratio of starting current to full load current
+
+// Results
+disp("PART IV - EXAMPLE : 1.6 : SOLUTION :-")
+printf("\nRatio of starting current to full-load current, I_s/I_fl = %.1f \n", I_s_fl)
+printf("\nNOTE: ERROR: Calculation mistake in final answer in textbook solution")
diff --git a/3472/CH39/EX39.7/Example39_7.sce b/3472/CH39/EX39.7/Example39_7.sce new file mode 100644 index 000000000..19310d3b9 --- /dev/null +++ b/3472/CH39/EX39.7/Example39_7.sce @@ -0,0 +1,30 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.7 :
+// Page number 685-686
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+V = 230.0 // Voltage of DC shunt motor(V)
+N_1 = 1000.0 // No load speed(rpm)
+R_sh = 40.0 // Shunt resistance(ohm)
+N_2 = 1200.0 // Speed with series resistance(rpm)
+
+// Calculations
+phi_2 = N_1/N_2 // Flux_2 in terms flux_1
+I_N1 = V/R_sh // Exciting current at 1000 rpm(A)
+phi_1 = 11.9 // Flux corresponding to I_N1(mWb)
+phi_N2 = phi_1*phi_2 // Flux at 1200 rpm(mWb)
+I_phi_N2 = 3.25 // Exciting current corresponding to phi_N2(A)
+R = V/I_phi_N2 // Resistance in field circuit(ohm)
+R_extra = R-R_sh // Resistance to be placed in series with shunt field(ohm)
+
+// Results
+disp("PART IV - EXAMPLE : 1.7 : SOLUTION :-")
+printf("\nResistance to be placed in series with shunt field = %.1f ohm", R_extra)
diff --git a/3472/CH39/EX39.9/Example39_9.sce b/3472/CH39/EX39.9/Example39_9.sce new file mode 100644 index 000000000..b86bfc686 --- /dev/null +++ b/3472/CH39/EX39.9/Example39_9.sce @@ -0,0 +1,24 @@ +// A Texbook on POWER SYSTEM ENGINEERING
+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
+// DHANPAT RAI & Co.
+// SECOND EDITION
+
+// PART IV : UTILIZATION AND TRACTION
+// CHAPTER 1: INDUSTRIAL APPLICATIONS OF ELECTRIC MOTORS
+
+// EXAMPLE : 1.9 :
+// Page number 686-687
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+I_f1 = 25.0 // Current without diverter(A)
+N_1 = 500.0 // Speed of dc series motor without diverter(rpm)
+
+// Calculations
+I_a2 = ((3.0/2)**0.5*I_f1**2*3/2)**0.5 // Field current with diverter(A)
+N_2 = I_f1*N_1*3/(2*I_a2) // Speed with diverter(rpm)
+
+// Results
+disp("PART IV - EXAMPLE : 1.9 : SOLUTION :-")
+printf("\nSpeed when field winding is shunted by a diverter, N_2 = %.f rpm", N_2)
+printf("\nCurrent when field winding is shunted by a diverter, I_a2 = %.1f A", I_a2)
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