Load test on 3 phase induction motor direct method youtube. Induction machines are considered relatively reliable and robust due to their simple design and welldeveloped manufacturing technology. The most common type of ac motor being used throughout the work today is the induction motor. Pdf on aug 22, 2016, mallikarjun hudedmani and others published noload and load tests on 3 phase induction motors used in irrigation. The open circuit test performed on the transformer. The set up for no load test of induction motor is shown in the figure. The friction and windage losses are 600 w, the core losses are 1800 w, and the stray losses are negligible. The basic idea of an electric motor is to generate two magnetic fields. Geared motors and pump motors are often standard motors equipped with. The three phase induction motor has been the induction motor can be calculated from the no load test, workhorse for industrial and manufacturing processes 2. Since the power factor of the induction motor under a no load condition is generally less than 0. There are two basic reasons for the use of single phase motors rather than 3 phase motors.
At full load, the motor runs at n rpm rotor speed decreases slightly from synchronous speed with increasing load torque motor will stall when the load torque exceeds the breakdown torque. The synchronous speed of an induction motor depends on the frequency. They are used in situations where large power is required. Induction motor theory quiz electrician practice tests. When a three phase induction motor connected to a single phase power supply using the steinmetz connection operates in a practical no load condition, not all windings consume active power. How to test three phase ac motors learning electrical. Uses same test instrument setup as lockedrotor test. Load test on three phase induction motor experiment. As the name suggest no load test is performed when rotor rotates with synchronous speed and there is no load torque. It supplies an induction motor ich has a full load speed of 144wh 0 rpm. If the wrong polarity motor is supplied with three phase supply, the magnetic field distribution within the motor windings become uneven and the output torque becomes pulsating.
Circuit diagram for no load test on a 3 phase induction motor. No load test is same as the open circuit test performed on the transformer. Free online electrician practice test questions on induction motor theory quiz leave a reply cancel reply. No load test frequency 60 hz linetoline voltage 2200 v line current 4. Two digital multimeters and fluke power quality meter. Load test on three phase induction motor theory uncategorized april 15, 2020 0 abdul gofur pdf three phase induction motor tests squirrel cage induction motor load test on three phase induction motor no load test of an induction motor. The stator circuit model of an induction motor consists of a stator phase winding resistance r 1, stator phase winding leakage reactance x 1 as shown in the circuit diagram below the no load current i 0 is simulated by a pure inductive reactor x 0. They are found everywhere from a small workshop to a large manufacturing industry. Testing and commissioning procedure for electric motors eep. The machine is started in the usual way and runs unloaded from normal voltage mains. Pdf a comparative analysis of three phase induction motor. Load tests on a three phase induction motor and measurement of the inrush current objectives. To this end, it will be assumed that the motor is a balanced three phase wye connected load and that you will therefore need to measure only one lineneutral voltage, only one line current, and only one phase power to characterize p in completely.
Under normal running conditions the rotor ironlosses are negligibly small. Load test on 3 phase induction motor load test on three phase induction motor direct method load test on 3 phase squirrel cage induction. Apply rated voltage and frequency with no mechanical load. A three phase, 12 pole, salient pole alternator is coupled to a diesel engine running at 500 rpm. Following data is taken from no load, locked rotor, and dc tests of a 3 phase, wye connected 40 hp, 60 hz, 460 v, induction motor with a rated current of 57. The purpose of the no load test is t o quantify the no. The no load test of 3 phase induction motor is performed on induction motor when it is running without load. Actually, to achieve synchronous speed in an induction motor is impossible. Pdf noload and load tests on 3 phase induction motors used in. The test is performed by applying balanced rated voltage on the stator. Approximate equivalent circuit of an induction motor.
No load test of induction motor your electrical guide. The 3 phase set of currents, each of equal magnitude and with a phase. In an induction motor, the change in slip from no load to full load is hardly 0. This test tells us the magnitude of constant losses occurring in the motor. Here in this experiment we perform load test on 3 phase induction motor to study the different performance characteristics of 3 phase im. Circuit diagram for no load and blockedrotor test on 3 phase induction motor a. We have run the motor for 4hr and every 30 min current has measured. To conduct the load test on 3phase induction motor.
