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 the maximum value of slip in induction motor?
This is maximum value of slip s possible for induction motor which occurs at start. While s = 0 given us N = Ns which is not possible for an induction motor. So slip of induction motor can not be zero under any circumstances. Practically motor operates in the slip range of 0.01 to 0.05 i.e. 1 % to 5 %.
What happens when slip is 0?
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 the value of slip at starting?
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.
What is slip and slip speed of an induction motor?
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.
How is percentage slip calculated?
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 the range of slip of induction motor for no load?
Q1 A 3-phase, 6-pole, 50 Hz induction motor has a slip of 1% at no-load and 3% at full-load.
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. … If slip is negative, the “input power” to the electrical terminals will be negative, implying that power is flowing out of the electrical terminals.
What is slip in an induction motor explain why slip is never zero in an induction motor?
In motors the number of rotor slots and stator slots are different and thus cogging (magnetic locking) can’t happen. And thus The slip motor can’t run at rated speed. Torque developed by induction motor is proportional to the slip. At synchronous speed,slip is zero and hence torque developed by the motor is zero.
What is the importance of slip in 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 ring in induction motor?
A wound-rotor motor, also known as slip ring-rotor motor, is a type of induction motor where the rotor windings are connected through slip rings to external resistance. Adjusting the resistance allows control of the speed/torque characteristic of the motor. … Each pole is wired in series with a variable power resistor.
What is the slip of induction motor at starting?
When the supply is connected to the stator of a three-phase induction motor, a rotating magnetic field is produced, and the rotor begins rotating and the induction motor starts. At the time of starting, the motor slip is unity, and the starting current is very large.
What is slip in induction generator?
An induction generator produces electrical power when its rotor is turned faster than the synchronous speed. … The motor normally turns slightly slower than the synchronous speed; the difference between synchronous and operating speed is called “slip” and is usually expressed as per cent of the synchronous speed.