Operating Characteristics of DC-AC Generators and Motors - Assignment Example

1- Executive Summary: - In this assignment we became familiar with the D.C and A.C motors and Generators. Effects of increasing torques are investigated for different types of machines i.e. series motors, induction motors (capacitor start and cage rotor) and synchronous motors. Most importantly Investigation of both single phase and three phase motors and generators is carried out. In the first experiment, DC series generator is investigated for its output voltage and output current and we see that they are directly related (not linearly) up to 950 mA of output current at a constant speed of 1500 rev/min. Second experiment shows that with increasing torque speed decreases. While output power first increases with torque but after 0.55 Nm it decreases again. And in the end efficiency increases up to 0.25 Nm of torque then decreases until 0.35 Nm then increases again up to 0.45 Nm and finally decreases again after 0.55 Nm. Third experiment is about capacitor start induction motors. It is seen that for capacitor start induction motors it is seen that for capacitor start induction motors speed decrease gradually with increasing torque. Whereas there is rapid increase in output current after torque goes beyond 0.7 Nm. Power factor and torque are nearly linear in relation i.e. power factor improves with torque while efficiency of capacitor start induction motor decreased after Torque goes beyond 1Nm. Fourth experiment is investigation of cage rotor induction motors. For cage rotor induction motors, Decrease in speed is quite gradual and increase in current is quite slow for increasing torque. While Power factor of this motor decreases when torque goes beyond 1.1 Nm (in our case) which means that power does not remain steady for increasing torque. Finally the last two experiments are the investigation of synchronous motors. We see that output power and torque are directly related to each other. The relation is exactly linear. Input power is also directly related to increasing torque but the relation is not quite exactly linear. Power factor for synchronous motors remains a lot steadier than for other motors. Efficiency curve is also quite smooth which means that characteristics of synchronous motors are superior to other motors. 2- Aims and Objectives: - The purpose of this assignment is to enable students understand the working and performances of D.C A.C machines both single phase and three phase motors and generators. In this assignment we became familiar with the D.C and A.C motors and Generators. Effects of increasing torques are investigated for different types of machines i.e. series motors, induction motors (capacitor start and cage rotor) and synchronous motors. Further, investigation of power factor performance of these machines is also the main aim of this assignment. 3- Experiments: - 3.1 Experiment # 1 Title: - The object of this experiment is to investigate the relationship between the output voltage of a DC series generator and its output current, when driven at constant speed. Equipment Required: - Equipment Initial settings Test Bed Speed range 1800 rev/min, D.C. supply 110 V, Field rheostat to 0, Armature Rheostat to ∞, START/STOP/RUN switch to RUN. FH50 compound machine Test Machine DC generator FH50 compound machine Prime mover DC motor Instrumentation frame V2 DC voltmeter 15/75/150V set to 15 A2 DFC ammeter 1.5A range R1 resistive load 50Ώ rheostat set to ∞, 2000Ώrheostat set to ∞. Circuit diagram: - Procedure: - I placed the FGH50 mimic diagram over the machine access terminals of the Test bed. Then I mounted the Test Generator into the right hand machine position and the prime mover FH 50 into the left hand position. Then I connected the circuit as shown in the circuit schematic diagram. By decreasing the values of R1 I recorded the corresponding values of output voltage and output current. Voltmeter and Ammeter were used for this purpose. Results: - Output current (mA) Output voltage (V) Output current (mA) Output voltage (V) 0 1.5 600 8.7 50 1.6 650 9.5 100 1.8 700 10.5 150 2.2 750 11.4 200 2.8 800 12.2 250 3.4 850 13 300 3.9 900 13.2 350 4.7 950 13.2 400 5.4 1000 12.8 450 6.2 1100 12 500 7 1200 11.2 