Table of Contents
What is slip torque?
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 at maximum torque?
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. NOTE: At starting S = 1, so the maximum starting torque occur when rotor resistance is equal to rotor reactance.
Does torque mean slippage?
Torque is the twisting force that the engine produces. The torque from the engine is what moves your car. The car that makes a good start never exceeds this torque, so the tires don’t slip; the car that makes a bad start exceeds this torque, so the tires slip.
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 is pull out torque in synchronous motor?
Pull out Torque: At load angle 90 degree the motor produces the maximum torque. Further increasing the loads, the magnetic locking between the stator and rotor become weak. Then the motor stops. Therefore, the maximum torque is produced by the motor without loss of synchronism is called pull out Torque.
What is rated torque of induction motor?
The rated torque takes into account the spinning (magnetic) losses and thermal (I2T) losses of the motor. At 0 speed, these losses are 0 and thus the stall torque is higher than the rated torqued.
How is rated torque calculated?
Torque (lb.in) = 63,025 x Power (HP) / Speed (RPM) Power (HP) = Torque (lb.in) x Speed (RPM) / 63,025. Torque (N.m) = 9.5488 x Power (kW) / Speed (RPM) Power (kW) = Torque (N.m) x Speed (RPM) / 9.5488.
How do you calculate pullout torque?
The maximum torque or pull-out torque, which occurs at the slip s=spo. Once a machine has reached rated operating point, this is the maximum torque that can be applied without stalling the machine (pulling out).
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 maximum torque?
Torque is defined as τ = rF sin θ, where F is the force, r is the distance from the pivot that the force is applied, and θ is the angle between r and F. (b) The maximum torque occurs when θ is a right angle and sin θ = 1. (c) Zero (minimum) torque occurs when θ is zero and sin θ = 0.
What is relation between torque and slip?
Torque is easily understood as force x distance with the component of the force at right angles to the distance. Slip is the difference between two velocities, of pretty well anything. Slip in a mechanical system is the speed difference between two moving parts.
How is motor rated torque calculated?
To calculate load torque, multiply the force (F) by the distance away from the rotational axis, which is the radius of the pulley (r). If the mass of the load (blue box) is 20 Newtons, and the radius of the pulley is 5 cm away, then the required torque for the application is 20 N x 0.05 m = 1 Nm.
How do you get maximum torque?
Note that the torque is maximum when the angle is 90 degrees. A practical way to calculate the magnitude of the torque is to first determine the lever arm and then multiply it times the applied force. The lever arm is the perpendicular distance from the axis of rotation to the line of action of the force.
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 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 happens if fifth harmonics is given to induction motor?
It will rotates in normal operation. Either short circuit or open circuit occurs. The sinusoidal components having frequency five times of fundamental are known as fifth harmonics. Hence induction motor will rotates in reverse direction because of reverse phase sequence of fifth harmonics.
What is the relation between torque and speed?
Torque is inversely proportional to speed. Thus, when speed increases, torque will decrease.
What is torque speed characteristics?
Torque Speed Characteristic is the curve plotted between the torque and the speed of the induction motor. We have already discussed the torque of the induction motor in the topic Torque Equation of an Induction motor.
What is cogging and crawling in 3 phase induction?
The important characteristics normally shown by a squirrel cage induction motors are crawling and cogging. These characteristics are the result of improper functioning of the motor that means either motor is running at very slow speed or it is not taking the 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 rated torque?
Rated torque is the maximum continuous torque available at the design speed that allows the motor to do the work without overheating. Starting torque is the torque the motor delivers at zero speed. i.e. startup. It is also called the stall torque.
