LINEAR ELECTRIC MOTOR CONCEPT:
To know the concept of linear electric motor concept first of all we will have some idea about linear electric motor.
LINEAR ELECTRIC MOTOR:
A linear electric motor is the device which converts electrical energy to mechanical energy. There are mainly three types of linear electric motor:
- Synchronous linear motor
- Induction linear motor
- Reluctance linear motor
The main aim of manufacturing of linear electric motor are as follow
- For analyzing and determining the characteristic of the variants versus long track application
- For defining the optimization criteria and design process
- For determining the best linear motor solution and its spatial integration in the lift available space
CONCEPT OF LINEAR ELECTRIC MOTOR:
The concept of linear electric motor is that it generates a moving magnetic field in the stator in which a magnetic object and rotor can travel. Genrally there are two types of design of linear electric motor depending upon the stator and moving part of the motor. Having a fixed coil design the field coil in it are static and magnets moves with coil. The advantage of moving magnet linear motor is that it can supply cables for the field coils and the measuring system is not needed to be moved. The concept of linear electric motor has proved to be very versatile. The principle objective of linear electric motor is to find a best suited motor for different application.
SYNCHRONUS MOTOR DRIVE:
The synchronus electric motor is an ac motor in which the rotation of the shaft is synchronized with the frequency of current and the rotation period is equal to number of ac cycles. Such types of motor contains electromagnet on the stator which create a magnetic field which helps in rotation with the oscillation of line current. These motor produces torque at synchronizing speed. Number of magnetic poles and the line frequency determines the speed of synchronus motor.
To understand the operation of synchronus motor it is important to understand that why the field of these motor rotates at synchronizing speed. Each of the set of stator pole is matched with equivalent set of field poles ,as we know that unlike pole attracts and like pole repel each other the poles in rotating field align themselves with opposite poles of the stator. When motor is loaded lightly,angular displacement of centerline increases. There are two factors which determines the synchronus speed of the motor:
- Frequency of the applied voltage
- Number of poles in the motor
Genrally synchronus motor are started by using different reduced voltage method and the most common one is starting across the line with full ac voltage to the armature winding. After attaining synchronus speed the starting resistor is switched out of the field circuit. The main purpose of the dc excitation is to apply current to the field winding.
1-Define linear electric motor?
2-State different types of linear electric motors?
3-Write down the aims for manufacturing of linear electric motor?
4-Write down the concept of linear electric motor?
5-What are the factors which determines the synchronus speed of motor?
6-Write down the operation of synchronus motors?