550 7.9 Relation between output voltage and output current: - Following graph shows the relationship between V and I at output terminals, Explanation of results: - The above graph shows that output voltage and current are directly related (not linearly) up to 950 mA of output current. The reason is the construction of this generator i.e. field windings and armature windings are in series and change in load current directly changes field current. An increase in field current induces more voltage and hence terminal voltage is increased. Conclusions: - While obtaining the above readings speed (rev/min) of the prime mover changed whenever load resistance (R1) was changed. The reason to the speed change is that whenever load is increased on a series generator more current is drawn from it. When more current drawn more flux is produced which increases the speed as the speed = k×φ×ω. 3.2- Experiment # 8 Title: - The object of this experiment is to investigate the relationships between the speed, power output and efficiency of a DC series motor and the torque produced by the motor. Equipment Required: - Equipment Initial settings Test Bed Speed range 1800 rev/min, D.C. supply 110 V, Field rheostat to 0, Armature Rheostat to ∞, START/STOP/RUN switch to RUN. FH50 compound machine Prime mover DC motor Instrumentation frame V2 DC voltmeter 15/75/150V set to 15 A2 DFC ammeter 1.5A range Circuit Diagram: - Procedure: - I placed the FGH50 mimic diagram over the machine access terminals of the Test bed. Then I mounted the Test Generator into the right hand machine position and the prime mover FH 50 into the left hand position. Then I connected the circuit as shown in the circuit schematic diagram. Then I started the motor by reducing the armature rheostat to zero. Motor supply was adjusted to 110V. Voltmeter and Ammeter were used for the purpose of measuring currents and voltages. Calculations were made as explained under: - Results: - Torque Nm Speed (rev/min) Voltage (v) Current (A) Input power (W) Output power (W) Efficiency (p.u) 0.05 2550 116 1.1 127.6 13.345 0.104585 0.1 2300 110 1.25 137.5 24.073333 0.175079 0.15 2150 110 1.35 148.5 33.755 0.227306 0.2 2000 110 1.45 159.5 41.866667 0.262487 0.25 1850 110 1.5 165 48.408333 0.293384 0.3 1700 110 1.7 187 53.38 0.285455 0.35 1500 110 1.85 203.5 54.95 0.270025 0.4 1400 110 1.95 214.5 58.613333 0.273256 0.45 1300 110 2.01 221.1 61.23 0.276934 0.5 1200 110 2.12 233.2 62.8 0.269297 0.55 1100 110 2.3 253 63.323333 0.25029 0.6 950 110 2.4 264 59.66 0.225985 0.65 850 110 2.5 275 57.828333 0.210285 0.7 750 110 2.6 286 54.95 0.192133 0.75 650 110 2.7 297 51.025 0.171801 Relationship of torque with speed, output power and efficiency, I - Torque and speed II - Torque and output power III- Torque and Current: - IV- Torque and efficiency: - Explanation of Results: - From the readings table and above graphs with increasing torque speed decreases. While output power first increases with torque but after 0.55 Nm it decreases again. And in the end efficiency increases up to 0.25 Nm of torque then decreases until 0.35 Nm then increases again up to 0.45 Nm and finally decreases again after 0.55 Nm. The reason is that armature current which is equal to load current is directly proportional to induced torque. When load on motor shaft is increased relative motion between rotor field and stator field is produced which induces more emf and more current is drawn. If more current is not available motor slows down. Conclusions: - The experiment shows that Torque-speed characteristics and efficiency-torque characteristics are not quite smooth. These get worse if torque increases beyond a certain limit. Reason is that when there is no relative motion no induced voltage is produced and torque is small. Small induced torque results in high speed. This is a disadvantage of this type of motor. 