From b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b Mon Sep 17 00:00:00 2001 From: priyanka Date: Wed, 24 Jun 2015 15:03:17 +0530 Subject: initial commit / add all books --- 1938/CH2/EX2.15/2_15.jpg | Bin 0 -> 46291 bytes 1938/CH2/EX2.15/2_15.sce | 30 ++++++++++++++++++++++++++++++ 2 files changed, 30 insertions(+) create mode 100755 1938/CH2/EX2.15/2_15.jpg create mode 100755 1938/CH2/EX2.15/2_15.sce (limited to '1938/CH2/EX2.15') diff --git a/1938/CH2/EX2.15/2_15.jpg b/1938/CH2/EX2.15/2_15.jpg new file mode 100755 index 000000000..6da36eb26 Binary files /dev/null and b/1938/CH2/EX2.15/2_15.jpg differ diff --git a/1938/CH2/EX2.15/2_15.sce b/1938/CH2/EX2.15/2_15.sce new file mode 100755 index 000000000..18ec4e810 --- /dev/null +++ b/1938/CH2/EX2.15/2_15.sce @@ -0,0 +1,30 @@ +clc,clear +printf('Example 2.15\n\n') + +shaft_output = 80*746 //coverted to watts +eta= 80/100 //efficiency +V=250 +N_1=1200 +R_a=0.04,R_sh = 250 //armature and shunt field resistance +power_input = shaft_output/eta +I_L= power_input /V +I_sh= V / R_sh +I_a = I_L - I_sh +E_b1 = V - I_a*R_a + +gross_mechanical_power= E_b1*I_a //electrical equivalent of mechanical power developed +stray_losses = gross_mechanical_power - shaft_output +printf('Mechanical power developed on full load = %.3f kW\n',gross_mechanical_power/1000) + +//on no load shaft_output=0 and entire gross power is used to overcome stray losses +Eb0_Ia0= stray_losses +//E_b0 = V - I_a0*R_a ... solving for I_0 +p=[R_a -V Eb0_Ia0] +roots(p) +I_a0=ans(2) //first root is ignored since its too large +I_L0 =I_sh+I_a0 //current drawn from supply +E_b0 = V - I_a0*R_a + +//From speed equation N (prop.) E_b +N_0 = N_1*(E_b0/E_b1) +printf('No load speed and current are %.4f rpm and %.2f A respectively',N_0,I_L0) -- cgit