How a double caged squirrel cage induction motor deliver higher starting torque than a single caged rotor?

So to provide a higher value of rotor resistance in squirrel cage induction motor double bar double cage rotor is used in induction motor. The motive is to provide higher value of rotor resistance in such a manner that the rotor with its higher valued resistance provides higher torque and more efficiency.

What type of squirrel cage rotor has the highest starting torque?

Class D Design. In this Design of Class motors has very high starting torque (275 percent or more of the rated torque).

What is the starting torque of a squirrel cage induction motor?

Starting Torque of Squirrel Cage Motors – For the squirrel cage motors, the starting torque is very low about 1.5 to 2 times of the full-load value. Starting Torque of Wound Rotor Motors – In case of slip ring induction motors, the resistance of the rotor circuit can be increased by inserting external resistance.

What is the difference between squirrel cage and wound rotor induction motor?

The slip ring motor is also called phase wound rotor. The copper loss in the phase wound motor is high as compared to squirrel cage motor. The efficiency of the slip ring motor is low whereas the squirrel cage motor has high efficiency. The speed of the phase wound motor is controlled by using the resistance circuit.

How the double cage induction motor develops high torque at starting and yet gives a good running performance?

Because of the high reactance of the lower winding, nearly all the rotor current flows in the high-resistance outer cage winding. This provides the good starting characteristics of a high-resistance cage winding. Thus the outer winding gives high starting torque at low starting current.

What is a double cage rotor?

A Double Cage Induction motor is that type of motor in which a double cage or two rotor windings or cages are used. This arrangement is used for obtaining high starting torque at a low value of starting current. In the double cage rotor of an induction motor, there are two layers of the bars.

Which type of induction motor has high starting torque?

Why Slip ring Induction motor is preferred for High starting Torque application | Electrical4u.

Does induction motor have high starting torque?

Slip ring induction motor has high starting torque. Because slip ring is connected through the resistance. When the supply is on the resistance is increases the phase difference is decrease due to this starting torque is increases.

What is starting torque in induction motor?

Locked Rotor or Starting Torque The Locked Rotor Torque or Starting Torque is the torque an electrical motor develops when starting at zero speed. A high Starting Torque is more important for application or machines hard to start – like positive displacement pumps, cranes etc.

How starting torque of an induction motor can be increased?

The across the line starting torque at low speed can be increased by increasing the rotor resistance. This will decrease the efficiency of the motor, and the heat on the rotor.

What is double cage induction motor?

A Double Cage Induction motor is that type of motor in which a double cage or two rotor windings or cages are used. This arrangement is used for obtaining high starting torque at a low value of starting current.

What is double cage rotor induction?

Why are double cage rotors used in induction motors?

This arrangement is used for obtaining high starting torque at a low value of starting current. The stator of a double cage rotor of an induction motor is the same as that of a normal induction motor. In the double cage rotor of an induction motor, there are two layers of the bars.

What is the starting torque of a double squirrel cage motor?

Fig: 3.39 shows the operating characteristics of double squirrel-cage motor. The starting torque of this motor ranges from 200 to 250 percent of full-load torque with a starting current of 4 to 6 times the full-load value. It is classed as a high-torque, low starting current motor.

How to solve the problem of higher starting torque in induction motor?

Thus, problem of higher starting torque is solved by double cage induction motor. Given below is the fig. showing torque-slip characteristics of double cage induction motor. It is assumed that two cages develop separate torques. The total torque of the motor is equal to the sum of the torque of each cage.

What is the difference between single cage and double cage rotors?

As compare to double cage rotor, the single cage has less starting torque so at starting less heating loss occur. A double cage motor develops higher starting torque for low starting current and its rotor heating loss is more. 2. Full-load performance. Full load slip is higher than double cage rotor.