Figure 1 Connection Diagram for No - Load and Block Rotor Experiment
Related Figures (32)
It is possible to find the parameters of the equivalent circuit of the three phase induction motor experimentally as shown in Figure 3 below. ae" mae eit neat tli sinlitinliataititial ““ From these readings, the per phase values of the power P , and phase voltage V g, can be obtained as follows: Figure 4: Approximate Equivalent Circuit for the Locked Rotor Condition Then, Reg, equations: Zeq and X,q can be obtained using the following ae ae SS ——E— ————————E—E——EE——E—EEE_EEe oo Oe EE EE The computer simulation test carried out in this paper was done using Matlab/Simulink software, the induction motor tests using the Simulink program was implemented by designing models for the various tests. This part of the paper will consider the following simulations: Figure 6: Per-Phase Equivalent Circuit of an Induction Motor. http://www. ijetjournal.org 1.4.2.2. SIMULATION OF BLOCKED ROTOR TEST Rebemete = (RAVER RR BR BNI NR BPN BR BRN ENN BE The blocked rotor test (locked rotor test) was performed to determine the equivalent circuit parameters of an induction motor. This test corresponds to the short-circuit test on a transformer. In this test, the rotor is blocked so that it cannot move more than a voltage less than the rated voltage that was applied to the motor. The resulting current, voltage and power measurements enables us to compute the induction motor parameters. Figure 8, shows the Simulink diagram for the blocked rotor test. We used the same induction motor parameters as the no-load test. However, in order to simulate blocked rotor condition, we set the inertia of the rotor to infinite. In this test, the rotor is locked. A three-phase AC voltage was applied to the motor and adjusted to an appropriate value so that the current flow of each phase is equal to its rated value. Recall that the rated current is 2.6Amps, the simulation was run at various frequencies and data obtained on phase A current (Iq), phase A RMS voltage (V4) and phase A input real and reactive powers (Pa, Qa). 1.4.2.3. SIMULATION TEST FOR NO-LOAD The no-load test on the induction motor measures the rotational losses of the motor and it is able to evaluate its magnetizing current. In this test, a rated balanced AC voltage of 220Vrms per-phases with a rated frequency of 50Hz was applied to the stator and rotor runs without any load. The Simulink diagram of the no-load test is given in Figure 9. We also used the same induction motor for the DC test. The Y-connected 3-phase ideal voltage (phase A, phase B and _ phase C) source is connected to the stator windings. A zero mechanical load was applied to the rotor of the induction motor (input terminal Tm) to simulate the no-load condition. Some measurement blocks have been added to the diagram to measure some of the electrical and mechanical quantities, which are the Real and reactive power for the phase A (phase-A-power), the rms currents of the phases (abec_rms_currents), mechanical speed (mech-speed, Wm), electrical torque (elect-torque, Te) etc. Figure 9: Simulink Diagram for No-Load Test. The various tests for the machine for both the laboratory experiment and the simulation method were conducted and the data obtained are presented below. This simulation, a rated voltage was applied to the stator through a Y-connected AC voltage source. Recall that the per phase rms voltage is 220V. Therefore; we choose the peak amplitude as 310V for each AC voltage source. Figure 10 shows the Simulink diagram for the load test. The induction motor block has an input terminal labelled as Ti through this terminal different mechanical load were put to the shaft of the motor. The mechanical load Tm is specified in terms of torque (N.m). The simulations for various values of Tm were done and the mechanical speed, slip speed, output power, and motor efficiency changes with the load were also recorded. From the data obtained, the following calculations were made: Ontnut nower at each load level: P...§=T..w. 33 slip speed, output power, and motor efficiency changes with the load were also recorded. From the data obtained, the following calculations were made: Table 2: No Load Test Record The records obtained are recorded i in Table3 below; At each frequency Ryp and X,p are computed using the following formulas: Table 6: Simulation Record for Load Test From the data obtained, the following calculations were made and tabulated in Table 7 below: The three phase total input power: P3o = 3P, = 356.23 = 169W, the stator copper losses: Pscy = 3°AR, = 30W, the rotational losses: P,o¢ = 3P4- Psc, = 139W. Figure 11: Active and Reactive Power Waveform Output power at each load level: Pour = Tmwm , Total input power at each load level: Pij = 3P, , Efficiency of the motor at each load level: n% = Pour/Pin x 100, Slip at each load level: S = (1500 - ny )/1500, Speed at each load level: N,, = (W,,./22)x60 rpm. Table 7: Calculated Values from Measured Values for Load Test Simulation Figure 12: Mechanical Speed Waveform for Blocked Rotor Test Simulation. Figure 13: Electromagnetic Torque Waveform for Blocked Rotor Test Simulation. Figure 14: Active and Reactive Power Waveform for No Load Test Simulation. Figure 16: Electromagnetic Torque Waveform for No Load Test Simulation. Figure 15: Mechanical Speed Waveform for No-load Test Simulation. Figure 17: Current Waveform at for No Load Test Simulation. Figure 18: Mechanical Speed Waveform at Full Load Test Simulation. Figure 19: Active and Reactive Power Waveform at Full Load Test Simulation. Figure 20: Electromagnetic Torque at Full Load Test Simulation. Figure 22: Active and Reactive Power Waveform at Overload Simulation. Figure 21: Elecromagnetic Torque Waveform at Overload Simulation. Figure 23: Mechanical Speed Waveform at Overload Simulation. The following graphs were constructed to show the relationships between the various parameters obtained, as shown in the following figures 24, 25, 26, 27, 28, 29 and 30 below: (1). Tn vs S, (2). Tm vs , (3). Pour VS Tm, (4). Nm VS Pour (5). In eS) Pour (6). Tn VS Nin (7). In VS Nin