3.3- Experiment # 16 Title: - The object of this experiment is to investigate the relationships between the speeds, current, power factor and efficiency of a capacitor start induction motor and the torque produced by the motor. Equipment Required: - Equipment Initial settings Test Bed Speed range 1800 rev/min, D.C. supply 110 V, Field rheostat to 0, Armature Rheostat to ∞, START/STOP/RUN switch to RUN. FH80 capacitor motor Test machine Instrumentation frame V3 AC voltmeter 250V range A3 AC ammeter 3A range W1 AC Wattmeter 500 Watts C1Capacitive load Set to 15 mF Circuit Diagram: - Procedure: - I placed the FH80 mimic diagram over the machine access terminals of the Test bed. Then I mounted the FH80 Test Generator into the right hand machine position. Then I connected the circuit as shown in the circuit schematic diagram. Then I started the motor by reducing the armature rheostat to zero. Motor supply was adjusted to 110V. Voltmeter and Ammeter were used for the purpose of measuring currents and voltages. START/STOP/RUN button was set to RN before the Test and was set to STOP after the Test. Calculations were made as explained under: - Results: - Relationship of torque with speed, current, power factor and efficiency of a capacitor start induction motor. Following graphs show the these relationships, i- Torque and speed: - ii- Torque and Current: - iii- Torque and Power factor: - iv- Torque and efficiency: - Explanation of Results: - For capacitor start induction motors it is seen that speed decrease gradually with increasing torque. Whereas there is rapid increase in output current after torque goes beyond 0.7 Nm. Power factor and torque are nearly linear in relation i.e. power factor improves with torque while efficiency of capacitor start induction motor decreased after Torque goes beyond 1Nm. Reason is the inverse relation between the motors induced torque and speed. Which means: after full load is reached the motor slows down as there is no relative motion between rotor’s magnetic field and stator’s magnetic field. Hence induced voltage is zero. Zero induced voltage means no induced current in field which in turn reduces flux and speed decreases. Conclusions: - Capacitor start motors provide the advantage of starting torque when large loads are already installed to motor’s shaft and starting torque is required. 3.4- Experiment # 21 Title: - The object of this experiment is to investigate the relationships between the speed, current, output power, power factor and efficiency of a cage rotor induction motor and the torque developed by the motor. Equipment Required: - Equipment Initial settings Test Bed Speed range 1800 rev/min, D.C. supply 110 V, Field rheostat to 0, Armature Rheostat to ∞, START/STOP/RUN switch to RUN. FH90 capacitor motor Cage rotor induction motor Test Machine Instrumentation frame V3 AC voltmeter 250V range A3 AC ammeter 2A range W1 AC Wattmeter 500 Watts Circuit Diagram: - Procedure: - I placed the FH90 mimic diagram over the machine access terminals of the Test bed. Then I mounted the FH90 Test Generator into the right hand machine position. Then I connected the circuit as shown in the circuit schematic diagram. Then I pressed the green ON pushbutton to activate the contactor. Motor supply was adjusted to 110V. Voltmeter and Ammeter were used for the purpose of measuring currents and voltages. START/STOP/RUN button was set to RN before the Test and was set to STOP after the Test. Calculations were made as under: - Results: - Torque (Nm) Speed (rev/min) output power (w) wattmeter Wa(W) wattmeter Wb (w) Input Power (w) Line current (A) Line Voltage Volt amperes (VA) Power factor Efficiency (p.u) 0.1 1500 15.71 5 76 81 0.4 245 169.7 0.4773 0.19395 0.2 1500 31.41 8 82 90 0.4 245 169.7 0.5303 0.349 0.3 1480 46.49 18 90 108 0.4 245 169.7 0.6364 0.43046 0.4 1460 61.15 27 100 127 0.45 245 190 0.6684 0.4815 0.5 1450 75.9 38 110 148 0.45 245 190 0.7789 0.51284 0.6 1445 90.8 47 120 167 0.5 245 212.2 0.7871 0.54371 0.7 1420 104.1 58 130 188 0.55 245 233.4 0.8055 0.55372 0.8 1400 117.28 70 140 210 0.6 245 254.6 0.8248 0.55848 0.9 1380 130.06 80 150 230 0.65 245 275.8 0.8339 0.56548 1 1350 141.37 92 170 262 0.7 245 297 0.882 0.53958 1.1 1320 152.05 110 185 295 0.76 245 322.5 0.9147 0.51542 1.2 1280 160.85 120 210 330 0.85 245 360.7 0.9149 0.48742 1.3 1200 163.36 140 240 380 1 245 424.4 0.8955 0.42989 Relationship of torque with speed,output power, current, power factor and efficiency Following graphs show these relationships, i- Torque and speed: - ii- Torque and Output current: - iii- Torque and Output Power: - iv- Torque and Power Factor: - v- Torque and efficiency: - Explanation of Results: - Explanation to this section is the same as for capacitor start induction motor. Conclusions: - Explanation to this section is the same as for capacitor start induction motor. 