Induction motor is one of the most important motor used in industrial applications. To measure the inrush current when the motor starts. The induction motor rotor is a completely shortcircuited conductive cage. A 3 phase induction motor can be used for different applications with various speed and load requirements. Induction motor, no load test, blocked rotor test, vibration test, temperature test, phase sequence test, insulation resistance test. A 480v, 60 hz, 6pole, three phase, deltaconnected induction motor has the. Therefore, it is, necessary to reverse the direction of currentcoil terminals to take the reading. Disconnect any mechanical load connected to the induction motor. Information guide for general purpose industrial ac small.
To determine the equivalent circuit parameters of an induction motor. A 480v, 60 hz, 50hp, three phase induction motor is drawing 60 a at 0. Single phase induction motors are used extensively for smaller loads, such as household appliances like fans. Power supply test for three phase motors, the expected voltage for a 230400v system is 230v phase to neutral and 400v between each of the three phase supply lines. Find the percentage slip and number of poles of the induction motor. The issue of sealing elements is also partially dealt with in iec 6003430. Gradually apply three phase voltage across motor stator terminals via the autotransformer d. Induction machines 18 the no load condition is that which obtains when the controller knob is fully counterclockwise. An induction motors rotor can be either wound type or squirrelcage type. For reason of economy, most houses, offices and also rural areas are supplied with single phase a. Check that the correct voltage is applied to the motor using a multimeter.
Ensure motor is unloaded and the variac is set at zero position. Noload and blocked rotor test on an induction machine. Ensure the terminal for power supply is in good condition. The three phase squirrelcage induction motor can, and many times does, have the same armature stator winding as the three phase synchronous motor. Thus no load and blocked rotor tests are performed on the motors. You can then quantify the motor s part load by comparing the measured input power under. To obtain the load performance characteristics of a threephase squirrelcage induction motor. Note down the machine ratings and calculate rated current of the machine no load test. April 11, 20 1 of 10 experiment induction motor three phase induction motors 208v ll objective this experiment demonstrates the performance of squirrelcage induction motors and the method for deriving electrical equivalent circuits from test data. This paper aims to represent routine test performing in three phase induction motor. This test is similar to the open circuit test on transformer. How to test a 3 phase motor windings with an ohmmeter. As in the synchronous motor, applying three phase currents to the armature creates a synchronously rotating magnetic field. A single phase induction motor with main winding arranged for direct connection to power source and auxiliary winding connected in series with a capacitor.
The rotor will constantly be turning to align its magnetic field with that of the stator field. Three phase squirrelcage induction motors are widely used as industrial drives because they are selfstarting, reliable and economical. Adams engineering college, paloncha eee department emii lab experiment no. Efficiency classes of singlespeed, three phase, cage induction motors iecode under 5. This experiment is included in vtu and autonomous syllabus. No load test of an induction motor no load test is an indirect method used for determining the efficiency and also to determine the circuit parameters of the equivalent circuit of the three phase induction motors. Conducting polarity test of new three phase induction motor is necessary before running into operation. Perform no load and block rotor test on 3 phase induction motor. A successful salesman for general electrics motor division once remarked to one of your instructors that, when asked by a customer how a motor. Three phase induction motors are one of the most popular electric motors commonly found in processing plants or any manufacturing concern. Induction motor torquespeed characteristics figure 6. To obtain the variation of no load power and current and blocked rotor power and current with changes in the applied voltage to the stator. The no load test is similar to the open circuit test on a transformer. Three phase induction motor working the video from learnengineering shows the working of three phase induction motors in animated form.
Thus from the working principle of three phase induction motor, it may be observed that the rotor speed should not reach the synchronous speed produced by the stator. Induction motor theory quiz free online electrician practice test questions on induction motor theory quiz. When a three phase induction motor connected to a single phase power supply using the steinmetz connection operates in a practical noload condition. Applications of three phase induction motors of size varying from half a kilowatt to thousands of kilowatts are numerous. The stator copper losses are 2 kw, and the rotor copper losses are 700 w. To obtain the load performance characteristics of a three phase squirrelcage induction motor. First no load test the no load test, like the open circuit test on a transformer, gives information about exciting current and rotational losses. The magnetization current im flowing in the motor s equivalent circuit fig. The results of the no load and blocked rotor tests on a three phase, 60 hp, 2200 v, sixpole, 60 hz, class a squirrelcage induction motor are shown below. Two digital multimeters and fluke power quality meter with banana cables from the. If the speeds become equal, there would be no such relative speed, so no emf induced in the rotor, and no current would be flowing, and therefore no torque would be generated. Connect the circuit as per diagram shown on attached sheet.
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