A linear induction motor is an electrical motor that is designed to produce force in a straight line (linearly) to generate the power required for a device. The basic construction of linear induction motor is similar to standard rotating motor that has been unwrapped or unfurled laterally. It is also known as alternating current induction motor.
An electric motor of any type contains two main parts- the stator and rotor. In this type of motor, the stator remains unrolled. Hence, it produces linear force along its length in place of producing rotating force (torque).
Future Applications of Linear Induction Motor
- The U.S. Navy plans to start launching future naval fixed aircraft using linear induction motor. The scientists are changing the shape of stator to flat, and the vehicle is to used in place of the rotor. This vehicle will move in straight line and will achieve high acceleration quickly.
Benefits compared to steam catapults
- 30% reduction in manning
- 20% reduction in life cycle cost
- 20% improvement in operational availability
- 50% reduction in installed size
- 50% reduction in weight
- The technology of linear induction motor may be used in a spacecraft launch system by NASA. In this system, an electromagnetic catapult will be used that has the capability to move a spacecraft along a rail system. This process will be the second stage of the spacecraft launch system, and an air-breathing engine will also be used during this stage. In the third stage the rocket will propel the vehicle into space.
- A German designer has introduced a concept to use a linear induction motor with electric vehicles. Called the Speedway Transport System, with vehicles will move, with or without carrying an on-board motor. This concept will work for any electric vehicle. They are planning a vehicle which has its own EV power train including motor, inverter and batteries, and a standard EV. When they move in highway mode, the power source will be a linear induction motor placed in the road surface and the vehicles will shut down their EV power train.
- Nepoleon Automatic Feed Company has introduced a linear induction motor driver, shutter based sheet stacking system, named Rapidstack. The new system has enhanced the capability of carrying payloads to 150 kg per stacking head with acceleration up to 20 m/s2, and velocity up to 5.5 m/s2. The travel length became unlimited due to introduction of linear induction motor.
Current Applications of Linear Induction Motor
- Linear induction motors are used for baggage handling system at major airports across the world. In London’s Heathrow, this system is used to power the baggage carts smoothly along the tracks. The force of the linear induction motor is controlled by computer system to avoid collision and to reach desired speeds. The different shapes of the track do not affect this technology such as inclined or declined track, spiral track, etc. The power consumption by this system is comparatively lower than a conveyor system shipping the same quantity of baggage, however, the speed of linear induction motor system is comparatively higher.
- Linear induction motors are currently used in various areas of industries. They are used in sewage processing structure, extrusion pullers, medical scanning instruments, gate systems, and testing equipment for road surfaces.
- The linear induction motor has wide applications in the field of public transportation. The Personal Rapid Transport systems are totally based on linear induction motor technology. It is very beneficial to use this technology for people moving systems because this technology has low maintenance requirements and long-term operational reliability. It provides contactless thrust and braking system; hence, the controlling factor of these vehicles is very high. The vehicles based on this technology can work properly even in extreme weather conditions.
- The linear induction motor system is used in some roller coaster trains due to its low cost of maintenance and riders enjoying higher speeds and unique elements.
- This technology is used in magnetic brake systems. A high level of braking power can be achieved by this technology without any moving parts and external power supply.
A linear induction motor has many advantages compared to other motors. Due to their advantages they are used worldwide. However, the main problem with this motor is that it is very expensive. Rare earth magnets are used in linear induction motor system. These magnets are very costly and make the whole system costly, too. The use of linear induction motors has been increased with time due its useful features, and it has become the future of many motor systems.
Reference – NASA’s spacecraft launch system
Reference- Rapidstack of Nepoleon Automatic Feed Company
Image: Linear Induction Motor-mix.msfc.nasa.gov
Image: Linear Induction Motor Research-nasaimages.org