3.5- Experiment # 25 Title: - The object of this experiment is to investigate the relationships between speed, input power, output power, current, power factor and efficiency of a synchronous motor and the torque produced by the motor. Equipment Required: - Equipment Initial settings Test Bed Speed range 1800 rev/min, D.C. supply 110 V, Field rheostat to 0, Armature Rheostat to ∞, START/STOP/RUN switch to RUN. FH100 slip ring machine Test Machine FH50 DC compound Machine Starting Motor Instrumentation frame V2 DC voltmeter 150 V range V3 AC voltmeter 250V range A3 AC ammeter 2A range W1 AC Wattmeter 500 Watts R1 resistive load 50Ώ set to ∞ and 2000Ώ set to 400 Ώ. Circuit Diagram: - Procedure: - I placed the FH100 mimic diagram over the machine access terminals of the Test bed. Then I mounted the slip ring machine into the right hand machine position and the prime mover FH50 into the left hand position. Then I connected the circuit as shown in the circuit schematic diagram. Voltmeter and Ammeter were used for the purpose of measuring currents and voltages while Watt meters were used for measuring powers. Calculations were made as under, Results: - Torque (Nm) Speed (rev/min) output power (w) Wattmeter Wa(w) wattmeter Wb (w) Input Power (w) Line current (A) Line Voltage Volt amperes (VA) Power factor Efficiency (p.u) 0.05 1500 7.85 30 28 58 0.1 245 42.39 1.3684 0.13534 0.1 1500 15.7 36 30 66 0.15 245 63.58 1.0381 0.23788 0.2 1500 31.4 45 40 85 0.2 245 84.77 1.0027 0.36941 0.3 1500 47.1 52 50 102 0.24 245 101.7 1.0027 0.46176 0.4 1500 62.8 60 60 120 0.26 245 110.2 1.0889 0.52333 0.5 1500 78.5 70 70 140 0.32 245 135.6 1.0322 0.56071 0.6 1500 94.2 80 85 165 0.38 245 161.1 1.0244 0.57091 0.7 1500 109.9 85 102 187 0.44 245 186.5 1.0027 0.5877 0.8 1500 125.6 90 128 218 0.5 245 211.9 1.0287 0.57615 Relationship of torque with speed, input power, output power, current, power factor and efficiency Following graphs show these relations, i- Torque and output power ii- Torque and input power iii- Torque and power factor iv- Torque and efficiency v- Torque and Line current: - Explanation of Results: - We see that output power and torque are directly related to each other. The relation is exactly linear. Input power is also directly related to increasing torque but the relation is not quite exactly linear. Power factor for synchronous motors remains a lot steadier than for other motors. Efficiency curve is also quite smooth. Conclusions: - We conclude that synchronous motors produce the most reliable results when we see the effects of increasing load torque on motors. Power factor remains steady and speed torque characteristics are excellent. 3.6- Experiment # 26 Title: - The object of this experiment is to investigate the relationships between the current driving a synchronous motor and the excitation voltage applied to the rotor, for a range of torque values. Equipment Required: - Equipment Initial settings Test Bed Speed range 1800 rev/min, D.C. supply 110 V, Field rheostat to 0, Armature Rheostat to ∞, START/STOP/RUN switch to RUN. FH100 slip ring machine Test Machine FH50 DC compound Machine Starting Motor Instrumentation frame V2 DC voltmeter 150 V range V3 AC voltmeter 250V range A3 AC ammeter 2A range R1 resistive load 50Ώ set to ∞ and 2000Ώ set to 400 Ώ. Circuit Diagram: - Procedure: - I placed the FH100 mimic diagram over the machine access terminals of the Test bed. Then I mounted the slip ring machine into the right hand machine position and the prime mover FH50 into the left hand position. Then I connected the circuit as shown in the circuit schematic diagram. After setting the torque to 0.1Nm Voltmeter and Ammeter were used for the purpose of measuring currents and voltages while Watt meters were used for measuring powers. The above steps were repeated for other values of torque i.e. 0.15, 0.20, 0.25, 0.30, 0.35 and 0.40 Results: - Excitation voltage(V) Line Curent Torque 0.1 Nm Torque=0.15 Nm Torque=0.2 Nm Torque=0.25 Nm Torque=0.3 Nm Torque=0.35Nm Torque=0.4Nm 120 0.23 0.24 0.25 0.26 0.28 0.29 0.32 110 