ELEC 2602 Lab 3 (LVSIM) Report 101177900 (1)
.pdf
School
Carleton University**We aren't endorsed by this school
Course
ELEC 2602
Subject
Electrical Engineering
Date
Dec 19, 2024
Pages
12
Uploaded by deb90db
Name Ron Biswas Student Number 101177900 Lab Section L4 Date Lab Performed 17/03/2023 Date Lab Report Submitted 18/03/2023 ELEC 2602 Lab 3 Three-Phase Induction Machine (Using LVSIM) Winter2023 Template for Lab Report Part A: Induction Motor Operation Part A1: Three-Phase Induction Motor No-Load and Full-Load Operation 14)Motor no-load speed n= 1800 RPM Record the direction of rotation of the three-phase induction motor. Motor direction of rotation: Clockwise Counter-clockwise 15) Is the motor no-load speed nyou recorded in the previous step very close to the synchronous speed nSof the three-phase induction motor Yes No 16) Nominal motor speed n= 1715 RPM Nominal motor torque T= 1.132 N·m Nominal motor line current IL= 1.01 A 17) Are the measured nominal motor speed nand line current ILrecorded in the previous step approximately equal to the nominal motor speed 1685 RPMand line current 1.14 A ratings of the Four-Pole Squirrel Cage Induction motor? Yes No Part A2: Three-Phase Induction Motor Operation Characteristics 22) Observe the recorded data in Data Table DTA1. Does the three-phase induction motor line current ILincrease as the torque Tproduced by the motor increases?
Name Ron Biswas Student Number 101177900 Lab Section L4 Date Lab Performed 17/03/2023 Date Lab Report Submitted 18/03/2023 Yes No 23)Insert graph GA1 here. Motor breakdown torque TBreak= 2.938N·m Motor locked-rotor torque TLocked= = 2.32N·m Observe the graph GA1 you just plotted. Describe how the three-phase induction motor torque Tvaries as the motor speed ndecreases. ___________________________________________________________________________________ The induction motor's torque first rises with increasing motor speed until it approaches the breakdown torque, at which point it rapidly decreases to zero. 24) Insert graph GA2 here.
Name Ron Biswas Student Number 101177900 Lab Section L4 Date Lab Performed 17/03/2023 Date Lab Report Submitted 18/03/2023 Does the graph GA2 confirm that the three-phase induction motor draws a fairly constant amount of reactive power from the three-phase ac power source during most of the reactive power- versus mechanical power curve? Yes No What is the approximate value of the constant reactive power? Q =300VAR Observe the graph GA2. Briefly explain why it is not recommended to use a three- phase induction motor in applications requiring the motor to work at less than its nominal mechanical power. As reactive power is constantly continuous, the total efficiency will be decreased even when the motor is operating at nominal load because of the constant reactive power. Is the amount of motor reactive power Q higher than the amount of motor active power P when the three- phase induction motor operates without load? Yes No What does this indicate about three-phase induction motors operating without load? It uses extremely little active power when there is no load, but constantly uses reactive power. 25) Insert graph GA3 here.
Name Ron Biswas Student Number 101177900 Lab Section L4 Date Lab Performed 17/03/2023 Date Lab Report Submitted 18/03/2023 Is the power factor leading or lagging? Briefly explain your choice. Leading PF Lagging PF Observe the graph GA3 you just plotted. Describe how the three-phase induction motor power factor PF varies as the motor mechanical power PMincreases. ___________________________________________________________________________________ When mechanical power grows, the power factor rises until it reaches its maximum. 26) Insert graph GA4 here,. Observe the graph GA4 you just plotted. Describe how the three-phase induction motor line current ILvaries as the motor mechanical powerPMincreases.
Name Ron Biswas Student Number 101177900 Lab Section L4 Date Lab Performed 17/03/2023 Date Lab Report Submitted 18/03/2023 The motor line current will rise slowly as mechanical power increases at lower power levels, rising more quickly at higher power levels about 300–400 W. 27) Insert graph GA5 here. Observe the graph GA5 you just plotted. Describe how the three-phase induction motor efficiency ηvaries as the motor mechanical power PMincreases. As mechanical power increases, motor efficiency also rises, reaching its highest levels at 400W at 66% efficiency. Part A3: Three-Phase Induction Motor Direction of Rotation 28) Record the direction of rotation of the three-phase induction motor. Motor direction of rotation: Clockwise Counter-clockwise Is the motor direction of rotation you just recorded opposite to the motor direction of rotation you recorded in step 14? Yes No Part B: Asynchronous Generator Mode of Operation
Name Ron Biswas Student Number 101177900 Lab Section L4 Date Lab Performed 17/03/2023 Date Lab Report Submitted 18/03/2023 35) Does the three-phase induction machine active power Pmeasured in the Data Table DT2 indicate that active power flows from the three-phase induction machine to the three-phase ac power source? Explain. Yes No Explain. _____________________________________________________________________________________ The answer is that the values for power are being negative, which explains the direction of current in the system. It is proposed that active power P indicated that the power is being provided to the ac source. Does this confirm that the three-phase induction machine currently operates as an asynchronous generator? Yes No 36)Insert graph GA6 here. Why is the torque negative?
