The performance and power flow of three phase induction motor Objective: This test is performed to study the power flow and performance of the three-phase inductionmotor. Theory: for this test, the three-phase induction motor IM is full loaded (full load test), that's when the inputcurrent of the loaded three phase IM equals the rated input current given on its name plate. At the end of the full load test, many parameters which determines the performance of the induction motor is to be calculated. Experimental Procedure: 1- Connect the circuit as per Fig. 1. N 11 A IM > VLL1 > VLL2 A Supply 12 DCGen COUPLING Iload A Load Vload > Nr Tm Pout Meter for measuring IM speed, Fig. 1: Schematic diagram for load test on Three Phase Induction que and output mechnical power Switch-on 3 phase AC mains and start the motor at reduced applied voltage. 2- Increase the applied voltage, till its rated value. 3- Increase the load on the motor gradually using the variable resistive load until the input current ofthe three phase IM equals its rated current given on its name plate. In this case, the full load test is achieved. 4- Record the required readings at full load test in table (1). 5- Reduce the load on the motor and finally unload it completely. 6- Switch-off the supply to stop the motor. P1 P2 VLL Nr Tout Parameters (watt) (watt) (volt) (r.p.m) (mN.m) Measured 64 77.5 242 1351 654 values Calculations: Using tablel, equivalent circuit in figure 1, power flow diagram in figure 2 and the per phase values of resistances and reactance's of the three phase IM that are calculated in the previous tests, find the following parameters in the purpose of studying the performance and the power flow of the three phaseinduction motor: 1. Find the synchronous speed Ns, motor slip S and slip speed ns of the three phase IM given that themotor has four poles fixed at the stator. 2. Find the frequency of the rotor 3. Find the input power factor of the three-phase induction motor 4. Find 11, 10 and 12' using equivalent circuit in Figure 1 (use current divider for 10 and 12'). R1 jX1 R2' ° jX2' m lo lc Im Vph R2*((1-s)/s) Rc jXm Fig.1. Per phase equivalent circuit diagram of induction motor 5. Find stator copper losses Pstator-Cu 6. Find core losses Pcore 7. Find air gap power Pg

A 3-phase, 415 V, 50 Hz induction motor draws 5 times the rated current at rated voltage at starting. It is required to bring down the starting current from the supply to 2 times of the rated current using a 3-phase autotransformer. If the magnetizing impedance of the induction motor and no load current of the autotransformer is neglected, then the transformation ratio of the autotransformer is given by. (round off to two decimal places).

Three Phase Induction Mot... The relative speed of stator magnetic field with respect to rotor of a 30 induction motor with 4 pole, 50 Hz frequency. If the slip is 0.05.

The stator resistance of a 1-phase induction motor is 2.5 ohms  and its leakage reactance is 2.0 ohms. Onno-load, the motor takes 4 A at 96 V and at 0.25 lagging power factor. The no-load friction andwindage loss is negligible. Under the blocked-rotor condition, the input power is 130 W at 6 A and42 V. Obtain the equivalent circuit parameters.

A value of magnetizing current in a 3-phase induction motor * gives power factor smaller .. larger smaller. .poor large . better O large...poor O

Question A 3-phase, 415 V, 4-pole, 50 Hz induction motor draws 5 times the rated current at rated voltage at starting. It is required to bring down the starting current from the supply to 2 times of the rated current using a 3-phase autotransformer. If the magnetizing impedance of the induction motor and no-load current of the autotransformer is neglected, then the transformation ratio of the autotransformer is given by

Find the value:

Motor efficiency is ............... % ? Air gap power is .............. W ? Percentage slip is equal to ...........% ? Rotor copper loss is ............ W ?

6- In a stepper motor, how is the speed of rotation determined? a) By the current supplied to the motor. b) By the magnitude of the voltage applied. c) By the load applied to the motor. d) By the frequency of the waveforms used. 7- A transformer core is laminated to a) reduce hysteresis loss b) reduce eddy current losses c) reduce copper losses d) reduce all above losses 8- An induction motor with 580 r.p.m. speed at 60 Hz will have a) 8 poles b) 6 poles c) 4 poles d) 2 poles 9- If any two phases for an induction motor are interchanged a) the motor will run in reverse direction b) the motor will run at reduced speed c) the motor will not run d) the motor will burn 10- No-Load speed of which of the following motor will be highest? a) Shunt motor b) Series motor c) Short-Shunt compound motor d) Long-Shunt compound motor