0.2 0.21 0.23 0.24 0.26 0.28 100 0.18 0.2 0.21 0.23 0.24 0.27 90 0.16 0.18 0.19 0.22 0.24 80 0.15 0.16 0.18 0.21 70 0.13 0.15 0.18 60 0.13 0.15 50 0.13 40 30 Relationship of torque with current driving a synchronous motor and the excitation voltage applied to the rotor: - Following graph shows the relation between current and excitation voltage for torque 0.1 Nm. All these graphs are also plotted in different figures as under: - Relation between current and excitation voltage for torque 0.15 Nm Relation between current and excitation voltage for torque 0.3 Nm Explanation of Results: - Excitation Voltage and current relation means that the motor draws more current when load torque is increased. Conclusions: - Increasing load torque causes the motor to draw more current in order to maintain constant speed. 4- Discussions and conclusions: - In this assignment we became familiar with the D.C and A.C motors and Generators. Effects of increasing torques are investigated for different types of machines i.e. series motors, induction motors (capacitor start and cage rotor) and synchronous motors. Further, investigation of power factor performance of these machines is also the main aim of this assignment. It can be concluded from the above experiments that synchronous motor produces best results if its power factor and efficiency characteristics are considered. We see that output power and torque are directly related to each other. The relation is exactly linear. Input power is also directly related to increasing torque but the relation is not quite exactly linear. Power factor for synchronous motors remains a lot steadier than for other motors. Efficiency curve is also quite smooth which means that characteristics of synchronous motors are superior to other motors. 5- Equipment Specifications: - a- Test Bed: - The Test Bed (FH2) holds and gives power for most of the machines, except the Stepper Motor (FH150). This machine needs the Stepper Motor System (SMS2) to drive it. Integral eddy current dynamometer, with variable power supply and speed/torque displays internal D.C. and single-phase/three-phase power supplies, all fully protected. All power rated electrical circuits accessed at 4mm shrouded safety sockets with safety leads provided Compatible with comprehensive selection of electrical machines including hybrid stepper motor Facilities for monitoring and control by external instruments, e.g. analogue/digital computers Rugged steel construction Minimal installation and commissioning Supplied with comprehensive operating/experimental manual b- FH50 compound machine: - Works as a shunt, series and compound motor and also works as a generator. Approximate ratings are: As a motor: 100 W (shunt), 110 V, 1500 rev.min–1 As a generator: 40 W (shunt), 110 V, 1500 rev.min–1 Note: For d.c. generator experiments, two FH50s are needed – one as the test machine itself and the other as the prime mover. c- Capacitor Motor (FH80): Single-phase capacitor start/run induction motor Four-pole, 180 W, 230 V, 50/60 Hz Nominal speed: 1490/1780 rev.min–1 Note: To complete all experiments with this motor in the FH2/3 user guide requires three Capacitance Load Modules (C1). d- Cage Rotor Induction Motor (FH90): Three-phase, four-pole induction motor 120 W, 230 V (Delta), 50/60 Hz Nominal speed: 1473/1770 rev.min–1 Star or delta operation e- Synchronous motor: 120 W, 230 V (Delta), 50/60 Hz, three-phase Synchronous speed: 1500/1800 rev.min–1 • Synchronous generator: 80 W, 230 V (Delta), 50/60 Hz, three-phase Synchronous speed: 1500/1800 rev.min–1 Note: FH50 required as prime mover 6- References [1]- Electric Power Systems, 4th Edn., B.M WEEDY AND B.J. CORY, 2001, JOHN WILEY & SONS LTD [2]- Power Systems - Design and Analysis, 4th Edn., J. DUNCAN GLOVER, MULUKUTLA S. SARMA, THOMAS J. VERBYE. [3]- http://www.tecquipment.com/Datasheets/FH%20Machines_0808.pdf [4]- FH2/3 Electric Machines teaching systems students guide. 