Polyphase induction motors are mainly of two types by construction squirrel cage and wound-rotor(with slip-rings). In the case of a squirrel cage induction motor the rotor is inaccessible and rotor circuit resistance is xed whereas the wound-rotor machines are provided with slip-rings by which additional resistance
Learn MorePolyphase induction motors are mainly of two types by construction squirrel cage and wound-rotor(with slip-rings). In the case of a squirrel cage induction motor the rotor is inaccessible and rotor circuit resistance is xed whereas the wound-rotor machines are provided with slip-rings by which additional resistance
Learn MoreThe per-phase equivalent circuit of an induction motor is shown in Figure 1. The circuit impedances are defined (in Ohms) by the following R 1 stator resistance . X 1 stator leakage reactance . X m magnetizing reactance . R. c. machine core loss resistor . X. 2. rotor leakage reactance . R. 2. rotor resistance
Learn MoreRotor resistance R 2 is constant and if slip s is small then (sX 2) 2 is so small that it can be neglected. Therefore T ∝ sE 2 2 where E 2 is rotor induced emf and E 2 ∝ V
Learn MoreJun 02 2015 · Relation Between Torque and Rotor Power Factor. In Art. 29.7 it has been shown that in the case of a d.c. motor the torque Ta is proportional to the product of armature current and flux per pole i.e.Ta µ f Ia.Similarly in the case of an induction motor the torque is also proportional to the product of flux per stator pole and the rotor
Learn MoreTherefore simultaneous estimation of the motor speed and the rotor resistance is required. This paper presents a method of estimating simultaneously the motor speed and the rotor resistance of an induction motor
Learn MoreIn general the induction motor is cheaper and easier to maintain compared to other alternatives. The induction motor is made up of the stator or stationary windings and the rotor. The stator consists of a series of wire windings of very low resistance permanently attached to the motor
Learn MoreJun 02 2015 · Relation Between Torque and Rotor Power Factor. In Art. 29.7 it has been shown that in the case of a d.c. motor the torque Ta is proportional to the product of armature current and flux per pole i.e.Ta µ f Ia.Similarly in the case of an induction motor the torque is also proportional to the product of flux per stator pole and the rotor
Learn MoreApr 04 2019 · To overcome this problem the slip ring induction motor comes into the picture. The working principles and stator construction of the slip ring induction motor are exactly the same as that of the squirrel cage motor. However the rotor construction of the slip ring motor is quite interesting. Instead of bars in this motor
Learn MoreSolution for A six pole 3-0 50 Hz induction motor has a rotor resistance and rotor reactance of 0.02 Q and 0.13 O respectively at stand still. The external
Learn MoreApr 16 2020 · If the motor is kept in a place with high humidity a periodical inspection is necessary. It is practically impossible to determine rules for the actual minimum insulation resistance value of a motor because resistance
Learn MoreA three phase induction motor is a type of AC induction motors which operates on three phase supply as compared to the single phase induction motor where single phase supply is needed to operate it. The three phase supply current produces an electromagnetic field in the stator winding which leads to generate the torque in the rotor winding of three phase induction motor
Learn MoreRotor resistance control of induction motor. In above we saw three starters for effective starting of I.M but is the case of slip ring induction motor it would be much easier to start the motor. In slip ring induction motor we can add external resistance in rotor
Learn More10) From fig 5.2 the critical slip at which motor produces maximum torque is proportional to the rotor resistance. 11) With the increase in rotor resistance the critical slip value also increase for example for a constant load torque (TL ) the motor operating points shift from A to B to C with change in order of resistance.
Learn MoreThe value of starting current is adjusted by adding up external resistance to its rotor circuit. Incase of a squirrel cage induction motor the value of rotor resistance is very low which leads to heavy starting current requirement. But in case of slip ring motors the rotor resistance is increased by the addition of external resistance.
Learn MoreJul 23 2020 · -Static Rotor Resistance (Rheostatic) Control Method. -V/F Control Method. -Applications of three phase I.M.
Learn MoreDec 17 2019 · Where E 2 is the rotor emf N s is the synchronous speed R 2 is the rotor resistance X 2 is the rotor inductive reactance. The Speed of Induction Motor is changed from Both Stator and Rotor Side. The speed control of three phase induction motor from stator side are further classified as
Learn MoreInduction Motor DC test for Stator Resistance. In the DC test of Induction Motor dc supply is given at the stator of induction motor. As input is DC so there will be no induced voltage in the rotor and no current will move in the DC. The reactance (X r) of the motor
Learn MoreFor a 3 phase wound rotor motor Controlling the rotor resistance allows for controlling the starting current the speed and the torque. It also provides a way to recover the power generated by the increased slip by converting the slip energy to
Learn MoreMay 30 2018 · Rotor copper losses (losses in the rotor resistance) I 2.R. P rc = 3.I 2 2 R 2. Rotor core losses (hysteresis and eddy current losses in the rotor core) P r (h e) To achieve the maximum efficiency of induction motor the rotor
Learn MoreSep 10 2019 · Speed Control of Slip Ring Induction Motor. 1) By Varying External Resistance We know that a motor uses an external high resistance circuit for producing high starting torque. The resistance of this motor depends upon the slip and independent of the torque. So by varying resistance after the motor
Learn More3). What is a slip ring induction motor A motor with a wound-type rotor is known as a slip ring induction motor. Also rotor windings are connected through slip rings to external resistance. 4). Name one disadvantage of slip ring induction motor and squirrel cage induction motor
Learn MoreInduction Motor DC test for Stator Resistance. In the DC test of Induction Motor dc supply is given at the stator of induction motor. As input is DC so there will be no induced voltage in the rotor and no current will move in the DC. The reactance (X r) of the motor will also 0 at DC. So the only element which is restring the current in
Learn MoreSolution for A six pole 3-0 50 Hz induction motor has a rotor resistance and rotor reactance of 0.02 Q and 0.13 O respectively at stand still. The external
Learn MoreAn induction motor or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. An induction motor can therefore be made without electrical connections to the rotor. An induction motor s rotor can be either wound type or squirrel-cage type.
Learn MoreOct 04 2017 · In short the starting performance of the motor is improved with large rotor resistances while the running performance is impaired. To get the advantages of a high rotor resistance at starting an additional resistance is connected in the rotor circuit of the wound rotor induction motor and slowly cut off as the rotor accelerates. At rated speed the motor operates on its natural characteristic.
Learn MoreRotor Resistance Control is also one of the methods by which we can control the speed of the Induction motor. The speed of the wound induction motor can be controlled by connecting an external resistance in the rotor circuit through slip rings. This method is not applicable to cage rotor induction motor.
Learn MoreJun 05 2018 · In this method the resistance of rotor circuit is varied to have speed control. Please read Rotor Circuit Resistance Control of Induction Motor for detail. Speed Control Methods from Stator Side. Following are the various methods of speed control of Induction Motor
Learn MoreThe slip ring induction motor has a high starting torque as the resistance of the rotor winding is increased by adding the external resistance to it. The starting torque is increased as the power factor of the rotor circuit gets improved during starting.
Learn MoreR 1 is the stator resistance.. R 2 is the rotor resistance with respect to the stator.. L 1 is the stator inductance.. L 2 is the rotor inductance with respect to the stator.. L m is magnetizing inductance.. s is the rotor
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