What is torque speed characteristic of induction motor?
The torque-speed characteristics of a 3-phase induction motor is defined as the curve plotted between torque developed and rotational speed of the motor. It gives the information about variation in the motor torque with the change in its speed.
How torque is produced in the rotor of an induction motor?
The rotor windings in an induction motor are either closed through an external resistance or directly shorted. Therefore, the e.m.f induced in the rotor causes current to flow in a direction opposite to that of the revolving magnetic field in the stator and leads to a twisting motion or torque in the rotor.
What is the relation between torque and speed in an induction motor?
Since the rated output power of a motor is a fixed value, speed and torque are inversely related. As output speed increases, the available output torque decreases proportionately. As the output torque increases, the output speed decreases proportionately.
What are the characteristics of torque?
Torque is proportional to voltage squared and the current is proportional to the voltage. So, if the stator voltage is reduced the speed reduces and similarly if the stator voltage is increased the speed also increases.
What is speed characteristic?
Characteristic speed is a physical quantity characterizing the average speed of motion of particles inside a single body or a particle system at rest.
What is induction motor characteristics?
The induction motor torque varies from zero to full load torque as the slip varies. The slip varies from zero to one. It is zero at no load and one at standstill. From the curve it is seen that the torque is directly proportional to the slip.
What is rated speed of induction motor?
Rated speed is the base speed minus the slip at full rated load. An induction motor slows as it is loaded. The induction motor must run at a speed below the revolving stator field flux. Forward motion is due to the current flowing in the cage winding.
What is torque slip characteristics of 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.
What is the torque speed relationship?
What is the Relationship Between Torque and Speed? The mathematical formula tells us that this force around an axis is inversely proportional to speed (angular velocity). This means that an increase in velocity causes torque to drop and vice versa.
What is the torque slip characteristics of an induction motor?
What is relation between torque and speed?
Torque is the rotational equivalence of linear force. Speed measures the distance covered in unit time. The relation between torque and speed are inversely proportional to each other.
What is%torque speed characteristic of induction motor?
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.
How to control the speed of wound ring induction motor?
The speed of the wound rotor or slip ring induction motor can be controlled by varying the resistance in the rotor circuit. This method is applicable to slip ring induction motor only. When the motor is running and if the full resistance is connected in the rotor circuit the speed of the motor decreases.
What is a wound rotor induction motor?
A wound rotor induction motor has a stator like a squirrel cage induction motor, but a rotor with insulated windings brought out via slip rings and brushes. However, no power is applied to the slip rings.
How does a slip ring motor increase the torque?
In a slip ring or wound rotor induction motor, the torque is increased by adding external resistance in the rotor circuit from a star-connected rheostat. This rheostat resistance is gradually cut out as the speed of the motor increases. This additional resistance increases the rotor impedance hence also reduces the rotor current.