7- Appendix M-Files for the graphs drawn above are as: - Experiment 8: - Relation between torque and efficiency. t=[0.05,0.1,0.15,0.2,0.25,0.3,0.35,0.4,0.45,0.5,0.55,0.6,0.65,0.7,0.75] e=[0.104584639,0.175078788,0.227306397,0.262486938,0.293383838,0.285454545,0.27002457,0.273255633,0.276933514,0.269296741,0.250289855,0.225984848,0.210284848,0.192132867,0.171801347] figure(1) plot(t,e,r,linewidth,5) set(gca,fontsize,14) xlabel(Torque (Nm)) ylabel(Efficiency (p.u)) title(Relation between Torque and Efficiency) axis([-0.5,1,0.1,0.3]) Experiment 16: - Relation between torque and speed. t=[0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1,1.1,1.2,1.3] s=[1500,1500,1490,1460,1450,1450,1450,1440,1430,1400,1390,1375,1350] figure(1) plot(t,s,r,linewidth,5) set(gca,fontsize,14) xlabel(Torque (Nm)) ylabel(Speed rev/min) title(Relation between Torque and Speed) axis([-0.01,2,1200,1600]) grid on Experiment 16: - Relation between torque and Power Factor. t=[0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1,1.1,1.2,1.3] i=[0.470006184,0.488818282,0.534499514,0.552220888,0.600240096,0.636254502,0.67072443,0.69547372,0.744165069,0.762620838,0.805860806,0.816326531,0.85260771] figure(1) plot(t,i,r,linewidth,5) set(gca,fontsize,14) xlabel(Torque (Nm)) ylabel(Power Factor) title(Relation between Torque and Power Factor) axis([-0.01,2,0.3,1]) grid on Experiment 16: - Relation between torque and Efficiency. t=[0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1,1.1,1.2,1.3] i=[0.0826842,0.15705,0.2127727,0.2658696,0.30368,0.3437736,0.3782562,0.3955082,0.4083939,0.4129859,0.4158701,0.411381,0.3910213] figure(1) plot(t,i,r,linewidth,5) set(gca,fontsize,14) xlabel(Torque (Nm)) ylabel(Efficiency (p.u)) title(Relation between Torque and Efficiency) axis([-0.01,2,0.05,0.5]) grid on Experiment # 21 Relation between torque and line current. t=[0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1,1.1,1.2,1.3,] i=[0.4,0.4,0.4,0.45,0.45,0.5,0.55,0.6,0.65,0.7,0.76,0.85,1] figure(1) plot(t,i,r,linewidth,5) set(gca,fontsize,14) xlabel(Torque (Nm)) ylabel(Line Current (A)) title(Relation between Torque and Line current) axis([0,1.5,0.2,2]) grid on Experiment # 21 Relation between torque and Efficiency. t=[0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1,1.1,1.2,1.3,] i=[0.19395,0.349,0.43046,0.4815,0.51284,0.54371,0.55372,0.55848,0.56548,0.53958,0.51542,0.48742,0.42989] figure(1) plot(t,i,r,linewidth,5) set(gca,fontsize,14) xlabel(Torque (Nm)) ylabel(Efficiency (p.u)) title(Relation between Torque and Efficiency) axis([0,1.5,0.1,0.7]) grid on Experiment # 21 Relation between torque and Power factor. t=[0.05,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,] i=[1.368408635,1.038103103,1.002713224,1.002713224,1.088919338,1.032204789,1.024443851,1.002713224,1.028665802] figure(1) plot(t,i,r,linewidth,5) set(gca,fontsize,14) xlabel(Torque (Nm)) ylabel(Power Factor) title(Relation between Torque and Power Factor) axis([0,1,0.5,1.5]) grid on Experiment # 25 Relation between torque and Power factor. t=[0.05,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8] i=[0.135344828,0.237878788,0.369411765,0.461764706,0.523333333,0.560714286,0.570909091,0.587700535,0.576146789] figure(1) plot(t,i,r,linewidth,5) set(gca,fontsize,14) xlabel(Torque (Nm)) ylabel(Power Factor) title(Relation between Torque and Power Factor) axis([0,1,0,0.7]) grid on Experiment # 25 Relation between torque and line current. e=[120,110,100,90,80,70,60,50] i=[0.23,0.2,0.18,0.16,0.15,0.13,0.13,0.13] figure(1) plot(e,i,r,linewidth,5) set(gca,fontsize,14) xlabel(Excitation Voltage (V)) ylabel(Current (A)) title(Relation between Torque and Current’) axis([40,130,0.1,0.3]) grid on Experiment # 26 t=[120,110,100,90,80,70,60,50] %specify the values obtained for torque e=[0.23,0.2,0.18,0.16,0.15,0.13,0.13,0.13] %specify the values of efficiency calculated %apply grid to graph r=[120,110,100,90,80,70,60] %specify the values obtained for torque h=[0.24,0.21,0.2,0.18,0.16,0.15,0.15] %specify the values of efficiency calculated %draw figure a=[120,110,100,90,80,70] b=[0.24,0.21,0.2,0.18,0.16,0.15] c=[120,110,100,90,] d=[0.24,0.21,0.2,0.18,] plot(t,e,r,h,a,b,c,d,linewidth,5) legend(0.1Nm,0.15Nm,0.2Nm,0.3Nm) %plots the efficiency against torque with line width of 5 set(gca,fontsize,14) %font size of labeling is set to 15 on current axis xlabel(Current (A)) %specify independent varialble ylabel(Excitation Voltage) %specify dependent variable title(Relation between Current and Excitation Voltage) %give title axis([50,150,0.1,0.3]) %apply grid to graph Read More