Linear Induction motor is type of special purpose induction motor which is use to obtain rectilinear motor. Other conventional type of induction motor provide rotational movement. This is an advanced type of induction motor which give linear movement. In this motor stator call primary and rotor known as secondary. So the rotor side of the liner induction machines included flat aluminum conductors. These type of induction motors are now getting much popular. Linear motors are work on alternating current and its an asynchronous motor.The working principle of linear motor is same as the working principle of induction motor.
Working Principle of Linear Induction Motor
When the stator of liner induction machines is supply by the three phase supply .
The flux is travel and induced in the rotor part and travel along the entire stator part. Rotor part include the aluminum conductors and electrical current is induce into these aluminum conductors of rotor.
In these type of motor rotor (secondary) is fix and stator (primary) is moving. Synchronous speed of linear motor can represent by following equation.
fs = supply frequency (Hz)
P = number of poles in motor
Ns = synchronous speed of the motor
What is Double Sided Linear Induction Motors
In double sided linear induction motor (DLIM) there are primary on both side of the rotor side. This double liner induction motors (DLIM) are use to induce more flux from the both sides of the motor.
Efficiency of the liner induction motor is lower compare with rotary type of induction motors.
Advantages and Disadvantages of Linear Induction Motors
Following are some of the advantages and disadvantages of induction motors (Linear Motion).
Advantages of This Linear Motor
- No magnetic attraction happen at the assembly because there are no permanent magnet inside this motor.
- These type of motors work well with long length travel applications.
- This is also cost effective methods for these kind of applications.
- high force can use for these kind of applications so it’s better for heavy duty applications.
Disadvantages of liner induction machines
- Construction of this liner induction machines is some what complex .
- complex controlling methods need to use to control this motor.
- This motor do not produce any force at standstill.
- Linear induction motors are physically larger compared with permanent magnet motors.
- It got low efficiency and it consume high power.
Application of linear Induction motor
Liner induction machines are now use for so many different kind of applications which involves linear motions. Following are some of the common applications of this motors in modern day.
- Automatic sliding doors
- Mechanical conveyor belt
- liquid metal pumping
- crane material handling
- Electrical traction industries
- High voltage circuit breakers
- Electrical cranes
- use as superconducting magnets
- This principle of linear motors are widely use in rocket launching.
- High speed moving magnetic trains
Unlike rotational motor these linear motor got limit motion range.Since the motion of LIM is linear it can operate only on forward and reverse direction range only.
In our previous articles we have discuss some important features of relate to motors.
We are also hope to plan to create more content on linear induction motors on our future articles.