A squirrel-cage rotor is the rotating part of the common squirrel-cage induction motor. It consists of a cylinder of steel laminations, with aluminum or copper conductors embedded in its surface. … The interaction of the magnetic fields of currents in the stator and rotor produce a torque on the rotor.
Why is the squirrel cage induction motor one of the most reliable machines used in industry?
Three-phase squirrel-cage induction motors are widely used as industrial drives because they are self-starting, reliable and economical. … VFDs offer especially important energy savings opportunities for existing and prospective induction motors in variable-torque centrifugal fan, pump and compressor load applications.
What is difference between squirrel cage and induction motor?
Key Differences Between Slip Ring & Squirrel Cage Induction Motor. The motor whose rotor is wound type such type of motor is called slip ring induction motor, whereas the squirrel cage motor, has a squirrel cage type rotor. … The starting torque of the slip-ring motor is high, whereas in squirrel cage motor it is low.
What are the advantages of squirrel cage motor?
Some advantages of squirrel cage induction motors are:
- Simple and rugged construction.
- The low initial as well as the maintenance cost.
- Maintains constant speed.
- The overload capacity is high.
- Simple starting arrangement.
- High power factor.
- Low rotor copper loss.
Why is squirrel cage induction motor preferred?
Advantages of Squirrel Cage Induction Motor
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)
What 3 things are needed for an induction motor to work?
A 3-phase induction motor includes two essential components namely the stator & the rotor. In this motor, the stationary part is the stator whereas the rotating part is the rotor. In this motor, the load is connected to the shaft. Three-phase armature winding can be wound over the stator.
What are the disadvantages of squirrel cage induction motor?
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.
Why the starting torque of squirrel cage induction motor is low?
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.
What type of starter Cannot be used for squirrel cage motors?
So we cannot use is this method for starting. Important Points: The star-delta starter method of starting three-phase induction motors is very common and widely used among all the methods.
What is meant by squirrel cage?
1 : a cage for a small animal (such as a squirrel) that contains a rotatable cylinder for exercising. 2 : something resembling the working of a squirrel cage in repetitiveness or endlessness.
Why is the speed of the squirrel cage motor fixed?
‘Fixed’ speed induction generators
Because the speed variation from no load to full load is very small, the term ‘fixed’ speed tends to be widely used. … The design and construction of the stator and rotor of an induction generator are similar to that of a large induction motor having a squirrel-cage rotor.
What kind of Cage does a squirrel need?
A pet squirrel will require a cage that is at least two feet wide, two feet deep, and several feet tall (about 0.6 meters wide, 0.6 meters deep, and at least a meter tall.) Squirrels are active animals and need to be able to move around.
What are types of induction motor?
Types of Induction Motors
- Split Phase Induction Motor.
- Capacitor Start Induction Motor.
- Capacitor Start and Capacitor Run Induction Motor.
- Shaded Pole Induction Motor.
What are the advantages of double squirrel cage induction motor?
The advantage of a double-squirrel cage motor is that it provides high starting torque and low starting current.
What are the advantages of a wound rotor motor over a squirrel cage motor?
Another important advantage over squirrel-cage motors is higher starting torque. The speed and torque characteristics of a wound-rotor motor can be adjusted by changing the external resistance, unlike a squirrel cage motor which has a fixed characteristic. This is useful for speed control of the motor.
What defect is found in squirrel cage motors?
Squirrel cage induction motor cast rotor defect detection with magnetic field analysis.
Why starter is used in induction motor?
⇒ The starter is a device which is basically used to limit the starting current by supplying reduced voltage to the motor at the time of starting. From the expression of rotor current it can be seen that the current at start can be controlled by : By reducing the supply voltage at the time starting.
Is 3 phase induction motor is self-starting?
Three-phase induction motor is self-starting, because winding displacement is 120 degrees for each phase and supply also has 120 phase shift for 3-phase. It results in a unidirectional rotating magnetic field is developed in air gap which causes 3-phase induction motor to self-start.
Is AC motor and induction motor same?
The two main types of AC motors are induction motors and synchronous motors. The induction motor (or asynchronous motor) always relies on a small difference in speed between the stator rotating magnetic field and the rotor shaft speed called slip to induce rotor current in the rotor AC winding.
What are the advantages of slip ring induction motor over squirrel cage?
Slip ring induction motor have big advantage of having high starting torque compared to squirrel cage motor. Therefore slip ring induction motors are generally employed where load requires high starting torque or good speed control.
Why starting current is high?
This high current in the rotor will create its own magnetic field which opposes the main stator magnetic field, this weakens the stator magnetic field so the back EMF in the stator will drop and the supply voltage will be much higher than the stator back EMF and so the supply current increases to a high value.
Why squirrel cage rotor is short circuited?
Shorting of rotor bars in form of squirrel cage cause the suitable low impedance path for rotor induced currents. The impedance characteristics (R & X) of rotor winding infects the motor performance, starting torque, and total losses consequently motor efficiency.
Does squirrel cage motor have brushes?
Construction: A slip ring motor gest a complex construction owing to the use of slip rings and brushes, whereas, squirrel cage motors are simply-built. .