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This is precisely the principle of operation of 3-phase induction motor. Slip creates a relative speed between the RMF and rotor. That keeps a torque continuously acting on it when the motor is running.
What is the importance of slip in an induction motor?
Slip of induction motor plays an important role in the operation of the induction motor. The torque produced by the induction motor is directly proportional to induction motor slip. At no-load induction motor requires small torque to meet with the frictional, iron and other losses, therefore slip is small.
What is slip in 3 phase induction?
Slip in Induction Motor is the relative speed between the rotating magnetic flux and rotor expressed in terms of per unit synchronous speed. It is a dimensionless quantity. The value of slip in induction motor is can never be zero.
What is slip power and its significance?
The slip power recovery (SPR) drive is an external system connected to the rotor circuit in place of the external resistors. The SPR provides speed and torque control like the resistors but can also recover the power taken off the rotor and feed it back into the power system to avoid energy waste.
What is slip in induction machine?
Definition: In Induction Motor, a slip is a speed among the rotary magnetic flux as well as rotor expressed in terms of for every unit synchronous speed. It can be measured in dimensionless & the value of this motor cannot be zero. induction-motor.
What are the main parts of 3 phase induction motor?
The stator of the three-phase induction motor consists of three main parts : Stator frame, Stator core, Stator winding or field winding.
What is normal slip of an induction motor?
Because of this speed difference, the motor rotates at a speed slightly slower than the synchronous speed. Slip is normally expressed in percentage. Slip of a power induction motor is 2 to 3% when the motor is operated under the rated load.
What is slip speed?
The speed at which the induction motor work is known as the slip speed. The difference between the synchronous speed and the actual speed of the rotor is known as the slip speed. In other words, the slip speed shows the relative speed of the rotor concerning the speed of the field.
What is the value of slip at starting of 3 phase induction motor?
The difference between synchronous and actual speed of the rotor is called slip. At start, slip of the motor is unity. When the motor starts accelerating, the slip decreases and at the rated KW the slip of the motor is about 3–5 % of the synchronous speed of IM.
Can slip be negative?
If the rotor of an induction machine rotates above synchronous speed, slip is negative, as are torque, mechanical output power and air gap power. i.e. the machine is operating as a generator. Rotational losses are 2450W.
What do you mean by slip power?
SLIP-POWER: A PART OF THE AIR-GAP POWER WHICH IS NOT CONVERTED INTO MECHANICAL POWER IS CALLED SLIP POWER. IT IS REPRESENTED BY sPg. where s=slip, Pg= air-gap powerSLIP RECOVERY: THE AIR GAP POWER WHICH IS GETTING WASTED IN ROTOR IS FED BACK TO THE SUPPLY MAINS THIS IS CALLED SLIP RECOVERY.
What are the advantages of slip power recovery system?
The main advantage of this method is that a smooth speed control is possible. Similarly wide range of speed control is possible. Another advantage of the system is that the design of a rotary converter is practically independent of the speed control required.
What are the types of slip power recovery system?
Slip Energy Recovery is one of the methods of controlling the speed of an Induction motor. This method is also known as Static Scherbius Drive. In the rotor resistance control method, the slip power in the rotor circuit is wasted as I2R losses during the low-speed operation.
What is full load slip?
The slip corresponding to full load speed of th motor is called full load slip. Example 1 : A 4 pole, 3 phase induction motor is supplied from Hz supply. Determine its synchronous speed. On full load, its speed is observed to be 1410 r.p.m. calculate its full load slip.
What are the operating modes of 3 φ induction motor?
There are three known operating modes: breaking mode for slip values between ∞ and 1, motor mode for slip values between 1 and 0, and generator mode for slip values between 0 and −∞ . All three operating modes are as part of torque characteristic shown in Figure 1.
What causes motor slip?
Slip depends on motor parameters The traditional way to control wound-rotor-induction-motor speed is to increase slip by adding resistance in the rotor circuit. The slip of low-hp motors is higher than that of high-hp motors because rotor-winding resistance is greater in smaller motors.
What are the applications of 3 phase induction motor?
Application of 3-Phase Induction Motors Pumps and submersible. Pressing machine. Lathe machine. Grinding machine. Conveyor. Flour mills. Compressor. And other low mechanical power applications.
What is the working of 3 phase induction motor?
Working of Three Phase Induction Motor The stator of the motor consists of overlapping winding offset by an electrical angle of 120o. When we connect the primary winding, or the stator to a 3 phase AC source, it establishes rotating magnetic field which rotates at the synchronous speed.
What are the 2 main parts of a 3 phase AC motor?
The Parts of the Motor A three-phase motor has two main parts: the rotor, which turns, and the stator that turns it.
Is 3-phase induction motor is self starting?
Three-phase induction motor is self-starting, because winding displacement is 120 degrees for each phase and supply also has 120 phase shift for 3-phase. It results in a unidirectional rotating magnetic field is developed in air gap which causes 3-phase induction motor to self-start.
Which type of motor is mostly used in the industry?
3-phase AC induction motors are the most widely used motors in industrial and commercial applications.
What is synchronous speed?
The synchronous speed is the speed of the revolution of the magnetic field in the stator winding of the motor. It is the speed at which the electromotive force is produced by the alternating machine. The Synchronous Speed is given by the relation shown below.