Name Ron Biswas Student Number 101177900 Lab Section L4 Date Lab Performed 17/03/2023 Date Lab Report Submitted 18/03/2023 Due to the rotor being subjected to an external force, which causes a negative torque, the speed will be higher than the synchronous speed value. Why is the torque limited to -3.0 N-m? In order to prevent overload and potential machine damage, it is constrained by the breakdown torque. At what speed does the torque value first reach its limit? Torque data first reaches limit at 1978.2 RPM to 3000 RPM Observe the graph GA6 you just plotted. Describe how the three-phase induction machine torque Tvaries as the machine speed nincreases, ignoring the region where the torque is limited. Beginning virtually at zero, it quickly decreases until -3.0 N-m at around 1978.2 RPM. 37) Insert graph GA7 here. Does the graph GA7 confirm that the three-phase induction machine absorbs a fairly constant amount of reactive power from the three-phase ac power source during most of the reactive power- versus speed curve? Yes No 38) Insert graph GA8 here.
Name Ron Biswas Student Number 101177900 Lab Section L4 Date Lab Performed 17/03/2023 Date Lab Report Submitted 18/03/2023 Is the power factor leading or lagging? Leading PF Lagging PF Briefly explain your choice. Due to the fact that the power factor typically has a negative value Observe the graph GA8 you just plotted. Describe how the three-phase induction motor power factor PF varies as the machine speed increases. The power factor first declines as speed increases, but eventually it starts to rise. Can you relate this result to the graph GA7? With the rise in speed, the power factor and real power are increasing in the negative direction IL(input I1), active power P, reactive power Qand power factor PFindicated in the Metering application. 43) Insert graph GA9 here.
Name Ron Biswas Student Number 101177900 Lab Section L4 Date Lab Performed 17/03/2023 Date Lab Report Submitted 18/03/2023 Is the machine mechanical power an input power or an output power? Input Power Output Power Explain why. An input is the machine's mechanical power. It draws power from the machine since it functions as a generator and the input is really negative. Observe the graph GA9 you just plotted. Describe how the three-phase induction machine line current ILvaries as the machine mechanical powerPMincreases. The line current increases with the increase in power 44) Insert graph GA10 here.
Name Ron Biswas Student Number 101177900 Lab Section L4 Date Lab Performed 17/03/2023 Date Lab Report Submitted 18/03/2023 Observe the graph GA10 you just plotted. Describe how the three-phase induction machine real power Pand reactive power Qvary as the machine mechanical powerPMincreases. Real power increases as machine mechanical power increases, whereas reactive power remains positive between 300 and 400 VAR. Does the three-phase induction machine absorb a fairly constant amount of reactive power from the three- phase ac power source during most of the reactive power- versus mechanical power curve? Yes No 45) Insert graph GA11 here.
Name Ron Biswas Student Number 101177900 Lab Section L4 Date Lab Performed 17/03/2023 Date Lab Report Submitted 18/03/2023 Observe the graph GA11 you just plotted. Describe how the three-phase induction machine power factor varies as the machine mechanical powerPMincreases. With a rise in mechanical power Pm, power factor descends towards negative values. Can you relate this result to the plots in GA10? Power factor and active power both grow greatly when machine power increases, but reactive power very somewhat. 48) Line voltage without ac power applied voltage = 0V 49)Does the line voltage VLmeasured in the previous step confirm that a three-phase induction machine cannot operate as an asynchronous generator when it is not connected to a three-phase ac power source? Yes No Questions. Q1 Describe what the slip of a three-phase squirrel-cage induction motor is and how it varies as the load torque applied to the motor increases. The slip is the differential between the motor speed that rotates the magnetic field and the rotor speed. When the load torque is applied, the slip will rise. Q2Explain what the synchronous speed of a motor is. Which two parameters the synchronous speed of motor? A motor's synchronous speed is the rate at which it generates a revolving magnetic field. Voltage frequency and number of poles are two factors that affect speed. Q3Describe what happens to the speed of a three-phase squirrel-cage induction motor as the torque produced by the motor increases.
Name Ron Biswas Student Number 101177900 Lab Section L4 Date Lab Performed 17/03/2023 Date Lab Report Submitted 18/03/2023 ______________________________________________________________________________________ The induction motor's speed rises with increasing torque until it reaches the breakdown torque value, at which point it rapidly decreases. Q4Briefly describe how the virtually constant reactive power requirement of a three-phase squirrel-cage induction motor affects the motor power factor and efficiency? The induction motor's very constant reactive power causes it to lose power factor when the machine is operating at its nominal load. This results in increased energy losses and a reduced machine efficiency while operating at nominal power. Q5If an induction motor is running normally with small slip, how would you stop the motor quickly using the plugging mode? What happens to the mechanical energy during braking in the plugging mode? Two leads of the stator must be switched in order to swiftly halt the motor. By doing that, the magnetic field that determined the direction of rotation would shift its polarity and become the opposite.