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For a single phase motor, this can be done by connecting a capacitor in series with the starting windings. For three phase motors, this can be done by connecting starting resistors in the stator windings at starting. This reduces the stator current and hence it's flux density. Thus the rotor will have less opposition starting to rotate. Hence, the torque has increased.
What else can I help you with?
What type of motor is used in centrifugal pump?
3 Phase induction motor because it produce high torque at starting
What is the maximum torque than an induction motor can develop known as?
Gross Torque
How does an induction motor develop torque?
The shaft of an AC induction motor rotates because of the torque created by the interaction between the magnetic field of the stator and the magnetic field of the rotor.
What are the different types of induction motors?
DOL(Direct Online starting) Star Delta starting Auto transformer starting Above methods are for squirrel cage induction motor Rotor resistance starting is used for wound rotor or slip ring induction motor
Pull-out torque of induction motor?
The pullout torque is the maximum torque a motor can achieve. Also known as breakdown or peak torque. It occurs at the point where, the increase in the rotor current is exactly balanced by the decrease in the rotor power factor.
What will happen to speed-torque characteristics of an induction motor is the rotor resistance is increased?
If Rotor resistance is increased torque is increased
What are the advantages of induction motor?
1. Induction motor has high starting torque, therefore use for operate pump which need high starting torque. 2. Induction motor operate on variable speed. 3. It can be used as generator when speed of motor is higher than synchronous speed.
Why speed of the induction motor falls when load is increased?
As the load increases, the speed reduces to deliver the increased torque required.
What is the use of double cage rotor in induction motor?
to obtain high starting torque
Performance curve of a single phase induction motor?
The performance curve can be a graph of torque versus speed. The torque is zero at zero speed and also at the synchronous speed. Normally an induction motor operates at 90-97% of the synchronous speed, where the slip is between 10% and 3%. In this region the torque is proportional to the slip. As the torque is increased the speed falls until the motor stalls and the speed drops to zero. Below the stalling speed the torque rises between zero speed and the stalling speed. Because the torque is 0 at 0, a single-phase induction motor needs a separate starting winding fed by a starting capacitor to produce a little positive torque that starts the motor.
What type of motor is used in centrifugal pump?
3 Phase induction motor because it produce high torque at starting
Disadvantages of a squirrel cage motor?
Squirrel Cage Induction Motor Disadvantages:Some of disadvantages or demerits of squirrel cage induction motors are listed below:Main disadvantage of squirrel cage induction motor is that they have poor starting torque and high starting currents. Starting torque will be in the order of 1.5 to 2 times the full load torque and starting current is as high as 5 to 9 times the full load current. In slip ring induction motors, higher starting torque can be attained by providing an external resistance in the rotor circuits during starting of the slip-ring induction motor. This arrangement in slip-ring induction motors also reduces the high inrush currents during starting of induction motor.Squirrel cage induction motors are more sensitive to the supply voltage fluctuations. When the supply voltage is reduced, induction motor draws more current. During voltage surges, increase in voltage saturates themagnetic components of the squirrel cage induction motor.Speed control is not possible in squirrel cage induction motor. This is one of the major diadvantages of squirrel cage induction motors.The total energy loss during starting of squirrel cage motor is more compared to slip ring motors. This point is significant if the application involves frequent starting
What is induction motor?
Induction motor is an AC electric motor which uses electromagnetic induction to induce the electric current in the rotor to produce torque.
Disadvantages of 3 phase induction motor?
One of the disadvantages of the 3 phase induction motor is that it requires a three wire supply. The other disadvantage is that the 3 phase induction motors have poor starting torque and high have in the rush currents.
How do you increase starting torque in cage type 3-phase induction motor's?
by adding external resistance to the shaft of rotor
What is the maximum torque than an induction motor can develop known as?
Gross Torque
Why induction motor current increase when load increase?
The slip is proportional to the load torque in an induction motor. This can also be seen as a reduction in speed causing extra current to be induced in the rotor to supply the increased torque.
