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The torque slip curve for an induction motor gives us the information about the variation of torque with the slip. The slip is defined as the ratio of difference of synchronous speed and actual rotor speed to the synchronous speed of the machine.
What is the slip?
Slip is the differentiation between synchronous and asynchronous speed. The difference between the synchronous speed of the electric motor magnetic field, and the shaft rotating speed is slip – measured in RPM or frequency. Slip increases with increasing load – providing a greater torque.
What is the relationship of torque and slip?
torque increases slip will decrease. torque transferred by the shifting element. When the actual torque exceeds the torque capacity, the shifting element will begin slipping and the actual torque is equal to the friction torque.
What is slip formula?
If the revolving magnetic flux’s synchronous speed & the speed of rotor are Ns & Nr in the motor, then the speed among them can be equivalent to (Ns – Nr). So, slip can be determined as. S = (Ns – Nr) / Ns.
What is slip in induction motor?
“Slip” in an AC induction motor is defined as: As the speed of the rotor drops below the stator speed, or synchronous speed, the rotation rate of the magnetic field in the rotor increases, inducing more current in the rotor’s windings and creating more torque. Slip is required to produce torque.
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 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.
How is slip torque calculated?
So, when slip s = R2 / X2, the torque will be maximum and this slip is called maximum slip Sm and it is defined as the ratio of rotor resistance to that of rotor reactance.
What is torque slip characteristics?
Torque Slip Characteristics of Three Phase Induction Motor. The torque slip curve for an induction motor gives us the information about the variation of torque with the slip. The slip is defined as the ratio of difference of synchronous speed and actual rotor speed to the synchronous speed of the machine.
Is torque proportional to slip?
Thus, the torque is inversely proportional to slip towards standstill conditions. We can represent the torque-slip characteristic by a rectangular hyperbola. For intermediate values of the slip, the graph changes from one form to another. In doing so, it passes through the point of maximum torque when R2 = sX20.
What happens when slip is zero?
Zero slip means that rotor speed is equal to synchronous speed. If rotor is rotating at synchronous speed in the direction of rotating magnetic field the, there will be no flux cutting action, no emf in the rotor conductors, no current in rotor bar conductor and hence no development of electromagnetic torque.
How is slip of Ship calculated?
Calculate the value of the propeller slip during this period. ( A nautical mile equals 1852 m.) Soln: Slip (percent) = Engine distance – ship’s distance/ Engine’s distance X 100. Engine distance = Pitch X RPM X 60 X 24 / 1852.
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 is slip in 3 phase induction?
This speed difference is called slip. Therefore, the difference between the synchronous speed Ns of the rotating stator field and the actual rotor speed N is called slip. The slip increase with load and is necessary for torque production. Slip speed is equal to the difference between rotor speed and synchronous speed.
What is the difference between rotor speed and synchronous speed?
Induction motor with squirrel cage rotor has two different speeds. The synchronous speed refers to the stator rotating magnetic field, which depends on the number of poles and frequency. The other speed is the rotor’s. The rotor speed will be always slower than the stator speed, we call it slip.
What is synchronous speed and slip?
Slip is the difference between the synchronous speed of a motor and its actual speed. Mathematically it is determined by. Slip = Synchronous Speed − Actual Speed. Using the example above for synchronous speed of a motor with four poles operating at 60 hertz, the value was calculated to be 1800 RPM.
What is the importance of slip?
Slip creates a relative speed between the RMF and rotor. That keeps a torque continuously acting on it when the motor is running. So what would happen if slip becomes zero? Bcoz there will be no relative speed between RMF and rotor, and which will stop inducing rotor current.
How do slip rings work?
HOW DOES A SLIP RING WORK? A slip ring passes electrical signals and power across a rotating interface using sliding electrical contacts. These contacts are typically a rotating ring and a stationary brush, or wiper, that slides along the ring surface during rotation.
What is slip percentage?
The difference between theoretically calculated forward speed based on angular speed of the rim and rolling radius, and actual speed of the vehicle, expressed as a percentage of the latter, is called ‘slip ratio’.
What is no load slip?
The speed is assumed to be synchronized. The synchronous speed can be achieved by taking slip = 0 which creates infinite impedance in the rotor branch. Rotor copper loss at no load is very less that its value is negligible. Small current is required to produce adequate torque.
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.
What is the slip frequency?
Slip frequency can be measured by determining the phase angle traversed in a defined period. For example, with a slip setting of 2 seconds (0.055 Hz) and slip frequency of 0.04 Hz, an angle of approx 29° (elec) is traversed before synchronising is permitted, as shown in Fig 12.15.
