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The main disparity between the synchronous & actual speed is known as the SLIP. The slip value is equal to ‘1’ as the rotor in the motor is at rest & it will not equivalent to ‘0’.
What is the value of 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.Synchronous Speed. Number of Poles Synchronous Speed NS in r.p.m 10 600 12 500.
What is the slip at synchronous speed?
“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.
What is slip speed formula?
Slip speed is the speed difference between the Synchronous speed and Rotor speed. Slip speed = Synchronous speed – Rotor speed = Ns -N. Slip, s = (Ns – N) / Ns.
What is value of slip at no load?
At no-load condition, the rotor speed is almost equal to the synchronous speed. e.g A 4 pole, 60 Hz induction motor at no load turning at ηr = 1790 RPM will have slip = (1800 – 1790)/(1800) = 0.55%Mar 9, 2020.
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.
What is called synchronous speed?
: a definite speed for an alternating-current machine that is dependent on the frequency of the supply circuit because the rotating member passes one pair of poles for each alternation of the alternating current.
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 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.
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.
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.
How is motor rating slip calculated?
You can also calculate the slip rating by subtracting the rated full load speed from the synchronous speed, dividing that answer by the synchronous speed and multiplying that answer by 100: ((synchronous speed-rated full-load speed) / (synchronous speed)) x 100 = slip rating.
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 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.
Why must slip be present for motor Action?
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 type of motor has a slip factor of 0 %?
In two-pole single-phase motors, the torque goes to zero at 100% slip (zero speed), so these require alterations to the stator such as shaded-poles to provide starting torque. A single phase induction motor requires separate starting circuitry to provide a rotating field to the motor.
When slip is zero rotor will?
If Slip is equal to zero, rotor current is zero and torque is zero. The zero torque means motor will not rotate at all.
Why there is no slip in synchronous motor?
Because the rotor turns at the same speed as synchronous speed (speed of the rotating magnetic field), there is no slip. The speed of rotation of the motor is constant in a synchronous motor, and does not vary with load, as in an induction motor.
Why it is called synchronous machine?
A synchronous generator is called “synchronous” because the waveform of the generated voltage is synchronized with the rotation of the generator. A synchronous generator is essentially the same machine as a synchronous motor. The magnetic field of the rotor is supplied by direct current or permanent magnets.
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 meant by synchronous current?
If two alternators generating exactly the same emf are perfectly synchronized, there is no resultant emf acting on the local circuit consisting of their two armatures connected in parallel. No current circulates between the two and no power is transferred from one to the other.
