Table of Contents
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.
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.
What will happen if the slip is one?
When the Value of Slip is >1 If the slip value of the motor is greater than one then the rotor will turn in the opposite direction to the revolution of magnetic flux. So if the magnetic flux is revolving in the direction of clockwise, then the rotor will turn rotating in the anti-clockwise direction.
What is slip formula?
Formula to find slip = (ns – n) x 100/ns. substitute the values in the above formulas. speed difference = 1500 – 1450. = 50. slip = 50/1500 x 100.
What is positive slip?
A positive slip indicates that the wheels are spinning; negative slip indicates that they are skidding. Locked brakes, , means that and sliding without rotating.
What will happen when the slip is 100% and zero?
What will happen when the slip is 100 and zero? As the rotor ends are short circuited current flows through the rotor. So when slip is zero there is no phase difference between stator flux and rotor flux and there is no torque exerted on rotor and rotor does not rotate .
What is slip and significance of slip?
What is the significance of slip? The induction motor is called asynchronous motor because the actual speed of the motor is always less than its synchronous speed. The difference in the actual speed and the synchronous speed is called slip. The torque of the motor depends on the slip.
What is slip in DC motor?
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 unit of slip?
Slip is expressed in meters per second (m/s). It’s the relative speed between the wheel’s contact point and the colliding surface.
What is full load slip?
At full load the speed of the motor is 1350 rpm. Hence slip at full load = 5.33% When the motor is so loaded that the rotor speed is reduced to 0, the value of Slip is 1. Hence, value of Slip gradually increases from no-load to full load.
What is speed of 3phase induction motor at slip is zero?
The value of slip in induction motor is can never be zero. As we know that, the speed of rotor cannot be equal to synchronous speed i.e. Nr < Ns, the value of slip s is always less than one. For induction motor, 0<s<1.
What does negative slip mean?
Negative slip indicates that the motor is running above synchronous speed. This can happen only when it is driven by a prime mover. This motor becomes an induction generator.
What is the slip?
A slip is a woman’s undergarment worn beneath a dress or skirt. A full slip hangs from the shoulders, usually by means of narrow straps, and extends from the breast to the fashionable skirt length. A half slip (or waist slip) hangs from the waist.
What causes motor slip?
The interaction of currents flowing in the rotor bars and the stators’ rotating magnetic field generate torque. In actual operation, rotor speed always lags the magnetic field’s speed, allowing the rotor bars to cut magnetic lines of force and produce useful torque. This speed difference is called slip speed.
What is the value of slip at starting?
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.
How is slip speed 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 value of slip at stand still?
When the motor is at standstill, the relative speed of the rotating magnetic field and the rotor is equal to 1. The difference in the synchronous speed of the motor and the actual speed of the rotor is unity. In other words, the slip of the motor is unity when the rotor is at standstill.
What is the significance of slip?
Importance of Slip Hence, torque is directly proportional to slip. The above equation shows that the torque induces on the rotor is directly proportional to the slip of the induction motor. The high value of slip induces the emf in the rotor. This EMF develops the heavy torque on the rotor conductors.
What is rotor slip?
“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.
Why must slip be present for Motor Action?
Because of the above phenomenon, the rotor speed “N” is always less than the synchronous speed “Ns” which keeps the motor moving. This difference between synchronous speed of the rotating magnetic field and synchronous speed is known as slip. Hence slip is an essential feature for proper working of the induction motor.
What is negative slip in pump?
Slip of a reciprocating pump is equal to the difference of theoretical discharge and actual discharge of the pump. In that case, the slip of the pump is known as negative slip. Negative slip occurs when delivery pipe is short, suction pipe is long and pump is running at high speed..
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.
