Which starter gives better starting torque to squirrel cage induction motor?
Which starter gives better starting torque to squirrel cage induction motor?
The Delta Start Starter is ideally suited for High Starting torque application, where squirrel cage induction motor is selected up to 50HP capacity. The Delta Star Starter also improves the power factor & reduces the demand on power supply system.
How starting torque of a squirrel cage induction machine SQIM can be improved?
The starting torque of the squirrel cage induction motor can be improved if the rotor resistance is increased. The double cage squirrel cage induction motor is used for the application which requires higher starting torque.
What is the starting torque of a squirrel cage?
Low Starting Torque, 1.25 times of full load torque when full voltage is applied.
What is the reason of low starting torque of a squirrel cage induction motor?
It suffers from the disadvantage of a low starting torque. It is because the rotor bars are permanently short-circuited and it is not possible to add any external resistance to the rotor circuit to have a large starting torque.
Which starting method is best for induction motor?
The direct on-line starter method, of an induction motor, is simple and economical. In this method, the starter is connected directly to supply voltage. By this method, small motors up to 5 kW rating are started to avoid the supply voltage fluctuation.
Which of the motor has high starting torque?
DC Series Motor: In a DC series motor, torque is directly proportional to the flux and armature current. The torque-speed characteristics of different DC motors are shown below. Therefore, the starting torque of the DC series motor is highest among all the DC motors.
How do you increase the torque of a motor?
Please suggest a circuit to accomplish it. To increase the torque (if 9V won’t get it high enough) you can increase the supply voltage, and to decrease the speed you can pulse width modulate (PWM) the supply input to the motor.
What should you do to achieve maximum starting 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.
How do you start a squirrel cage induction motor?
Squirrel Cage Induction Motor Starting Methods As the name suggests, the induction motor is started by connecting it directly to three-phase supply. In this method, the motor draws a high starting current (about 4 to 7 times of the rated current) and at low power factor.
How will you address the low starting torque issue of an induction motor?
There are three ways to improve the starting torque of Single phase induction Motor
- Internal Rotor Resistance. The across the line starting torque at low speed can be increased by increasing the rotor resistance.
- External Rotor Resistance.
- Variable Voltage/Frequency.
Why the starting torque of induction machine is higher?
In order to increase the starting torque, extra resistance should be added to the rotor circuit at start and cut out gradually as motor speeds up. The maximum torque is directly proportional to square of rotor induced emf at the standstill. The maximum torque is inversely proportional to rotor reactance.
What is the condition for maximum starting torque?
Maximum starting torque will obtained when R = X i.e. the rotor resistance should exactly equal to the reactance at standstill. Under such condition rotor power factor is 0.707 lagging (presence of inductance).
