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The name is derived from the similarity between this rings-and-bars winding and a squirrel cage. The solid core of the rotor is built with stacks of electrical steel laminations.
Why is the squirrel cage motor so called?
Squirrel cage motors are a subclass of induction motors, which harness electromagnetism to generate motion. They are so-called “squirrel cage” motors because the shape of their rotor – the inner component connected to the output shaft – looks like a cage.
What is a 3 phase squirrel cage motor?
A 3 phase squirrel cage induction motor is a type of three phase induction motor which functions based on the principle of electromagnetism. The interaction of the magnetic fields produced by the stator and rotor windings produces a torque on the squirrel cage rotor.
What is the difference between a squirrel cage motor in a wound rotor motor?
The phase wound motor consists external resistance circuit, whereas in squirrel cage motor it is not possible to add any external resistance circuit because their rotor bars are permanently slotted.
How does a 3 phase squirrel cage induction motor work?
Squirrel induction motor working is based on the principle of electromagnetism. When the stator winding is supplied with a three-phase AC, it produces a rotating magnetic field (RMF) which has a speed called synchronous speed. This RMF causes voltage induced in the rotor bars.
What is the purpose of squirrel cage?
The main use of a squirrel-cage motor in a home HVAC system is that it powers the blower fan. If you have a forced-air heating system, such as a furnace, and/or an air conditioning system, the squirrel-cage motor is the part that turns the fans that blows the heated and cooled air through the ventilation system.
Why can squirrel cage motor run at synchronous speed?
The induction motor can’t run at synchronous speed because it is not possible to run the motor without load. Even the motor is at no load, there would be core loss,copper loss and air friction loss.In a nut shell, the motor slip can not be zero in any case.
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.
Why are squirrel cage rotors skewed?
Skewing. The conductors are often skewed slightly along the length of the rotor to reduce noise and smooth out torque fluctuations that might result at some speeds due to interactions with the pole pieces of the stator, by ensuring that at any time the same fraction of a rotor bar is under each stator slot.
Why do squirrel cage motors have low starting torque?
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 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 is the difference between squirrel cage induction motor?
In 3 phase slip ring induction motor, the rotor resistance starter is used. When low starting torque is required, the squirrel cage motor is used. When high starting torque is required, the slip ring motor is used. Better cooling is available in this type of motor due to the presence of more space in rotor slots.
What are the two types of rotors?
There are two types of induction motor rotors: Squirrel-cage rotor or simply cage rotor. Phase wound or wound rotors.
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.
Where would you use a squirrel cage motor?
Squirrel cage induction motors are commonly used in many industrial applications. They are particularly suited for applications where the motor must maintain a constant speed, be self-starting, or there is a desire for low maintenance. These motors are commonly used in: Centrifugal pumps.
Which motors has high starting torque?
Series wound DC motors are best for applications that require high startup torque, without the need for speed regulation. Like a shunt motor, as a load is applied to a DC series motor, the motor speed decreases, which reduces the back EMF and increases the net voltage.
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 defect is found in squirrel cage motor?
Squirrel cage induction motor cast rotor defect detection with magnetic field analysis.
What is the best cage for a squirrel?
Cages at least 3 feet wide and 4 feet deep are ideal for housing two to three adult flying-squirrels as they provide sufficient room for gliding and movement without limitation. That said, the bigger the cage, the better it can accommodate more squirrels.
What is the difference between rotor speed and synchronous speed?
Induction motor with squirrel cage rotor has two different speeds. The synchronous speed refers to the stator rotating magnetic field, which depends on the number of poles and frequency. The other speed is the rotor’s. The rotor speed will be always slower than the stator speed, we call it slip.
What is slip speed?
The speed at which the induction motor work is known as the slip speed. The difference between the synchronous speed and the actual speed of the rotor is known as the slip speed. In other words, the slip speed shows the relative speed of the rotor concerning the speed of the field.
Why synchronous motors are not self starting?
Above a certain size, synchronous motors are not self-starting motors. This property is due to the inertia of the rotor; it cannot instantly follow the rotation of the magnetic field of the stator. Once the rotor nears the synchronous speed, the field winding is excited, and the motor pulls into synchronization.
