What is the torque of squirrel cage induction motor?
What is the torque of 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 are the characteristics of induction motor squirrel cage type?
They are low cost. Require less maintenance (as there are no slip rings or brushes) Good speed regulation (they are able to maintain a constant speed) High efficiency in converting electrical energy to mechanical energy (while running, not during startup)
How does torque increase in squirrel cage induction motor?
The starting torque of squirrel cage induction motor can be increased by using double squirrel cage rotor. In this case, rotor has two sets of independent cages. Upper cage has high resistance and low reactance while lower cage has low resistance and high reactance.
Why the starting torque of squirrel cage induction motor is low?
The motor draws about 5 to 6 times current of its full load current and produce very less torque. The most of the current is reactive in nature and does not contribute in production of torque. That is why the starting torque of the squirrel cage induction motor is poor.
Why does squirrel cage induction motor have low starting torque?
At start, the rotor reactance is large because slip of the motor at start is equal to unity. The large rotor reactance at start makes the starting torque of the motor poor. The motor draws about 5 to 6 times current of its full load current and produce very less torque.
Which type of induction motor has high starting torque?
Capacitor-start motor: The capacitor-start motor develops a much higher starting torque, i.e. 3.0 to 4.5 times the full-load torque.To obtain a high starting torque, the value of the starting capacitor must be large, and the resistance of starting winding must be low.
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.