The three most common starting methods for squirrel cage motors are PWS (part winding start), WDS (wye-delta start), and electronic soft-start. Each serves approximately the same purpose but is dependent upon the number of contactors provided.
How does a squirrel cage induction motor work?
Squirrel cage motors maximize electromagnetic induction by utilizing rotor bars to interact with the stator’s EMF. The stator usually contains windings of wire which carry an AC current; this current changes in sync with a sinusoidal curve (or “alternates”), which changes the current direction in the wire windings.
How do I know if I have a squirrel cage induction motor?
Classification of Squirrel Cage Induction Motor
- A normal starting torque.
- A normal starting current.
- Low slip.
- In this Class, pullout torque is always of 200 to 300 percent of the full-load torque and it occurs at a low slip (it is less than 20 percent).
Which starting method is best for induction motor?
Starting of an Induction Motor
- Direct on line starter. The direct on line starter method, of an induction motor is simple and economical. …
- Star delta starter. The star delta starter method of starting three phase induction motors is very common and widely used among all the methods. …
- Auto transformer starter.
Can a squirrel cage induction motor generate electricity?
Three phase squirrel cage induction motors can also be used as generators. … For the motor to work as a generator instead of a motor the rotor must be spun faster than its stator’s synchronous speed. This will cause the motor to generate power after building up its residual magnetism.
What is the meaning of squirrel cage?
Definition of ‘squirrel cage’
1. a cage consisting of a cylindrical framework that is made to rotate by a small animal running inside the framework. 2. a repetitive purposeless task, way of life, etc.
Is a 3 phase motor AC or DC?
Three-phase motors are a type of AC motor that is a specific example of a polyphase motor. These motors can be either an induction motor (also called an asynchronous motor) or a synchronous motor.
Why starter is used in induction motor?
The three phase induction motors are self-starting due to rotating magnetic field. But the motors show tendency to draw very high current at the time of starting. … Hence there should be a device which can limit such high starting current. Such a device which limits high starting current is called a starter.11 мая 2017 г.
How do you increase the starting torque of a squirrel cage induction motor?
There were many attempts to design the rotor bar shape to increase the starting torque in squirrel cage induction motor, and it is well known that deep slot of rotor bar increases the starting torque. However, this deep slot increases the leakage flux so that it hurts the running efficiencies.
How does a single phase motor start?
A single phase induction motor consists of a single phase winding on the stator and a cage winding on the rotor. When a 1 phase supply is connected to the stator winding, a pulsating magnetic field is produced. In the pulsating field, the rotor does not rotate due to inertia.
Which type of induction motor is best for pole changing method?
This method of controlling the speed by pole changing is used mainly for cage motor only because the cage rotor automatically develops a number of poles, which is equal to the poles of the stator winding. The number of stator poles can be changed by the following three methods.
What are the starting methods of 3 phase induction motor?
The starting methods of three phase induction motor generally are direct-on-line starting, reduced-voltage starting and soft starter.
- Stator circuit series resistance starting. …
- Star-delta starting. …
- Autotransformer starting.
What are the starting methods of three phase induction motor?
- Methods of Starting Three Phase Induction Motors. …
- Direct-on-Line Starter (DOL) …
- Star Delta starter. …
- Auto-Transformer Starting. …
- Rotor Resistance Starter. …
Which type of motor has high starting torque?
DC Series motor has high starting torque. We can not start the Induction motor and Synchronous motors on load, but can not start the DC series motor without load. DC motor has high starting torque.In a series motor the same current flows through the armature and the field winding.
What is a universal electric motor?
The universal motor is a type of electric motor that can operate on either AC or DC power and uses an electromagnet as its stator to create its magnetic field. … Universal motors have high starting torque, can run at high speed, and are lightweight and compact.
How does a squirrel cage rotor work?
The field windings in the stator of an induction motor set up a rotating magnetic field through the rotor. In effect the rotor is carried around with the magnetic field but at a slightly slower rate of rotation. … The difference in speed is called slip and increases with load.